diff --git a/.travis.yml b/.travis.yml
index 4f2ee4d9..ba0113bf 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1 +1,14 @@
 language: go
+
+go:
+  - 1.4.3
+  - 1.5.3
+  - tip
+
+install:
+  - go get -t ./...
+  - go get golang.org/x/tools/cmd/vet
+
+script:
+  - go vet ./...
+  - go test -v ./...
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 850f6dfb..d6bc07e7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 ### Added:
 - CLI: The `--dns` switch. To include the DNS challenge for consideration. Supported are the following solvers: cloudflare, digitalocean, dnsimple, route53, rfc2136 and manual.
+- CLI: The `--accept-tos`  switch. Indicates your acceptance of the Let's Encrypt terms of service without prompting you.
 - lib: A new type for challenge identifiers `Challenge`
 - lib: A new interface for custom challenge providers `ChallengeProvider`
 - lib: SetChallengeProvider function. Pass a challenge identifier and a Provider to replace the default behaviour of a challenge.
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 00000000..9939a5ab
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,32 @@
+# How to contribute to lego
+
+Contributions in the form of patches and proposals are essential to keep lego great and to make it even better.
+To ensure a great and easy experience for everyone, please review the few guidelines in this document.
+
+## Bug reports
+
+- Use the issue search to see if the issue has already been reported.
+- Also look for closed issues to see if your issue has already been fixed.
+- If both of the above do not apply create a new issue and include as much information as possible.
+
+Bug reports should include all information a person could need to reproduce your problem without the need to
+follow up for more information. If possible, provide detailed steps for us to reproduce it, the expected behaviour and the actual behaviour.
+
+## Feature proposals and requests
+
+Feature requests are welcome and should be discussed in an issue.
+Please keep proposals focused on one thing at a time and be as detailed as possible.
+It is up to you to make a strong point about your proposal and convince us of the merits and the added complexity of this feature.
+
+## Pull requests
+
+Patches, new features and improvements are a great way to help the project. 
+Please keep them focused on one thing and do not include unrelated commits.
+
+All pull requests which alter the behaviour of the program, add new behaviour or somehow alter code in a non-trivial way should **always** include tests.
+
+If you want to contribute a significant pull request (with a non-trivial workload for you) please **ask first**. We do not want you to spend
+a lot of time on something the project's developers might not want to merge into the project.
+
+**IMPORTANT**: By submitting a patch, you agree to allow the project
+owners to license your work under the terms of the [MIT License](LICENSE).
diff --git a/README.md b/README.md
index a85a422c..7208a1c2 100644
--- a/README.md
+++ b/README.md
@@ -91,7 +91,7 @@ GLOBAL OPTIONS:
    --webroot 								Set the webroot folder to use for HTTP based challenges to write directly in a file in .well-known/acme-challenge
    --http 								Set the port and interface to use for HTTP based challenges to listen on. Supported: interface:port or :port
    --tls 								Set the port and interface to use for TLS based challenges to listen on. Supported: interface:port or :port
-   --dns 								Enable the DNS challenge for solving using a provider.
+   --dns 								Solve a DNS challenge using the specified provider. Disables all other solvers.
 									Credentials for providers have to be passed through environment variables.
 									For a more detailed explanation of the parameters, please see the online docs.
 									Valid providers:
@@ -99,7 +99,7 @@ GLOBAL OPTIONS:
 									digitalocean: DO_AUTH_TOKEN
 									dnsimple: DNSIMPLE_EMAIL, DNSIMPLE_API_KEY
 									route53: AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_REGION
-									rfc2136: RFC2136_TSIG_KEY, RFC2136_TSIG_SECRET, RFC2136_NAMESERVER, RFC2136_ZONE
+									rfc2136: RFC2136_TSIG_KEY, RFC2136_TSIG_SECRET, RFC2136_TSIG_ALGORITHM, RFC2136_NAMESERVER
 									manual: none
    --help, -h								show help
    --version, -v							print the version
@@ -127,9 +127,11 @@ $ lego --email="foo@bar.com" --domains="example.com" renew
 Obtain a certificate using the DNS challenge and AWS Route 53:
 
 ```bash
-$ AWS_REGION=us-east-1 AWS_ACCESS_KEY_ID=my_id AWS_SECRET_ACCESS_KEY=my_key lego --email="foo@bar.com" --domains="example.com" --dns="route53" --exclude="http-01" --exclude="tls-sni-01" run
+$ AWS_REGION=us-east-1 AWS_ACCESS_KEY_ID=my_id AWS_SECRET_ACCESS_KEY=my_key lego --email="foo@bar.com" --domains="example.com" --dns="route53" run
 ```
 
+Note that `--dns=foo` implies `--exclude=http-01` and `--exclude=tls-sni-01`. lego will not attempt other challenges if you've told it to use DNS instead.
+
 lego defaults to communicating with the production Let's Encrypt ACME server. If you'd like to test something without issuing real certificates, consider using the staging endpoint instead:
 
 ```bash
diff --git a/account.go b/account.go
index 13325470..85ac09f1 100644
--- a/account.go
+++ b/account.go
@@ -1,7 +1,7 @@
 package main
 
 import (
-	"crypto/rsa"
+	"crypto"
 	"encoding/json"
 	"io/ioutil"
 	"os"
@@ -13,7 +13,7 @@ import (
 // Account represents a users local saved credentials
 type Account struct {
 	Email        string `json:"email"`
-	key          *rsa.PrivateKey
+	key          crypto.PrivateKey
 	Registration *acme.RegistrationResource `json:"registration"`
 
 	conf *Configuration
@@ -28,16 +28,18 @@ func NewAccount(email string, conf *Configuration) *Account {
 		logger().Fatalf("Could not check/create directory for account %s: %v", email, err)
 	}
 
-	var privKey *rsa.PrivateKey
+	var privKey crypto.PrivateKey
 	if _, err := os.Stat(accKeyPath); os.IsNotExist(err) {
-		logger().Printf("No key found for account %s. Generating a %v bit key.", email, conf.RsaBits())
-		privKey, err = generateRsaKey(conf.RsaBits(), accKeyPath)
+
+		logger().Printf("No key found for account %s. Generating a curve P384 EC key.", email)
+		privKey, err = generatePrivateKey(accKeyPath)
 		if err != nil {
 			logger().Fatalf("Could not generate RSA private account key for account %s: %v", email, err)
 		}
+
 		logger().Printf("Saved key to %s", accKeyPath)
 	} else {
-		privKey, err = loadRsaKey(accKeyPath)
+		privKey, err = loadPrivateKey(accKeyPath)
 		if err != nil {
 			logger().Fatalf("Could not load RSA private key from file %s: %v", accKeyPath, err)
 		}
@@ -73,7 +75,7 @@ func (a *Account) GetEmail() string {
 }
 
 // GetPrivateKey returns the private RSA account key.
-func (a *Account) GetPrivateKey() *rsa.PrivateKey {
+func (a *Account) GetPrivateKey() crypto.PrivateKey {
 	return a.key
 }
 
diff --git a/acme/challenges.go b/acme/challenges.go
index 3f679e00..85790050 100644
--- a/acme/challenges.go
+++ b/acme/challenges.go
@@ -1,5 +1,6 @@
 package acme
 
+// Challenge is a string that identifies a particular type and version of ACME challenge.
 type Challenge string
 
 const (
diff --git a/acme/client.go b/acme/client.go
index 700aeab5..5bda6bc2 100644
--- a/acme/client.go
+++ b/acme/client.go
@@ -3,7 +3,6 @@ package acme
 
 import (
 	"crypto"
-	"crypto/rsa"
 	"crypto/x509"
 	"encoding/base64"
 	"encoding/json"
@@ -38,7 +37,7 @@ func logf(format string, args ...interface{}) {
 type User interface {
 	GetEmail() string
 	GetRegistration() *RegistrationResource
-	GetPrivateKey() *rsa.PrivateKey
+	GetPrivateKey() crypto.PrivateKey
 }
 
 // Interface for all challenge solvers to implement.
@@ -53,7 +52,7 @@ type Client struct {
 	directory  directory
 	user       User
 	jws        *jws
-	keyBits    int
+	keyType    KeyType
 	issuerCert []byte
 	solvers    map[Challenge]solver
 }
@@ -61,16 +60,12 @@ type Client struct {
 // NewClient creates a new ACME client on behalf of the user. The client will depend on
 // the ACME directory located at caDirURL for the rest of its actions. It will
 // generate private keys for certificates of size keyBits.
-func NewClient(caDirURL string, user User, keyBits int) (*Client, error) {
+func NewClient(caDirURL string, user User, keyType KeyType) (*Client, error) {
 	privKey := user.GetPrivateKey()
 	if privKey == nil {
 		return nil, errors.New("private key was nil")
 	}
 
-	if err := privKey.Validate(); err != nil {
-		return nil, fmt.Errorf("invalid private key: %v", err)
-	}
-
 	var dir directory
 	if _, err := getJSON(caDirURL, &dir); err != nil {
 		return nil, fmt.Errorf("get directory at '%s': %v", caDirURL, err)
@@ -95,10 +90,10 @@ func NewClient(caDirURL string, user User, keyBits int) (*Client, error) {
 	// Add all available solvers with the right index as per ACME
 	// spec to this map. Otherwise they won`t be found.
 	solvers := make(map[Challenge]solver)
-	solvers[HTTP01] = &httpChallenge{jws: jws, validate: validate}
-	solvers[TLSSNI01] = &tlsSNIChallenge{jws: jws, validate: validate}
+	solvers[HTTP01] = &httpChallenge{jws: jws, validate: validate, provider: &HTTPProviderServer{}}
+	solvers[TLSSNI01] = &tlsSNIChallenge{jws: jws, validate: validate, provider: &TLSProviderServer{}}
 
-	return &Client{directory: dir, user: user, jws: jws, keyBits: keyBits, solvers: solvers}, nil
+	return &Client{directory: dir, user: user, jws: jws, keyType: keyType, solvers: solvers}, nil
 }
 
 // SetChallengeProvider specifies a custom provider that will make the solution available
@@ -126,7 +121,7 @@ func (c *Client) SetHTTPAddress(iface string) error {
 	}
 
 	if chlng, ok := c.solvers[HTTP01]; ok {
-		chlng.(*httpChallenge).provider = &httpChallengeServer{iface: host, port: port}
+		chlng.(*httpChallenge).provider = NewHTTPProviderServer(host, port)
 	}
 
 	return nil
@@ -142,7 +137,7 @@ func (c *Client) SetTLSAddress(iface string) error {
 	}
 
 	if chlng, ok := c.solvers[TLSSNI01]; ok {
-		chlng.(*tlsSNIChallenge).provider = &tlsSNIChallengeServer{iface: host, port: port}
+		chlng.(*tlsSNIChallenge).provider = NewTLSProviderServer(host, port)
 	}
 	return nil
 }
@@ -197,8 +192,10 @@ func (c *Client) Register() (*RegistrationResource, error) {
 // AgreeToTOS updates the Client registration and sends the agreement to
 // the server.
 func (c *Client) AgreeToTOS() error {
-	c.user.GetRegistration().Body.Agreement = c.user.GetRegistration().TosURL
-	c.user.GetRegistration().Body.Resource = "reg"
+	reg := c.user.GetRegistration()
+
+	reg.Body.Agreement = c.user.GetRegistration().TosURL
+	reg.Body.Resource = "reg"
 	_, err := postJSON(c.jws, c.user.GetRegistration().URI, c.user.GetRegistration().Body, nil)
 	return err
 }
@@ -316,13 +313,12 @@ func (c *Client) RenewCertificate(cert CertificateResource, bundle bool) (Certif
 			links := parseLinks(resp.Header["Link"])
 			issuerCert, err := c.getIssuerCertificate(links["up"])
 			if err != nil {
-				// If we fail to aquire the issuer cert, return the issued certificate - do not fail.
+				// If we fail to acquire the issuer cert, return the issued certificate - do not fail.
 				logf("[ERROR][%s] acme: Could not bundle issuer certificate: %v", cert.Domain, err)
 			} else {
 				// Success - append the issuer cert to the issued cert.
 				issuerCert = pemEncode(derCertificateBytes(issuerCert))
 				issuedCert = append(issuedCert, issuerCert...)
-				cert.Certificate = issuedCert
 			}
 		}
 
@@ -457,7 +453,7 @@ func (c *Client) requestCertificate(authz []authorizationResource, bundle bool,
 	commonName := authz[0]
 	var err error
 	if privKey == nil {
-		privKey, err = generatePrivateKey(rsakey, c.keyBits)
+		privKey, err = generatePrivateKey(c.keyType)
 		if err != nil {
 			return CertificateResource{}, err
 		}
@@ -471,7 +467,7 @@ func (c *Client) requestCertificate(authz []authorizationResource, bundle bool,
 	}
 
 	// TODO: should the CSR be customizable?
-	csr, err := generateCsr(privKey.(*rsa.PrivateKey), commonName.Domain, san)
+	csr, err := generateCsr(privKey, commonName.Domain, san)
 	if err != nil {
 		return CertificateResource{}, err
 	}
@@ -508,6 +504,7 @@ func (c *Client) requestCertificate(authz []authorizationResource, bundle bool,
 			if len(cert) > 0 {
 
 				cerRes.CertStableURL = resp.Header.Get("Content-Location")
+				cerRes.AccountRef = c.user.GetRegistration().URI
 
 				issuedCert := pemEncode(derCertificateBytes(cert))
 				// If bundle is true, we want to return a certificate bundle.
@@ -518,7 +515,7 @@ func (c *Client) requestCertificate(authz []authorizationResource, bundle bool,
 					links := parseLinks(resp.Header["Link"])
 					issuerCert, err := c.getIssuerCertificate(links["up"])
 					if err != nil {
-						// If we fail to aquire the issuer cert, return the issued certificate - do not fail.
+						// If we fail to acquire the issuer cert, return the issued certificate - do not fail.
 						logf("[WARNING][%s] acme: Could not bundle issuer certificate: %v", commonName.Domain, err)
 					} else {
 						// Success - append the issuer cert to the issued cert.
diff --git a/acme/client_test.go b/acme/client_test.go
index c94d8f3e..e309554f 100644
--- a/acme/client_test.go
+++ b/acme/client_test.go
@@ -1,6 +1,7 @@
 package acme
 
 import (
+	"crypto"
 	"crypto/rand"
 	"crypto/rsa"
 	"encoding/json"
@@ -13,6 +14,7 @@ import (
 
 func TestNewClient(t *testing.T) {
 	keyBits := 32 // small value keeps test fast
+	keyType := RSA2048
 	key, err := rsa.GenerateKey(rand.Reader, keyBits)
 	if err != nil {
 		t.Fatal("Could not generate test key:", err)
@@ -28,7 +30,7 @@ func TestNewClient(t *testing.T) {
 		w.Write(data)
 	}))
 
-	client, err := NewClient(ts.URL, user, keyBits)
+	client, err := NewClient(ts.URL, user, keyType)
 	if err != nil {
 		t.Fatalf("Could not create client: %v", err)
 	}
@@ -40,8 +42,8 @@ func TestNewClient(t *testing.T) {
 		t.Errorf("Expected jws.privKey to be %p but was %p", expected, actual)
 	}
 
-	if client.keyBits != keyBits {
-		t.Errorf("Expected keyBits to be %d but was %d", keyBits, client.keyBits)
+	if client.keyType != keyType {
+		t.Errorf("Expected keyType to be %s but was %s", keyType, client.keyType)
 	}
 
 	if expected, actual := 2, len(client.solvers); actual != expected {
@@ -68,7 +70,7 @@ func TestClientOptPort(t *testing.T) {
 
 	optPort := "1234"
 	optHost := ""
-	client, err := NewClient(ts.URL, user, keyBits)
+	client, err := NewClient(ts.URL, user, RSA2048)
 	if err != nil {
 		t.Fatalf("Could not create client: %v", err)
 	}
@@ -82,10 +84,10 @@ func TestClientOptPort(t *testing.T) {
 	if httpSolver.jws != client.jws {
 		t.Error("Expected http-01 to have same jws as client")
 	}
-	if got := httpSolver.provider.(*httpChallengeServer).port; got != optPort {
+	if got := httpSolver.provider.(*HTTPProviderServer).port; got != optPort {
 		t.Errorf("Expected http-01 to have port %s but was %s", optPort, got)
 	}
-	if got := httpSolver.provider.(*httpChallengeServer).iface; got != optHost {
+	if got := httpSolver.provider.(*HTTPProviderServer).iface; got != optHost {
 		t.Errorf("Expected http-01 to have iface %s but was %s", optHost, got)
 	}
 
@@ -96,10 +98,10 @@ func TestClientOptPort(t *testing.T) {
 	if httpsSolver.jws != client.jws {
 		t.Error("Expected tls-sni-01 to have same jws as client")
 	}
-	if got := httpsSolver.provider.(*tlsSNIChallengeServer).port; got != optPort {
+	if got := httpsSolver.provider.(*TLSProviderServer).port; got != optPort {
 		t.Errorf("Expected tls-sni-01 to have port %s but was %s", optPort, got)
 	}
-	if got := httpsSolver.provider.(*tlsSNIChallengeServer).iface; got != optHost {
+	if got := httpsSolver.provider.(*TLSProviderServer).iface; got != optHost {
 		t.Errorf("Expected tls-sni-01 to have port %s but was %s", optHost, got)
 	}
 
@@ -108,10 +110,10 @@ func TestClientOptPort(t *testing.T) {
 	client.SetHTTPAddress(net.JoinHostPort(optHost, optPort))
 	client.SetTLSAddress(net.JoinHostPort(optHost, optPort))
 
-	if got := httpSolver.provider.(*httpChallengeServer).iface; got != optHost {
+	if got := httpSolver.provider.(*HTTPProviderServer).iface; got != optHost {
 		t.Errorf("Expected http-01 to have iface %s but was %s", optHost, got)
 	}
-	if got := httpsSolver.provider.(*tlsSNIChallengeServer).port; got != optPort {
+	if got := httpsSolver.provider.(*TLSProviderServer).port; got != optPort {
 		t.Errorf("Expected tls-sni-01 to have port %s but was %s", optPort, got)
 	}
 }
@@ -140,8 +142,8 @@ func TestValidate(t *testing.T) {
 	}))
 	defer ts.Close()
 
-	privKey, _ := generatePrivateKey(rsakey, 512)
-	j := &jws{privKey: privKey.(*rsa.PrivateKey), directoryURL: ts.URL}
+	privKey, _ := rsa.GenerateKey(rand.Reader, 512)
+	j := &jws{privKey: privKey, directoryURL: ts.URL}
 
 	tsts := []struct {
 		name     string
@@ -193,4 +195,4 @@ type mockUser struct {
 
 func (u mockUser) GetEmail() string                       { return u.email }
 func (u mockUser) GetRegistration() *RegistrationResource { return u.regres }
-func (u mockUser) GetPrivateKey() *rsa.PrivateKey         { return u.privatekey }
+func (u mockUser) GetPrivateKey() crypto.PrivateKey       { return u.privatekey }
diff --git a/acme/crypto.go b/acme/crypto.go
index 347c9bc1..fc20442f 100644
--- a/acme/crypto.go
+++ b/acme/crypto.go
@@ -10,7 +10,6 @@ import (
 	"crypto/x509"
 	"crypto/x509/pkix"
 	"encoding/base64"
-	"encoding/binary"
 	"encoding/pem"
 	"errors"
 	"fmt"
@@ -22,15 +21,19 @@ import (
 	"time"
 
 	"golang.org/x/crypto/ocsp"
-	"golang.org/x/crypto/sha3"
 )
 
-type keyType int
+// KeyType represents the key algo as well as the key size or curve to use.
+type KeyType string
 type derCertificateBytes []byte
 
+// Constants for all key types we support.
 const (
-	eckey keyType = iota
-	rsakey
+	EC256   = KeyType("P256")
+	EC384   = KeyType("P384")
+	RSA2048 = KeyType("2048")
+	RSA4096 = KeyType("4096")
+	RSA8192 = KeyType("8192")
 )
 
 const (
@@ -56,14 +59,22 @@ func GetOCSPForCert(bundle []byte) ([]byte, *ocsp.Response, error) {
 		return nil, nil, err
 	}
 
-	// We only got one certificate, means we have no issuer certificate - get it.
+	// We expect the certificate slice to be ordered downwards the chain.
+	// SRV CRT -> CA. We need to pull the leaf and issuer certs out of it,
+	// which should always be the first two certificates. If there's no
+	// OCSP server listed in the leaf cert, there's nothing to do. And if
+	// we have only one certificate so far, we need to get the issuer cert.
+	issuedCert := certificates[0]
+	if len(issuedCert.OCSPServer) == 0 {
+		return nil, nil, errors.New("no OCSP server specified in cert")
+	}
 	if len(certificates) == 1 {
 		// TODO: build fallback. If this fails, check the remaining array entries.
-		if len(certificates[0].IssuingCertificateURL) == 0 {
+		if len(issuedCert.IssuingCertificateURL) == 0 {
 			return nil, nil, errors.New("no issuing certificate URL")
 		}
 
-		resp, err := httpGet(certificates[0].IssuingCertificateURL[0])
+		resp, err := httpGet(issuedCert.IssuingCertificateURL[0])
 		if err != nil {
 			return nil, nil, err
 		}
@@ -83,17 +94,8 @@ func GetOCSPForCert(bundle []byte) ([]byte, *ocsp.Response, error) {
 		// We want it ordered right SRV CRT -> CA
 		certificates = append(certificates, issuerCert)
 	}
-
-	// We expect the certificate slice to be ordered downwards the chain.
-	// SRV CRT -> CA. We need to pull the cert and issuer cert out of it,
-	// which should always be the last two certificates.
-	issuedCert := certificates[0]
 	issuerCert := certificates[1]
 
-	if len(issuedCert.OCSPServer) == 0 {
-		return nil, nil, errors.New("no OCSP server specified in cert")
-	}
-
 	// Finally kick off the OCSP request.
 	ocspReq, err := ocsp.CreateRequest(issuedCert, issuerCert, nil)
 	if err != nil {
@@ -124,8 +126,16 @@ func GetOCSPForCert(bundle []byte) ([]byte, *ocsp.Response, error) {
 }
 
 func getKeyAuthorization(token string, key interface{}) (string, error) {
+	var publicKey crypto.PublicKey
+	switch k := key.(type) {
+	case *ecdsa.PrivateKey:
+		publicKey = k.Public()
+	case *rsa.PrivateKey:
+		publicKey = k.Public()
+	}
+
 	// Generate the Key Authorization for the challenge
-	jwk := keyAsJWK(key)
+	jwk := keyAsJWK(publicKey)
 	if jwk == nil {
 		return "", errors.New("Could not generate JWK from key.")
 	}
@@ -144,39 +154,6 @@ func getKeyAuthorization(token string, key interface{}) (string, error) {
 	return token + "." + keyThumb, nil
 }
 
-// Derive the shared secret according to acme spec 5.6
-func performECDH(priv *ecdsa.PrivateKey, pub *ecdsa.PublicKey, outLen int, label string) []byte {
-	// Derive Z from the private and public keys according to SEC 1 Ver. 2.0 - 3.3.1
-	Z, _ := priv.PublicKey.ScalarMult(pub.X, pub.Y, priv.D.Bytes())
-
-	if len(Z.Bytes())+len(label)+4 > 384 {
-		return nil
-	}
-
-	if outLen < 384*(2^32-1) {
-		return nil
-	}
-
-	// Derive the shared secret key using the ANS X9.63 KDF - SEC 1 Ver. 2.0 - 3.6.1
-	hasher := sha3.New384()
-	buffer := make([]byte, outLen)
-	bufferLen := 0
-	for i := 0; i < outLen/384; i++ {
-		hasher.Reset()
-
-		// Ki = Hash(Z || Counter || [SharedInfo])
-		hasher.Write(Z.Bytes())
-		binary.Write(hasher, binary.BigEndian, i)
-		hasher.Write([]byte(label))
-
-		hash := hasher.Sum(nil)
-		copied := copy(buffer[bufferLen:], hash)
-		bufferLen += copied
-	}
-
-	return buffer
-}
-
 // parsePEMBundle parses a certificate bundle from top to bottom and returns
 // a slice of x509 certificates. This function will error if no certificates are found.
 func parsePEMBundle(bundle []byte) ([]*x509.Certificate, error) {
@@ -218,18 +195,25 @@ func parsePEMPrivateKey(key []byte) (crypto.PrivateKey, error) {
 	}
 }
 
-func generatePrivateKey(t keyType, keyLength int) (crypto.PrivateKey, error) {
-	switch t {
-	case eckey:
+func generatePrivateKey(keyType KeyType) (crypto.PrivateKey, error) {
+
+	switch keyType {
+	case EC256:
+		return ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	case EC384:
 		return ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
-	case rsakey:
-		return rsa.GenerateKey(rand.Reader, keyLength)
+	case RSA2048:
+		return rsa.GenerateKey(rand.Reader, 2048)
+	case RSA4096:
+		return rsa.GenerateKey(rand.Reader, 4096)
+	case RSA8192:
+		return rsa.GenerateKey(rand.Reader, 8192)
 	}
 
-	return nil, fmt.Errorf("Invalid keytype: %d", t)
+	return nil, fmt.Errorf("Invalid KeyType: %s", keyType)
 }
 
-func generateCsr(privateKey *rsa.PrivateKey, domain string, san []string) ([]byte, error) {
+func generateCsr(privateKey crypto.PrivateKey, domain string, san []string) ([]byte, error) {
 	template := x509.CertificateRequest{
 		Subject: pkix.Name{
 			CommonName: domain,
@@ -246,6 +230,9 @@ func generateCsr(privateKey *rsa.PrivateKey, domain string, san []string) ([]byt
 func pemEncode(data interface{}) []byte {
 	var pemBlock *pem.Block
 	switch key := data.(type) {
+	case *ecdsa.PrivateKey:
+		keyBytes, _ := x509.MarshalECPrivateKey(key)
+		pemBlock = &pem.Block{Type: "EC PRIVATE KEY", Bytes: keyBytes}
 	case *rsa.PrivateKey:
 		pemBlock = &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(key)}
 		break
diff --git a/acme/crypto_test.go b/acme/crypto_test.go
index 81ab287e..d2fc5088 100644
--- a/acme/crypto_test.go
+++ b/acme/crypto_test.go
@@ -2,13 +2,14 @@ package acme
 
 import (
 	"bytes"
+	"crypto/rand"
 	"crypto/rsa"
 	"testing"
 	"time"
 )
 
 func TestGeneratePrivateKey(t *testing.T) {
-	key, err := generatePrivateKey(rsakey, 32)
+	key, err := generatePrivateKey(RSA2048)
 	if err != nil {
 		t.Error("Error generating private key:", err)
 	}
@@ -18,12 +19,12 @@ func TestGeneratePrivateKey(t *testing.T) {
 }
 
 func TestGenerateCSR(t *testing.T) {
-	key, err := generatePrivateKey(rsakey, 512)
+	key, err := rsa.GenerateKey(rand.Reader, 512)
 	if err != nil {
 		t.Fatal("Error generating private key:", err)
 	}
 
-	csr, err := generateCsr(key.(*rsa.PrivateKey), "fizz.buzz", nil)
+	csr, err := generateCsr(key, "fizz.buzz", nil)
 	if err != nil {
 		t.Error("Error generating CSR:", err)
 	}
@@ -52,7 +53,7 @@ func TestPEMEncode(t *testing.T) {
 }
 
 func TestPEMCertExpiration(t *testing.T) {
-	privKey, err := generatePrivateKey(rsakey, 2048)
+	privKey, err := generatePrivateKey(RSA2048)
 	if err != nil {
 		t.Fatal("Error generating private key:", err)
 	}
diff --git a/acme/dns_challenge.go b/acme/dns_challenge.go
index f34fcccc..e5be0105 100644
--- a/acme/dns_challenge.go
+++ b/acme/dns_challenge.go
@@ -6,17 +6,22 @@ import (
 	"errors"
 	"fmt"
 	"log"
+	"net"
 	"strings"
 	"time"
 
 	"github.com/miekg/dns"
+	"golang.org/x/net/publicsuffix"
 )
 
-type preCheckDNSFunc func(domain, fqdn string) bool
+type preCheckDNSFunc func(fqdn, value string) (bool, error)
 
-var preCheckDNS preCheckDNSFunc = checkDNS
+var (
+	preCheckDNS preCheckDNSFunc = checkDNSPropagation
+	fqdnToZone                  = map[string]string{}
+)
 
-var preCheckDNSFallbackCount = 5
+var recursiveNameserver = "google-public-dns-a.google.com:53"
 
 // DNS01Record returns a DNS record which will fulfill the `dns-01` challenge
 func DNS01Record(domain, keyAuth string) (fqdn string, value string, ttl int) {
@@ -44,7 +49,7 @@ func (s *dnsChallenge) Solve(chlng challenge, domain string) error {
 	}
 
 	// Generate the Key Authorization for the challenge
-	keyAuth, err := getKeyAuthorization(chlng.Token, &s.jws.privKey.PublicKey)
+	keyAuth, err := getKeyAuthorization(chlng.Token, s.jws.privKey)
 	if err != nil {
 		return err
 	}
@@ -60,54 +65,182 @@ func (s *dnsChallenge) Solve(chlng challenge, domain string) error {
 		}
 	}()
 
-	fqdn, _, _ := DNS01Record(domain, keyAuth)
+	fqdn, value, _ := DNS01Record(domain, keyAuth)
 
-	preCheckDNS(domain, fqdn)
+	logf("[INFO][%s] Checking DNS record propagation...", domain)
+
+	err = WaitFor(60*time.Second, 2*time.Second, func() (bool, error) {
+		return preCheckDNS(fqdn, value)
+	})
+	if err != nil {
+		return err
+	}
 
 	return s.validate(s.jws, domain, chlng.URI, challenge{Resource: "challenge", Type: chlng.Type, Token: chlng.Token, KeyAuthorization: keyAuth})
 }
 
-func checkDNS(domain, fqdn string) bool {
-	// check if the expected DNS entry was created. If not wait for some time and try again.
-	m := new(dns.Msg)
-	m.SetQuestion(domain+".", dns.TypeSOA)
-	c := new(dns.Client)
-	in, _, err := c.Exchange(m, "google-public-dns-a.google.com:53")
+// checkDNSPropagation checks if the expected TXT record has been propagated to all authoritative nameservers.
+func checkDNSPropagation(fqdn, value string) (bool, error) {
+	// Initial attempt to resolve at the recursive NS
+	r, err := dnsQuery(fqdn, dns.TypeTXT, recursiveNameserver, true)
 	if err != nil {
-		return false
+		return false, err
+	}
+	if r.Rcode == dns.RcodeSuccess {
+		// If we see a CNAME here then use the alias
+		for _, rr := range r.Answer {
+			if cn, ok := rr.(*dns.CNAME); ok {
+				if cn.Hdr.Name == fqdn {
+					fqdn = cn.Target
+					break
+				}
+			}
+		}
 	}
 
-	var authorativeNS string
-	for _, answ := range in.Answer {
-		soa := answ.(*dns.SOA)
-		authorativeNS = soa.Ns
+	authoritativeNss, err := lookupNameservers(fqdn)
+	if err != nil {
+		return false, err
 	}
 
-	fallbackCnt := 0
-	for fallbackCnt < preCheckDNSFallbackCount {
-		m.SetQuestion(fqdn, dns.TypeTXT)
-		in, _, err = c.Exchange(m, authorativeNS+":53")
-		if err != nil {
-			return false
-		}
-
-		if len(in.Answer) > 0 {
-			return true
-		}
-
-		fallbackCnt++
-		if fallbackCnt >= preCheckDNSFallbackCount {
-			return false
-		}
-
-		time.Sleep(time.Second * time.Duration(fallbackCnt))
-	}
-
-	return false
+	return checkAuthoritativeNss(fqdn, value, authoritativeNss)
 }
 
-// toFqdn converts the name into a fqdn appending a trailing dot.
-func toFqdn(name string) string {
+// checkAuthoritativeNss queries each of the given nameservers for the expected TXT record.
+func checkAuthoritativeNss(fqdn, value string, nameservers []string) (bool, error) {
+	for _, ns := range nameservers {
+		r, err := dnsQuery(fqdn, dns.TypeTXT, net.JoinHostPort(ns, "53"), false)
+		if err != nil {
+			return false, err
+		}
+
+		if r.Rcode != dns.RcodeSuccess {
+			return false, fmt.Errorf("NS %s returned %s for %s", ns, dns.RcodeToString[r.Rcode], fqdn)
+		}
+
+		var found bool
+		for _, rr := range r.Answer {
+			if txt, ok := rr.(*dns.TXT); ok {
+				if strings.Join(txt.Txt, "") == value {
+					found = true
+					break
+				}
+			}
+		}
+
+		if !found {
+			return false, fmt.Errorf("NS %s did not return the expected TXT record", ns)
+		}
+	}
+
+	return true, nil
+}
+
+// dnsQuery sends a DNS query to the given nameserver.
+// The nameserver should include a port, to facilitate testing where we talk to a mock dns server.
+func dnsQuery(fqdn string, rtype uint16, nameserver string, recursive bool) (in *dns.Msg, err error) {
+	m := new(dns.Msg)
+	m.SetQuestion(fqdn, rtype)
+	m.SetEdns0(4096, false)
+
+	if !recursive {
+		m.RecursionDesired = false
+	}
+
+	in, err = dns.Exchange(m, nameserver)
+	if err == dns.ErrTruncated {
+		tcp := &dns.Client{Net: "tcp"}
+		in, _, err = tcp.Exchange(m, nameserver)
+	}
+
+	return
+}
+
+// lookupNameservers returns the authoritative nameservers for the given fqdn.
+func lookupNameservers(fqdn string) ([]string, error) {
+	var authoritativeNss []string
+
+	zone, err := FindZoneByFqdn(fqdn, recursiveNameserver)
+	if err != nil {
+		return nil, err
+	}
+
+	r, err := dnsQuery(zone, dns.TypeNS, recursiveNameserver, true)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, rr := range r.Answer {
+		if ns, ok := rr.(*dns.NS); ok {
+			authoritativeNss = append(authoritativeNss, strings.ToLower(ns.Ns))
+		}
+	}
+
+	if len(authoritativeNss) > 0 {
+		return authoritativeNss, nil
+	}
+	return nil, fmt.Errorf("Could not determine authoritative nameservers")
+}
+
+// FindZoneByFqdn determines the zone of the given fqdn
+func FindZoneByFqdn(fqdn, nameserver string) (string, error) {
+	// Do we have it cached?
+	if zone, ok := fqdnToZone[fqdn]; ok {
+		return zone, nil
+	}
+
+	// Query the authorative nameserver for a hopefully non-existing SOA record,
+	// in the authority section of the reply it will have the SOA of the
+	// containing zone. rfc2308 has this to say on the subject:
+	//   Name servers authoritative for a zone MUST include the SOA record of
+	//   the zone in the authority section of the response when reporting an
+	//   NXDOMAIN or indicating that no data (NODATA) of the requested type exists
+	in, err := dnsQuery(fqdn, dns.TypeSOA, nameserver, true)
+	if err != nil {
+		return "", err
+	}
+	if in.Rcode != dns.RcodeNameError {
+		if in.Rcode != dns.RcodeSuccess {
+			return "", fmt.Errorf("NS %s returned %s for %s", nameserver, dns.RcodeToString[in.Rcode], fqdn)
+		}
+		// We have a success, so one of the answers has to be a SOA RR
+		for _, ans := range in.Answer {
+			if soa, ok := ans.(*dns.SOA); ok {
+				zone := soa.Hdr.Name
+				// If we ended up on one of the TLDs, it means the domain did not exist.
+				publicsuffix, _ := publicsuffix.PublicSuffix(UnFqdn(zone))
+				if publicsuffix == UnFqdn(zone) {
+					return "", fmt.Errorf("Could not determine zone authoritatively")
+				}
+				fqdnToZone[fqdn] = zone
+				return zone, nil
+			}
+		}
+		// Or it is NODATA, fall through to NXDOMAIN
+	}
+	// Search the authority section for our precious SOA RR
+	for _, ns := range in.Ns {
+		if soa, ok := ns.(*dns.SOA); ok {
+			zone := soa.Hdr.Name
+			// If we ended up on one of the TLDs, it means the domain did not exist.
+			publicsuffix, _ := publicsuffix.PublicSuffix(UnFqdn(zone))
+			if publicsuffix == UnFqdn(zone) {
+				return "", fmt.Errorf("Could not determine zone authoritatively")
+			}
+			fqdnToZone[fqdn] = zone
+			return zone, nil
+		}
+	}
+	return "", fmt.Errorf("NS %s did not return the expected SOA record in the authority section", nameserver)
+}
+
+// ClearFqdnCache clears the cache of fqdn to zone mappings. Primarily used in testing.
+func ClearFqdnCache() {
+	fqdnToZone = map[string]string{}
+}
+
+// ToFqdn converts the name into a fqdn appending a trailing dot.
+func ToFqdn(name string) string {
 	n := len(name)
 	if n == 0 || name[n-1] == '.' {
 		return name
@@ -115,31 +248,11 @@ func toFqdn(name string) string {
 	return name + "."
 }
 
-// unFqdn converts the fqdn into a name removing the trailing dot.
-func unFqdn(name string) string {
+// UnFqdn converts the fqdn into a name removing the trailing dot.
+func UnFqdn(name string) string {
 	n := len(name)
 	if n != 0 && name[n-1] == '.' {
 		return name[:n-1]
 	}
 	return name
 }
-
-// waitFor polls the given function 'f', once per second, up to 'timeout' seconds.
-func waitFor(timeout int, f func() (bool, error)) error {
-	start := time.Now().Second()
-	for {
-		time.Sleep(1 * time.Second)
-
-		if delta := time.Now().Second() - start; delta >= timeout {
-			return fmt.Errorf("Time limit exceeded (%d seconds)", delta)
-		}
-
-		stop, err := f()
-		if err != nil {
-			return err
-		}
-		if stop {
-			return nil
-		}
-	}
-}
diff --git a/acme/dns_challenge_cloudflare.go b/acme/dns_challenge_cloudflare.go
deleted file mode 100644
index 4781ec5b..00000000
--- a/acme/dns_challenge_cloudflare.go
+++ /dev/null
@@ -1,145 +0,0 @@
-package acme
-
-import (
-	"fmt"
-	"os"
-	"strings"
-
-	"github.com/crackcomm/cloudflare"
-	"golang.org/x/net/context"
-)
-
-// DNSProviderCloudFlare is an implementation of the DNSProvider interface
-type DNSProviderCloudFlare struct {
-	client *cloudflare.Client
-	ctx    context.Context
-}
-
-// NewDNSProviderCloudFlare returns a DNSProviderCloudFlare instance with a configured cloudflare client.
-// Authentication is either done using the passed credentials or - when empty - using the environment
-// variables CLOUDFLARE_EMAIL and CLOUDFLARE_API_KEY.
-func NewDNSProviderCloudFlare(cloudflareEmail, cloudflareKey string) (*DNSProviderCloudFlare, error) {
-	if cloudflareEmail == "" || cloudflareKey == "" {
-		cloudflareEmail, cloudflareKey = cloudflareEnvAuth()
-		if cloudflareEmail == "" || cloudflareKey == "" {
-			return nil, fmt.Errorf("CloudFlare credentials missing")
-		}
-	}
-
-	c := &DNSProviderCloudFlare{
-		client: cloudflare.New(&cloudflare.Options{cloudflareEmail, cloudflareKey}),
-		ctx:    context.Background(),
-	}
-
-	return c, nil
-}
-
-// Present creates a TXT record to fulfil the dns-01 challenge
-func (c *DNSProviderCloudFlare) Present(domain, token, keyAuth string) error {
-	fqdn, value, ttl := DNS01Record(domain, keyAuth)
-	zoneID, err := c.getHostedZoneID(fqdn)
-	if err != nil {
-		return err
-	}
-
-	record := newTxtRecord(zoneID, fqdn, value, ttl)
-	err = c.client.Records.Create(c.ctx, record)
-	if err != nil {
-		return fmt.Errorf("CloudFlare API call failed: %v", err)
-	}
-
-	return nil
-}
-
-// CleanUp removes the TXT record matching the specified parameters
-func (c *DNSProviderCloudFlare) CleanUp(domain, token, keyAuth string) error {
-	fqdn, _, _ := DNS01Record(domain, keyAuth)
-	records, err := c.findTxtRecords(fqdn)
-	if err != nil {
-		return err
-	}
-
-	for _, rec := range records {
-		err := c.client.Records.Delete(c.ctx, rec.ZoneID, rec.ID)
-		if err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-func (c *DNSProviderCloudFlare) findTxtRecords(fqdn string) ([]*cloudflare.Record, error) {
-	zoneID, err := c.getHostedZoneID(fqdn)
-	if err != nil {
-		return nil, err
-	}
-
-	var records []*cloudflare.Record
-	result, err := c.client.Records.List(c.ctx, zoneID)
-	if err != nil {
-		return records, fmt.Errorf("CloudFlare API call has failed: %v", err)
-	}
-
-	name := unFqdn(fqdn)
-	for _, rec := range result {
-		if rec.Name == name && rec.Type == "TXT" {
-			records = append(records, rec)
-		}
-	}
-
-	return records, nil
-}
-
-func (c *DNSProviderCloudFlare) getHostedZoneID(fqdn string) (string, error) {
-	zones, err := c.client.Zones.List(c.ctx)
-	if err != nil {
-		return "", fmt.Errorf("CloudFlare API call failed: %v", err)
-	}
-
-	var hostedZone cloudflare.Zone
-	for _, zone := range zones {
-		name := toFqdn(zone.Name)
-		if strings.HasSuffix(fqdn, name) {
-			if len(zone.Name) > len(hostedZone.Name) {
-				hostedZone = *zone
-			}
-		}
-	}
-	if hostedZone.ID == "" {
-		return "", fmt.Errorf("No matching CloudFlare zone found for domain %s", fqdn)
-	}
-
-	return hostedZone.ID, nil
-}
-
-func newTxtRecord(zoneID, fqdn, value string, ttl int) *cloudflare.Record {
-	name := unFqdn(fqdn)
-	return &cloudflare.Record{
-		Type:    "TXT",
-		Name:    name,
-		Content: value,
-		TTL:     sanitizeTTL(ttl),
-		ZoneID:  zoneID,
-	}
-}
-
-// TTL must be between 120 and 86400 seconds
-func sanitizeTTL(ttl int) int {
-	switch {
-	case ttl < 120:
-		return 120
-	case ttl > 86400:
-		return 86400
-	default:
-		return ttl
-	}
-}
-
-func cloudflareEnvAuth() (email, apiKey string) {
-	email = os.Getenv("CLOUDFLARE_EMAIL")
-	apiKey = os.Getenv("CLOUDFLARE_API_KEY")
-	if len(email) == 0 || len(apiKey) == 0 {
-		return "", ""
-	}
-	return
-}
diff --git a/acme/dns_challenge_rfc2136.go b/acme/dns_challenge_rfc2136.go
deleted file mode 100644
index e6f93fa4..00000000
--- a/acme/dns_challenge_rfc2136.go
+++ /dev/null
@@ -1,90 +0,0 @@
-package acme
-
-import (
-	"fmt"
-	"github.com/miekg/dns"
-	"time"
-)
-
-// DNSProviderRFC2136 is an implementation of the ChallengeProvider interface that
-// uses dynamic DNS updates (RFC 2136) to create TXT records on a nameserver.
-type DNSProviderRFC2136 struct {
-	nameserver string
-	zone       string
-	tsigKey    string
-	tsigSecret string
-	records    map[string]string
-}
-
-// NewDNSProviderRFC2136 returns a new DNSProviderRFC2136 instance.
-// To disable TSIG authentication 'tsigKey' and 'tsigSecret' must be set to the empty string.
-// 'nameserver' must be a network address in the the form "host:port". 'zone' must be the fully
-// qualified name of the zone.
-func NewDNSProviderRFC2136(nameserver, zone, tsigKey, tsigSecret string) (*DNSProviderRFC2136, error) {
-	d := &DNSProviderRFC2136{
-		nameserver: nameserver,
-		zone:       zone,
-		records:    make(map[string]string),
-	}
-	if len(tsigKey) > 0 && len(tsigSecret) > 0 {
-		d.tsigKey = tsigKey
-		d.tsigSecret = tsigSecret
-	}
-
-	return d, nil
-}
-
-// Present creates a TXT record using the specified parameters
-func (r *DNSProviderRFC2136) Present(domain, token, keyAuth string) error {
-	fqdn, value, ttl := DNS01Record(domain, keyAuth)
-	r.records[fqdn] = value
-	return r.changeRecord("INSERT", fqdn, value, ttl)
-}
-
-// CleanUp removes the TXT record matching the specified parameters
-func (r *DNSProviderRFC2136) CleanUp(domain, token, keyAuth string) error {
-	fqdn, _, ttl := DNS01Record(domain, keyAuth)
-	value := r.records[fqdn]
-	return r.changeRecord("REMOVE", fqdn, value, ttl)
-}
-
-func (r *DNSProviderRFC2136) changeRecord(action, fqdn, value string, ttl int) error {
-	// Create RR
-	rr := new(dns.TXT)
-	rr.Hdr = dns.RR_Header{Name: fqdn, Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: uint32(ttl)}
-	rr.Txt = []string{value}
-	rrs := make([]dns.RR, 1)
-	rrs[0] = rr
-
-	// Create dynamic update packet
-	m := new(dns.Msg)
-	m.SetUpdate(dns.Fqdn(r.zone))
-	switch action {
-	case "INSERT":
-		m.Insert(rrs)
-	case "REMOVE":
-		m.Remove(rrs)
-	default:
-		return fmt.Errorf("Unexpected action: %s", action)
-	}
-
-	// Setup client
-	c := new(dns.Client)
-	c.SingleInflight = true
-	// TSIG authentication / msg signing
-	if len(r.tsigKey) > 0 && len(r.tsigSecret) > 0 {
-		m.SetTsig(dns.Fqdn(r.tsigKey), dns.HmacMD5, 300, time.Now().Unix())
-		c.TsigSecret = map[string]string{dns.Fqdn(r.tsigKey): r.tsigSecret}
-	}
-
-	// Send the query
-	reply, _, err := c.Exchange(m, r.nameserver)
-	if err != nil {
-		return fmt.Errorf("DNS update failed: %v", err)
-	}
-	if reply != nil && reply.Rcode != dns.RcodeSuccess {
-		return fmt.Errorf("DNS update failed. Server replied: %s", dns.RcodeToString[reply.Rcode])
-	}
-
-	return nil
-}
diff --git a/acme/dns_challenge_test.go b/acme/dns_challenge_test.go
index 0af40f71..bfc66561 100644
--- a/acme/dns_challenge_test.go
+++ b/acme/dns_challenge_test.go
@@ -2,19 +2,86 @@ package acme
 
 import (
 	"bufio"
+	"crypto/rand"
 	"crypto/rsa"
 	"net/http"
 	"net/http/httptest"
 	"os"
+	"reflect"
+	"sort"
+	"strings"
 	"testing"
 	"time"
 )
 
+var lookupNameserversTestsOK = []struct {
+	fqdn string
+	nss  []string
+}{
+	{"books.google.com.ng.",
+		[]string{"ns1.google.com.", "ns2.google.com.", "ns3.google.com.", "ns4.google.com."},
+	},
+	{"www.google.com.",
+		[]string{"ns1.google.com.", "ns2.google.com.", "ns3.google.com.", "ns4.google.com."},
+	},
+	{"physics.georgetown.edu.",
+		[]string{"ns1.georgetown.edu.", "ns2.georgetown.edu.", "ns3.georgetown.edu."},
+	},
+}
+
+var lookupNameserversTestsErr = []struct {
+	fqdn  string
+	error string
+}{
+	// invalid tld
+	{"_null.n0n0.",
+		"Could not determine zone authoritatively",
+	},
+	// invalid domain
+	{"_null.com.",
+		"Could not determine zone authoritatively",
+	},
+	// invalid domain
+	{"in-valid.co.uk.",
+		"Could not determine zone authoritatively",
+	},
+}
+
+var checkAuthoritativeNssTests = []struct {
+	fqdn, value string
+	ns          []string
+	ok          bool
+}{
+	// TXT RR w/ expected value
+	{"8.8.8.8.asn.routeviews.org.", "151698.8.8.024", []string{"asnums.routeviews.org."},
+		true,
+	},
+	// No TXT RR
+	{"ns1.google.com.", "", []string{"ns2.google.com."},
+		false,
+	},
+}
+
+var checkAuthoritativeNssTestsErr = []struct {
+	fqdn, value string
+	ns          []string
+	error       string
+}{
+	// TXT RR /w unexpected value
+	{"8.8.8.8.asn.routeviews.org.", "fe01=", []string{"asnums.routeviews.org."},
+		"did not return the expected TXT record",
+	},
+	// No TXT RR
+	{"ns1.google.com.", "fe01=", []string{"ns2.google.com."},
+		"did not return the expected TXT record",
+	},
+}
+
 func TestDNSValidServerResponse(t *testing.T) {
-	preCheckDNS = func(domain, fqdn string) bool {
-		return true
+	preCheckDNS = func(fqdn, value string) (bool, error) {
+		return true, nil
 	}
-	privKey, _ := generatePrivateKey(rsakey, 512)
+	privKey, _ := rsa.GenerateKey(rand.Reader, 512)
 
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Add("Replay-Nonce", "12345")
@@ -22,7 +89,7 @@ func TestDNSValidServerResponse(t *testing.T) {
 	}))
 
 	manualProvider, _ := NewDNSProviderManual()
-	jws := &jws{privKey: privKey.(*rsa.PrivateKey), directoryURL: ts.URL}
+	jws := &jws{privKey: privKey, directoryURL: ts.URL}
 	solver := &dnsChallenge{jws: jws, validate: validate, provider: manualProvider}
 	clientChallenge := challenge{Type: "dns01", Status: "pending", URI: ts.URL, Token: "http8"}
 
@@ -39,7 +106,60 @@ func TestDNSValidServerResponse(t *testing.T) {
 }
 
 func TestPreCheckDNS(t *testing.T) {
-	if !preCheckDNS("api.letsencrypt.org", "acme-staging.api.letsencrypt.org") {
+	ok, err := preCheckDNS("acme-staging.api.letsencrypt.org", "fe01=")
+	if err != nil || !ok {
 		t.Errorf("preCheckDNS failed for acme-staging.api.letsencrypt.org")
 	}
 }
+
+func TestLookupNameserversOK(t *testing.T) {
+	for _, tt := range lookupNameserversTestsOK {
+		nss, err := lookupNameservers(tt.fqdn)
+		if err != nil {
+			t.Fatalf("#%s: got %q; want nil", tt.fqdn, err)
+		}
+
+		sort.Strings(nss)
+		sort.Strings(tt.nss)
+
+		if !reflect.DeepEqual(nss, tt.nss) {
+			t.Errorf("#%s: got %v; want %v", tt.fqdn, nss, tt.nss)
+		}
+	}
+}
+
+func TestLookupNameserversErr(t *testing.T) {
+	for _, tt := range lookupNameserversTestsErr {
+		_, err := lookupNameservers(tt.fqdn)
+		if err == nil {
+			t.Fatalf("#%s: expected %q (error); got <nil>", tt.fqdn, tt.error)
+		}
+
+		if !strings.Contains(err.Error(), tt.error) {
+			t.Errorf("#%s: expected %q (error); got %q", tt.fqdn, tt.error, err)
+			continue
+		}
+	}
+}
+
+func TestCheckAuthoritativeNss(t *testing.T) {
+	for _, tt := range checkAuthoritativeNssTests {
+		ok, _ := checkAuthoritativeNss(tt.fqdn, tt.value, tt.ns)
+		if ok != tt.ok {
+			t.Errorf("%s: got %t; want %t", tt.fqdn, ok, tt.ok)
+		}
+	}
+}
+
+func TestCheckAuthoritativeNssErr(t *testing.T) {
+	for _, tt := range checkAuthoritativeNssTestsErr {
+		_, err := checkAuthoritativeNss(tt.fqdn, tt.value, tt.ns)
+		if err == nil {
+			t.Fatalf("#%s: expected %q (error); got <nil>", tt.fqdn, tt.error)
+		}
+		if !strings.Contains(err.Error(), tt.error) {
+			t.Errorf("#%s: expected %q (error); got %q", tt.fqdn, tt.error, err)
+			continue
+		}
+	}
+}
diff --git a/acme/http.go b/acme/http.go
index 6933899b..410aead6 100644
--- a/acme/http.go
+++ b/acme/http.go
@@ -8,11 +8,15 @@ import (
 	"net/http"
 	"runtime"
 	"strings"
+	"time"
 )
 
 // UserAgent (if non-empty) will be tacked onto the User-Agent string in requests.
 var UserAgent string
 
+// defaultClient is an HTTP client with a reasonable timeout value.
+var defaultClient = http.Client{Timeout: 10 * time.Second}
+
 const (
 	// defaultGoUserAgent is the Go HTTP package user agent string. Too
 	// bad it isn't exported. If it changes, we should update it here, too.
@@ -32,7 +36,7 @@ func httpHead(url string) (resp *http.Response, err error) {
 
 	req.Header.Set("User-Agent", userAgent())
 
-	resp, err = http.DefaultClient.Do(req)
+	resp, err = defaultClient.Do(req)
 	if err != nil {
 		return resp, err
 	}
@@ -50,7 +54,7 @@ func httpPost(url string, bodyType string, body io.Reader) (resp *http.Response,
 	req.Header.Set("Content-Type", bodyType)
 	req.Header.Set("User-Agent", userAgent())
 
-	return http.DefaultClient.Do(req)
+	return defaultClient.Do(req)
 }
 
 // httpGet performs a GET request with a proper User-Agent string.
@@ -62,7 +66,7 @@ func httpGet(url string) (resp *http.Response, err error) {
 	}
 	req.Header.Set("User-Agent", userAgent())
 
-	return http.DefaultClient.Do(req)
+	return defaultClient.Do(req)
 }
 
 // getJSON performs an HTTP GET request and parses the response body
diff --git a/acme/http_challenge.go b/acme/http_challenge.go
index a9f8e5cf..95cb1fd8 100644
--- a/acme/http_challenge.go
+++ b/acme/http_challenge.go
@@ -21,15 +21,11 @@ func (s *httpChallenge) Solve(chlng challenge, domain string) error {
 	logf("[INFO][%s] acme: Trying to solve HTTP-01", domain)
 
 	// Generate the Key Authorization for the challenge
-	keyAuth, err := getKeyAuthorization(chlng.Token, &s.jws.privKey.PublicKey)
+	keyAuth, err := getKeyAuthorization(chlng.Token, s.jws.privKey)
 	if err != nil {
 		return err
 	}
 
-	if s.provider == nil {
-		s.provider = &httpChallengeServer{}
-	}
-
 	err = s.provider.Present(domain, chlng.Token, keyAuth)
 	if err != nil {
 		return fmt.Errorf("[%s] error presenting token: %v", domain, err)
diff --git a/acme/http_challenge_server.go b/acme/http_challenge_server.go
index 33882236..42541380 100644
--- a/acme/http_challenge_server.go
+++ b/acme/http_challenge_server.go
@@ -7,16 +7,25 @@ import (
 	"strings"
 )
 
-// httpChallengeServer implements ChallengeProvider for `http-01` challenge
-type httpChallengeServer struct {
+// HTTPProviderServer implements ChallengeProvider for `http-01` challenge
+// It may be instantiated without using the NewHTTPProviderServer function if
+// you want only to use the default values.
+type HTTPProviderServer struct {
 	iface    string
 	port     string
 	done     chan bool
 	listener net.Listener
 }
 
-// Present makes the token available at `HTTP01ChallengePath(token)`
-func (s *httpChallengeServer) Present(domain, token, keyAuth string) error {
+// NewHTTPProviderServer creates a new HTTPProviderServer on the selected interface and port.
+// Setting iface and / or port to an empty string will make the server fall back to
+// the "any" interface and port 80 respectively.
+func NewHTTPProviderServer(iface, port string) *HTTPProviderServer {
+	return &HTTPProviderServer{iface: iface, port: port}
+}
+
+// Present starts a web server and makes the token available at `HTTP01ChallengePath(token)` for web requests.
+func (s *HTTPProviderServer) Present(domain, token, keyAuth string) error {
 	if s.port == "" {
 		s.port = "80"
 	}
@@ -32,7 +41,8 @@ func (s *httpChallengeServer) Present(domain, token, keyAuth string) error {
 	return nil
 }
 
-func (s *httpChallengeServer) CleanUp(domain, token, keyAuth string) error {
+// CleanUp closes the HTTP server and removes the token from `HTTP01ChallengePath(token)`
+func (s *HTTPProviderServer) CleanUp(domain, token, keyAuth string) error {
 	if s.listener == nil {
 		return nil
 	}
@@ -41,7 +51,7 @@ func (s *httpChallengeServer) CleanUp(domain, token, keyAuth string) error {
 	return nil
 }
 
-func (s *httpChallengeServer) serve(domain, token, keyAuth string) {
+func (s *HTTPProviderServer) serve(domain, token, keyAuth string) {
 	path := HTTP01ChallengePath(token)
 
 	// The handler validates the HOST header and request type.
diff --git a/acme/http_challenge_test.go b/acme/http_challenge_test.go
index 56f07345..b1e77543 100644
--- a/acme/http_challenge_test.go
+++ b/acme/http_challenge_test.go
@@ -1,6 +1,7 @@
 package acme
 
 import (
+	"crypto/rand"
 	"crypto/rsa"
 	"io/ioutil"
 	"os"
@@ -9,8 +10,8 @@ import (
 )
 
 func TestHTTPChallenge(t *testing.T) {
-	privKey, _ := generatePrivateKey(rsakey, 512)
-	j := &jws{privKey: privKey.(*rsa.PrivateKey)}
+	privKey, _ := rsa.GenerateKey(rand.Reader, 512)
+	j := &jws{privKey: privKey}
 	clientChallenge := challenge{Type: HTTP01, Token: "http1"}
 	mockValidate := func(_ *jws, _, _ string, chlng challenge) error {
 		uri := "http://localhost:23457/.well-known/acme-challenge/" + chlng.Token
@@ -36,7 +37,7 @@ func TestHTTPChallenge(t *testing.T) {
 
 		return nil
 	}
-	solver := &httpChallenge{jws: j, validate: mockValidate, provider: &httpChallengeServer{port: "23457"}}
+	solver := &httpChallenge{jws: j, validate: mockValidate, provider: &HTTPProviderServer{port: "23457"}}
 
 	if err := solver.Solve(clientChallenge, "localhost:23457"); err != nil {
 		t.Errorf("Solve error: got %v, want nil", err)
@@ -44,10 +45,10 @@ func TestHTTPChallenge(t *testing.T) {
 }
 
 func TestHTTPChallengeInvalidPort(t *testing.T) {
-	privKey, _ := generatePrivateKey(rsakey, 128)
-	j := &jws{privKey: privKey.(*rsa.PrivateKey)}
+	privKey, _ := rsa.GenerateKey(rand.Reader, 128)
+	j := &jws{privKey: privKey}
 	clientChallenge := challenge{Type: HTTP01, Token: "http2"}
-	solver := &httpChallenge{jws: j, validate: stubValidate, provider: &httpChallengeServer{port: "123456"}}
+	solver := &httpChallenge{jws: j, validate: stubValidate, provider: &HTTPProviderServer{port: "123456"}}
 
 	if err := solver.Solve(clientChallenge, "localhost:123456"); err == nil {
 		t.Errorf("Solve error: got %v, want error", err)
diff --git a/acme/jws.go b/acme/jws.go
index b676fe39..78d82724 100644
--- a/acme/jws.go
+++ b/acme/jws.go
@@ -2,7 +2,9 @@ package acme
 
 import (
 	"bytes"
+	"crypto"
 	"crypto/ecdsa"
+	"crypto/elliptic"
 	"crypto/rsa"
 	"fmt"
 	"net/http"
@@ -12,7 +14,7 @@ import (
 
 type jws struct {
 	directoryURL string
-	privKey      *rsa.PrivateKey
+	privKey      crypto.PrivateKey
 	nonces       []string
 }
 
@@ -46,8 +48,20 @@ func (j *jws) post(url string, content []byte) (*http.Response, error) {
 }
 
 func (j *jws) signContent(content []byte) (*jose.JsonWebSignature, error) {
-	// TODO: support other algorithms - RS512
-	signer, err := jose.NewSigner(jose.RS256, j.privKey)
+
+	var alg jose.SignatureAlgorithm
+	switch k := j.privKey.(type) {
+	case *rsa.PrivateKey:
+		alg = jose.RS256
+	case *ecdsa.PrivateKey:
+		if k.Curve == elliptic.P256() {
+			alg = jose.ES256
+		} else if k.Curve == elliptic.P384() {
+			alg = jose.ES384
+		}
+	}
+
+	signer, err := jose.NewSigner(alg, j.privKey)
 	if err != nil {
 		return nil, err
 	}
diff --git a/acme/messages.go b/acme/messages.go
index 55e54321..fe3f5748 100644
--- a/acme/messages.go
+++ b/acme/messages.go
@@ -28,17 +28,13 @@ type registrationMessage struct {
 // Registration is returned by the ACME server after the registration
 // The client implementation should save this registration somewhere.
 type Registration struct {
-	Resource string `json:"resource,omitempty"`
-	ID       int    `json:"id"`
-	Key      struct {
-		Kty string `json:"kty"`
-		N   string `json:"n"`
-		E   string `json:"e"`
-	} `json:"key"`
-	Contact        []string `json:"contact"`
-	Agreement      string   `json:"agreement,omitempty"`
-	Authorizations string   `json:"authorizations,omitempty"`
-	Certificates   string   `json:"certificates,omitempty"`
+	Resource       string          `json:"resource,omitempty"`
+	ID             int             `json:"id"`
+	Key            jose.JsonWebKey `json:"key"`
+	Contact        []string        `json:"contact"`
+	Agreement      string          `json:"agreement,omitempty"`
+	Authorizations string          `json:"authorizations,omitempty"`
+	Certificates   string          `json:"certificates,omitempty"`
 	//	RecoveryKey    recoveryKeyMessage `json:"recoveryKey,omitempty"`
 }
 
@@ -113,6 +109,7 @@ type CertificateResource struct {
 	Domain        string `json:"domain"`
 	CertURL       string `json:"certUrl"`
 	CertStableURL string `json:"certStableUrl"`
+	AccountRef    string `json:"accountRef,omitempty"`
 	PrivateKey    []byte `json:"-"`
 	Certificate   []byte `json:"-"`
 }
diff --git a/acme/tls_sni_challenge.go b/acme/tls_sni_challenge.go
index 2ab3abd0..c36f6acc 100644
--- a/acme/tls_sni_challenge.go
+++ b/acme/tls_sni_challenge.go
@@ -22,15 +22,11 @@ func (t *tlsSNIChallenge) Solve(chlng challenge, domain string) error {
 	logf("[INFO][%s] acme: Trying to solve TLS-SNI-01", domain)
 
 	// Generate the Key Authorization for the challenge
-	keyAuth, err := getKeyAuthorization(chlng.Token, &t.jws.privKey.PublicKey)
+	keyAuth, err := getKeyAuthorization(chlng.Token, t.jws.privKey)
 	if err != nil {
 		return err
 	}
 
-	if t.provider == nil {
-		t.provider = &tlsSNIChallengeServer{}
-	}
-
 	err = t.provider.Present(domain, chlng.Token, keyAuth)
 	if err != nil {
 		return fmt.Errorf("[%s] error presenting token: %v", domain, err)
@@ -47,7 +43,7 @@ func (t *tlsSNIChallenge) Solve(chlng challenge, domain string) error {
 // TLSSNI01ChallengeCert returns a certificate for the `tls-sni-01` challenge
 func TLSSNI01ChallengeCert(keyAuth string) (tls.Certificate, error) {
 	// generate a new RSA key for the certificates
-	tempPrivKey, err := generatePrivateKey(rsakey, 2048)
+	tempPrivKey, err := generatePrivateKey(RSA2048)
 	if err != nil {
 		return tls.Certificate{}, err
 	}
diff --git a/acme/tls_sni_challenge_server.go b/acme/tls_sni_challenge_server.go
index 13749632..faaf16f6 100644
--- a/acme/tls_sni_challenge_server.go
+++ b/acme/tls_sni_challenge_server.go
@@ -7,16 +7,25 @@ import (
 	"net/http"
 )
 
-// tlsSNIChallengeServer implements ChallengeProvider for `TLS-SNI-01` challenge
-type tlsSNIChallengeServer struct {
+// TLSProviderServer implements ChallengeProvider for `TLS-SNI-01` challenge
+// It may be instantiated without using the NewTLSProviderServer function if
+// you want only to use the default values.
+type TLSProviderServer struct {
 	iface    string
 	port     string
 	done     chan bool
 	listener net.Listener
 }
 
+// NewTLSProviderServer creates a new TLSProviderServer on the selected interface and port.
+// Setting iface and / or port to an empty string will make the server fall back to
+// the "any" interface and port 443 respectively.
+func NewTLSProviderServer(iface, port string) *TLSProviderServer {
+	return &TLSProviderServer{iface: iface, port: port}
+}
+
 // Present makes the keyAuth available as a cert
-func (s *tlsSNIChallengeServer) Present(domain, token, keyAuth string) error {
+func (s *TLSProviderServer) Present(domain, token, keyAuth string) error {
 	if s.port == "" {
 		s.port = "443"
 	}
@@ -42,7 +51,8 @@ func (s *tlsSNIChallengeServer) Present(domain, token, keyAuth string) error {
 	return nil
 }
 
-func (s *tlsSNIChallengeServer) CleanUp(domain, token, keyAuth string) error {
+// CleanUp closes the HTTP server.
+func (s *TLSProviderServer) CleanUp(domain, token, keyAuth string) error {
 	if s.listener == nil {
 		return nil
 	}
diff --git a/acme/tls_sni_challenge_test.go b/acme/tls_sni_challenge_test.go
index 3372912f..3aec7456 100644
--- a/acme/tls_sni_challenge_test.go
+++ b/acme/tls_sni_challenge_test.go
@@ -1,6 +1,7 @@
 package acme
 
 import (
+	"crypto/rand"
 	"crypto/rsa"
 	"crypto/sha256"
 	"crypto/tls"
@@ -11,8 +12,8 @@ import (
 )
 
 func TestTLSSNIChallenge(t *testing.T) {
-	privKey, _ := generatePrivateKey(rsakey, 512)
-	j := &jws{privKey: privKey.(*rsa.PrivateKey)}
+	privKey, _ := rsa.GenerateKey(rand.Reader, 512)
+	j := &jws{privKey: privKey}
 	clientChallenge := challenge{Type: TLSSNI01, Token: "tlssni1"}
 	mockValidate := func(_ *jws, _, _ string, chlng challenge) error {
 		conn, err := tls.Dial("tcp", "localhost:23457", &tls.Config{
@@ -43,7 +44,7 @@ func TestTLSSNIChallenge(t *testing.T) {
 
 		return nil
 	}
-	solver := &tlsSNIChallenge{jws: j, validate: mockValidate, provider: &tlsSNIChallengeServer{port: "23457"}}
+	solver := &tlsSNIChallenge{jws: j, validate: mockValidate, provider: &TLSProviderServer{port: "23457"}}
 
 	if err := solver.Solve(clientChallenge, "localhost:23457"); err != nil {
 		t.Errorf("Solve error: got %v, want nil", err)
@@ -51,10 +52,10 @@ func TestTLSSNIChallenge(t *testing.T) {
 }
 
 func TestTLSSNIChallengeInvalidPort(t *testing.T) {
-	privKey, _ := generatePrivateKey(rsakey, 128)
-	j := &jws{privKey: privKey.(*rsa.PrivateKey)}
+	privKey, _ := rsa.GenerateKey(rand.Reader, 128)
+	j := &jws{privKey: privKey}
 	clientChallenge := challenge{Type: TLSSNI01, Token: "tlssni2"}
-	solver := &tlsSNIChallenge{jws: j, validate: stubValidate, provider: &tlsSNIChallengeServer{port: "123456"}}
+	solver := &tlsSNIChallenge{jws: j, validate: stubValidate, provider: &TLSProviderServer{port: "123456"}}
 
 	if err := solver.Solve(clientChallenge, "localhost:123456"); err == nil {
 		t.Errorf("Solve error: got %v, want error", err)
diff --git a/acme/utils.go b/acme/utils.go
new file mode 100644
index 00000000..2fa0db30
--- /dev/null
+++ b/acme/utils.go
@@ -0,0 +1,29 @@
+package acme
+
+import (
+	"fmt"
+	"time"
+)
+
+// WaitFor polls the given function 'f', once every 'interval', up to 'timeout'.
+func WaitFor(timeout, interval time.Duration, f func() (bool, error)) error {
+	var lastErr string
+	timeup := time.After(timeout)
+	for {
+		select {
+		case <-timeup:
+			return fmt.Errorf("Time limit exceeded. Last error: %s", lastErr)
+		default:
+		}
+
+		stop, err := f()
+		if stop {
+			return nil
+		}
+		if err != nil {
+			lastErr = err.Error()
+		}
+
+		time.Sleep(interval)
+	}
+}
diff --git a/acme/utils_test.go b/acme/utils_test.go
new file mode 100644
index 00000000..158af411
--- /dev/null
+++ b/acme/utils_test.go
@@ -0,0 +1,26 @@
+package acme
+
+import (
+	"testing"
+	"time"
+)
+
+func TestWaitForTimeout(t *testing.T) {
+	c := make(chan error)
+	go func() {
+		err := WaitFor(3*time.Second, 1*time.Second, func() (bool, error) {
+			return false, nil
+		})
+		c <- err
+	}()
+
+	timeout := time.After(4 * time.Second)
+	select {
+	case <-timeout:
+		t.Fatal("timeout exceeded")
+	case err := <-c:
+		if err == nil {
+			t.Errorf("expected timeout error; got %v", err)
+		}
+	}
+}
diff --git a/cli.go b/cli.go
index f0edccf5..83360a45 100644
--- a/cli.go
+++ b/cli.go
@@ -50,6 +50,12 @@ func main() {
 			Name:   "run",
 			Usage:  "Register an account, then create and install a certificate",
 			Action: run,
+			Flags: []cli.Flag{
+				cli.BoolFlag{
+					Name:  "no-bundle",
+					Usage: "Do not create a certificate bundle by adding the issuers certificate to the new certificate.",
+				},
+			},
 		},
 		{
 			Name:   "revoke",
@@ -70,6 +76,10 @@ func main() {
 					Name:  "reuse-key",
 					Usage: "Used to indicate you want to reuse your current private key for the new certificate.",
 				},
+				cli.BoolFlag{
+					Name:  "no-bundle",
+					Usage: "Do not create a certificate bundle by adding the issuers certificate to the new certificate.",
+				},
 			},
 		},
 	}
@@ -88,10 +98,14 @@ func main() {
 			Name:  "email, m",
 			Usage: "Email used for registration and recovery contact.",
 		},
-		cli.IntFlag{
-			Name:  "rsa-key-size, B",
-			Value: 2048,
-			Usage: "Size of the RSA key.",
+		cli.BoolFlag{
+			Name:  "accept-tos, a",
+			Usage: "By setting this flag to true you indicate that you accept the current Let's Encrypt terms of service.",
+		},
+		cli.StringFlag{
+			Name:  "key-type, k",
+			Value: "rsa2048",
+			Usage: "Key type to use for private keys. Supported: rsa2048, rsa4096, rsa8192, ec256, ec384",
 		},
 		cli.StringFlag{
 			Name:  "path",
@@ -116,7 +130,7 @@ func main() {
 		},
 		cli.StringFlag{
 			Name: "dns",
-			Usage: "Enable the DNS challenge for solving using a provider." +
+			Usage: "Solve a DNS challenge using the specified provider. Disables all other challenges." +
 				"\n\tCredentials for providers have to be passed through environment variables." +
 				"\n\tFor a more detailed explanation of the parameters, please see the online docs." +
 				"\n\tValid providers:" +
@@ -124,7 +138,7 @@ func main() {
 				"\n\tdigitalocean: DO_AUTH_TOKEN" +
 				"\n\tdnsimple: DNSIMPLE_EMAIL, DNSIMPLE_API_KEY" +
 				"\n\troute53: AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_REGION" +
-				"\n\trfc2136: RFC2136_TSIG_KEY, RFC2136_TSIG_SECRET, RFC2136_NAMESERVER, RFC2136_ZONE" +
+				"\n\trfc2136: RFC2136_TSIG_KEY, RFC2136_TSIG_SECRET, RFC2136_TSIG_ALGORITHM, RFC2136_NAMESERVER" +
 				"\n\tmanual: none",
 		},
 	}
diff --git a/cli_handlers.go b/cli_handlers.go
index efd9e368..ab11d11d 100644
--- a/cli_handlers.go
+++ b/cli_handlers.go
@@ -11,6 +11,11 @@ import (
 
 	"github.com/codegangsta/cli"
 	"github.com/xenolf/lego/acme"
+	"github.com/xenolf/lego/providers/dns/cloudflare"
+	"github.com/xenolf/lego/providers/dns/digitalocean"
+	"github.com/xenolf/lego/providers/dns/dnsimple"
+	"github.com/xenolf/lego/providers/dns/rfc2136"
+	"github.com/xenolf/lego/providers/dns/route53"
 )
 
 func checkFolder(path string) error {
@@ -23,7 +28,7 @@ func checkFolder(path string) error {
 func setup(c *cli.Context) (*Configuration, *Account, *acme.Client) {
 	err := checkFolder(c.GlobalString("path"))
 	if err != nil {
-		logger().Fatalf("Cound not check/create path: %s", err.Error())
+		logger().Fatalf("Could not check/create path: %s", err.Error())
 	}
 
 	conf := NewConfiguration(c)
@@ -34,7 +39,12 @@ func setup(c *cli.Context) (*Configuration, *Account, *acme.Client) {
 	//TODO: move to account struct? Currently MUST pass email.
 	acc := NewAccount(c.GlobalString("email"), conf)
 
-	client, err := acme.NewClient(c.GlobalString("server"), acc, conf.RsaBits())
+	keyType, err := conf.KeyType()
+	if err != nil {
+		logger().Fatal(err.Error())
+	}
+
+	client, err := acme.NewClient(c.GlobalString("server"), acc, keyType)
 	if err != nil {
 		logger().Fatalf("Could not create client: %s", err.Error())
 	}
@@ -52,10 +62,16 @@ func setup(c *cli.Context) (*Configuration, *Account, *acme.Client) {
 		client.SetChallengeProvider(acme.HTTP01, provider)
 	}
 	if c.GlobalIsSet("http") {
+		if strings.Index(c.GlobalString("http"), ":") == -1 {
+			logger().Fatalf("The --http switch only accepts interface:port or :port for its argument.")
+		}
 		client.SetHTTPAddress(c.GlobalString("http"))
 	}
 
 	if c.GlobalIsSet("tls") {
+		if strings.Index(c.GlobalString("tls"), ":") == -1 {
+			logger().Fatalf("The --tls switch only accepts interface:port or :port for its argument.")
+		}
 		client.SetTLSAddress(c.GlobalString("tls"))
 	}
 
@@ -64,23 +80,23 @@ func setup(c *cli.Context) (*Configuration, *Account, *acme.Client) {
 		var provider acme.ChallengeProvider
 		switch c.GlobalString("dns") {
 		case "cloudflare":
-			provider, err = acme.NewDNSProviderCloudFlare("", "")
+			provider, err = cloudflare.NewDNSProvider("", "")
 		case "digitalocean":
 			authToken := os.Getenv("DO_AUTH_TOKEN")
 
-			provider, err = acme.NewDNSProviderDigitalOcean(authToken)
+			provider, err = digitalocean.NewDNSProvider(authToken)
 		case "dnsimple":
-			provider, err = acme.NewDNSProviderDNSimple("", "")
+			provider, err = dnsimple.NewDNSProvider("", "")
 		case "route53":
 			awsRegion := os.Getenv("AWS_REGION")
-			provider, err = acme.NewDNSProviderRoute53("", "", awsRegion)
+			provider, err = route53.NewDNSProvider("", "", awsRegion)
 		case "rfc2136":
 			nameserver := os.Getenv("RFC2136_NAMESERVER")
-			zone := os.Getenv("RFC2136_ZONE")
+			tsigAlgorithm := os.Getenv("RFC2136_TSIG_ALGORITHM")
 			tsigKey := os.Getenv("RFC2136_TSIG_KEY")
 			tsigSecret := os.Getenv("RFC2136_TSIG_SECRET")
 
-			provider, err = acme.NewDNSProviderRFC2136(nameserver, zone, tsigKey, tsigSecret)
+			provider, err = rfc2136.NewDNSProvider(nameserver, tsigAlgorithm, tsigKey, tsigSecret)
 		case "manual":
 			provider, err = acme.NewDNSProviderManual()
 		}
@@ -90,6 +106,10 @@ func setup(c *cli.Context) (*Configuration, *Account, *acme.Client) {
 		}
 
 		client.SetChallengeProvider(acme.DNS01, provider)
+
+		// --dns=foo indicates that the user specifically want to do a DNS challenge
+		// infer that the user also wants to exclude all other challenges
+		client.ExcludeChallenges([]acme.Challenge{acme.HTTP01, acme.TLSSNI01})
 	}
 
 	return conf, acc, client
@@ -123,6 +143,47 @@ func saveCertRes(certRes acme.CertificateResource, conf *Configuration) {
 	}
 }
 
+func handleTOS(c *cli.Context, client *acme.Client, acc *Account) {
+	// Check for a global accept override
+	if c.GlobalBool("accept-tos") {
+		err := client.AgreeToTOS()
+		if err != nil {
+			logger().Fatalf("Could not agree to TOS: %s", err.Error())
+		}
+
+		acc.Save()
+		return
+	}
+
+	reader := bufio.NewReader(os.Stdin)
+	logger().Printf("Please review the TOS at %s", acc.Registration.TosURL)
+
+	for {
+		logger().Println("Do you accept the TOS? Y/n")
+		text, err := reader.ReadString('\n')
+		if err != nil {
+			logger().Fatalf("Could not read from console: %s", err.Error())
+		}
+
+		text = strings.Trim(text, "\r\n")
+
+		if text == "n" {
+			logger().Fatal("You did not accept the TOS. Unable to proceed.")
+		}
+
+		if text == "Y" || text == "y" || text == "" {
+			err = client.AgreeToTOS()
+			if err != nil {
+				logger().Fatalf("Could not agree to TOS: %s", err.Error())
+			}
+			acc.Save()
+			break
+		}
+
+		logger().Println("Your input was invalid. Please answer with one of Y/y, n or by pressing enter.")
+	}
+}
+
 func run(c *cli.Context) {
 	conf, acc, client := setup(c)
 	if acc.Registration == nil {
@@ -145,41 +206,16 @@ func run(c *cli.Context) {
 
 	}
 
+	// If the agreement URL is empty, the account still needs to accept the LE TOS.
 	if acc.Registration.Body.Agreement == "" {
-		reader := bufio.NewReader(os.Stdin)
-		logger().Printf("Please review the TOS at %s", acc.Registration.TosURL)
-
-		for {
-			logger().Println("Do you accept the TOS? Y/n")
-			text, err := reader.ReadString('\n')
-			if err != nil {
-				logger().Fatalf("Could not read from console -> %s", err.Error())
-			}
-
-			text = strings.Trim(text, "\r\n")
-
-			if text == "n" {
-				logger().Fatal("You did not accept the TOS. Unable to proceed.")
-			}
-
-			if text == "Y" || text == "y" || text == "" {
-				err = client.AgreeToTOS()
-				if err != nil {
-					logger().Fatalf("Could not agree to tos -> %s", err)
-				}
-				acc.Save()
-				break
-			}
-
-			logger().Println("Your input was invalid. Please answer with one of Y/y, n or by pressing enter.")
-		}
+		handleTOS(c, client, acc)
 	}
 
 	if len(c.GlobalStringSlice("domains")) == 0 {
 		logger().Fatal("Please specify --domains or -d")
 	}
 
-	cert, failures := client.ObtainCertificate(c.GlobalStringSlice("domains"), true, nil)
+	cert, failures := client.ObtainCertificate(c.GlobalStringSlice("domains"), !c.Bool("no-bundle"), nil)
 	if len(failures) > 0 {
 		for k, v := range failures {
 			logger().Printf("[%s] Could not obtain certificates\n\t%s", k, v.Error())
@@ -193,7 +229,7 @@ func run(c *cli.Context) {
 
 	err := checkFolder(conf.CertPath())
 	if err != nil {
-		logger().Fatalf("Cound not check/create path: %s", err.Error())
+		logger().Fatalf("Could not check/create path: %s", err.Error())
 	}
 
 	saveCertRes(cert, conf)
@@ -205,7 +241,7 @@ func revoke(c *cli.Context) {
 
 	err := checkFolder(conf.CertPath())
 	if err != nil {
-		logger().Fatalf("Cound not check/create path: %s", err.Error())
+		logger().Fatalf("Could not check/create path: %s", err.Error())
 	}
 
 	for _, domain := range c.GlobalStringSlice("domains") {
@@ -276,7 +312,7 @@ func renew(c *cli.Context) {
 
 	certRes.Certificate = certBytes
 
-	newCert, err := client.RenewCertificate(certRes, true)
+	newCert, err := client.RenewCertificate(certRes, !c.Bool("no-bundle"))
 	if err != nil {
 		logger().Fatalf("%s", err.Error())
 	}
diff --git a/configuration.go b/configuration.go
index 503510f8..a437fd56 100644
--- a/configuration.go
+++ b/configuration.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"net/url"
 	"os"
 	"path"
@@ -20,11 +21,25 @@ func NewConfiguration(c *cli.Context) *Configuration {
 	return &Configuration{context: c}
 }
 
-// RsaBits returns the current set RSA bit length for private keys
-func (c *Configuration) RsaBits() int {
-	return c.context.GlobalInt("rsa-key-size")
+// KeyType the type from which private keys should be generated
+func (c *Configuration) KeyType() (acme.KeyType, error) {
+	switch strings.ToUpper(c.context.GlobalString("key-type")) {
+	case "RSA2048":
+		return acme.RSA2048, nil
+	case "RSA4096":
+		return acme.RSA4096, nil
+	case "RSA8192":
+		return acme.RSA8192, nil
+	case "EC256":
+		return acme.EC256, nil
+	case "EC384":
+		return acme.EC384, nil
+	}
+
+	return "", fmt.Errorf("Unsupported KeyType: %s", c.context.GlobalString("key-type"))
 }
 
+// ExcludedSolvers is a list of solvers that are to be excluded.
 func (c *Configuration) ExcludedSolvers() (cc []acme.Challenge) {
 	for _, s := range c.context.GlobalStringSlice("exclude") {
 		cc = append(cc, acme.Challenge(s))
@@ -39,6 +54,7 @@ func (c *Configuration) ServerPath() string {
 	return strings.Replace(srvStr, "/", string(os.PathSeparator), -1)
 }
 
+// CertPath gets the path for certificates.
 func (c *Configuration) CertPath() string {
 	return path.Join(c.context.GlobalString("path"), "certificates")
 }
@@ -54,7 +70,7 @@ func (c *Configuration) AccountPath(acc string) string {
 	return path.Join(c.AccountsPath(), acc)
 }
 
-// AccountPath returns the OS dependent path to the keys of a particular account
+// AccountKeysPath returns the OS dependent path to the keys of a particular account
 func (c *Configuration) AccountKeysPath(acc string) string {
 	return path.Join(c.AccountPath(acc), "keys")
 }
diff --git a/crypto.go b/crypto.go
index 3644ed99..8b23e2fc 100644
--- a/crypto.go
+++ b/crypto.go
@@ -1,21 +1,30 @@
 package main
 
 import (
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/elliptic"
 	"crypto/rand"
-	"crypto/rsa"
 	"crypto/x509"
 	"encoding/pem"
+	"errors"
 	"io/ioutil"
 	"os"
 )
 
-func generateRsaKey(length int, file string) (*rsa.PrivateKey, error) {
-	privateKey, err := rsa.GenerateKey(rand.Reader, length)
+func generatePrivateKey(file string) (crypto.PrivateKey, error) {
+
+	privateKey, err := ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
 	if err != nil {
 		return nil, err
 	}
 
-	pemKey := pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(privateKey)}
+	keyBytes, err := x509.MarshalECPrivateKey(privateKey)
+	if err != nil {
+		return nil, err
+	}
+
+	pemKey := pem.Block{Type: "EC PRIVATE KEY", Bytes: keyBytes}
 
 	certOut, err := os.Create(file)
 	if err != nil {
@@ -28,12 +37,20 @@ func generateRsaKey(length int, file string) (*rsa.PrivateKey, error) {
 	return privateKey, nil
 }
 
-func loadRsaKey(file string) (*rsa.PrivateKey, error) {
+func loadPrivateKey(file string) (crypto.PrivateKey, error) {
 	keyBytes, err := ioutil.ReadFile(file)
 	if err != nil {
 		return nil, err
 	}
 
 	keyBlock, _ := pem.Decode(keyBytes)
-	return x509.ParsePKCS1PrivateKey(keyBlock.Bytes)
+
+	switch keyBlock.Type {
+	case "RSA PRIVATE KEY":
+		return x509.ParsePKCS1PrivateKey(keyBlock.Bytes)
+	case "EC PRIVATE KEY":
+		return x509.ParseECPrivateKey(keyBlock.Bytes)
+	}
+
+	return nil, errors.New("Unknown private key type.")
 }
diff --git a/providers/dns/cloudflare/cloudflare.go b/providers/dns/cloudflare/cloudflare.go
new file mode 100644
index 00000000..307cc4ef
--- /dev/null
+++ b/providers/dns/cloudflare/cloudflare.go
@@ -0,0 +1,212 @@
+// Package cloudflare implements a DNS provider for solving the DNS-01 challenge using cloudflare DNS.
+package cloudflare
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/xenolf/lego/acme"
+)
+
+// CloudFlareAPIURL represents the API endpoint to call.
+// TODO: Unexport?
+const CloudFlareAPIURL = "https://api.cloudflare.com/client/v4"
+
+// DNSProvider is an implementation of the acme.ChallengeProvider interface
+type DNSProvider struct {
+	authEmail string
+	authKey   string
+}
+
+// NewDNSProvider returns a DNSProvider instance with a configured cloudflare client.
+// Credentials can either be passed as arguments or through CLOUDFLARE_EMAIL and CLOUDFLARE_API_KEY env vars.
+func NewDNSProvider(cloudflareEmail, cloudflareKey string) (*DNSProvider, error) {
+	if cloudflareEmail == "" || cloudflareKey == "" {
+		cloudflareEmail, cloudflareKey = cloudflareEnvAuth()
+		if cloudflareEmail == "" || cloudflareKey == "" {
+			return nil, fmt.Errorf("CloudFlare credentials missing")
+		}
+	}
+
+	return &DNSProvider{
+		authEmail: cloudflareEmail,
+		authKey:   cloudflareKey,
+	}, nil
+}
+
+// Present creates a TXT record to fulfil the dns-01 challenge
+func (c *DNSProvider) Present(domain, token, keyAuth string) error {
+	fqdn, value, _ := acme.DNS01Record(domain, keyAuth)
+	zoneID, err := c.getHostedZoneID(fqdn)
+	if err != nil {
+		return err
+	}
+
+	rec := cloudFlareRecord{
+		Type:    "TXT",
+		Name:    acme.UnFqdn(fqdn),
+		Content: value,
+		TTL:     120,
+	}
+
+	body, err := json.Marshal(rec)
+	if err != nil {
+		return err
+	}
+
+	_, err = c.makeRequest("POST", fmt.Sprintf("/zones/%s/dns_records", zoneID), bytes.NewReader(body))
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// CleanUp removes the TXT record matching the specified parameters
+func (c *DNSProvider) CleanUp(domain, token, keyAuth string) error {
+	fqdn, _, _ := acme.DNS01Record(domain, keyAuth)
+
+	record, err := c.findTxtRecord(fqdn)
+	if err != nil {
+		return err
+	}
+
+	_, err = c.makeRequest("DELETE", fmt.Sprintf("/zones/%s/dns_records/%s", record.ZoneID, record.ID), nil)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c *DNSProvider) getHostedZoneID(fqdn string) (string, error) {
+	// HostedZone represents a CloudFlare DNS zone
+	type HostedZone struct {
+		ID   string `json:"id"`
+		Name string `json:"name"`
+	}
+
+	result, err := c.makeRequest("GET", "/zones?per_page=1000", nil)
+	if err != nil {
+		return "", err
+	}
+
+	var zones []HostedZone
+	err = json.Unmarshal(result, &zones)
+	if err != nil {
+		return "", err
+	}
+
+	var hostedZone HostedZone
+	for _, zone := range zones {
+		name := acme.ToFqdn(zone.Name)
+		if strings.HasSuffix(fqdn, name) {
+			if len(zone.Name) > len(hostedZone.Name) {
+				hostedZone = zone
+			}
+		}
+	}
+	if hostedZone.ID == "" {
+		return "", fmt.Errorf("No matching CloudFlare zone found for %s", fqdn)
+	}
+
+	return hostedZone.ID, nil
+}
+
+func (c *DNSProvider) findTxtRecord(fqdn string) (*cloudFlareRecord, error) {
+	zoneID, err := c.getHostedZoneID(fqdn)
+	if err != nil {
+		return nil, err
+	}
+
+	result, err := c.makeRequest("GET", fmt.Sprintf("/zones/%s/dns_records?per_page=1000", zoneID), nil)
+	if err != nil {
+		return nil, err
+	}
+
+	var records []cloudFlareRecord
+	err = json.Unmarshal(result, &records)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, rec := range records {
+		if rec.Name == acme.UnFqdn(fqdn) && rec.Type == "TXT" {
+			return &rec, nil
+		}
+	}
+
+	return nil, fmt.Errorf("No existing record found for %s", fqdn)
+}
+
+func (c *DNSProvider) makeRequest(method, uri string, body io.Reader) (json.RawMessage, error) {
+	// APIError contains error details for failed requests
+	type APIError struct {
+		Code    int    `json:"code,omitempty"`
+		Message string `json:"message,omitempty"`
+	}
+
+	// APIResponse represents a response from CloudFlare API
+	type APIResponse struct {
+		Success bool            `json:"success"`
+		Errors  []*APIError     `json:"errors"`
+		Result  json.RawMessage `json:"result"`
+	}
+
+	req, err := http.NewRequest(method, fmt.Sprintf("%s%s", CloudFlareAPIURL, uri), body)
+	if err != nil {
+		return nil, err
+	}
+
+	req.Header.Set("X-Auth-Email", c.authEmail)
+	req.Header.Set("X-Auth-Key", c.authKey)
+	//req.Header.Set("User-Agent", userAgent())
+
+	client := http.Client{Timeout: 30 * time.Second}
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("Error querying API -> %v", err)
+	}
+
+	defer resp.Body.Close()
+
+	var r APIResponse
+	err = json.NewDecoder(resp.Body).Decode(&r)
+	if err != nil {
+		return nil, err
+	}
+
+	if !r.Success {
+		if len(r.Errors) > 0 {
+			return nil, fmt.Errorf("API error -> %d: %s", r.Errors[0].Code, r.Errors[0].Message)
+		}
+		return nil, fmt.Errorf("API error")
+	}
+
+	return r.Result, nil
+}
+
+func cloudflareEnvAuth() (email, apiKey string) {
+	email = os.Getenv("CLOUDFLARE_EMAIL")
+	apiKey = os.Getenv("CLOUDFLARE_API_KEY")
+	if len(email) == 0 || len(apiKey) == 0 {
+		return "", ""
+	}
+	return
+}
+
+// cloudFlareRecord represents a CloudFlare DNS record
+type cloudFlareRecord struct {
+	Name    string `json:"name"`
+	Type    string `json:"type"`
+	Content string `json:"content"`
+	ID      string `json:"id,omitempty"`
+	TTL     int    `json:"ttl,omitempty"`
+	ZoneID  string `json:"zone_id,omitempty"`
+}
diff --git a/acme/dns_challenge_cloudflare_test.go b/providers/dns/cloudflare/cloudflare_test.go
similarity index 73%
rename from acme/dns_challenge_cloudflare_test.go
rename to providers/dns/cloudflare/cloudflare_test.go
index 8b3cd461..63936ce6 100644
--- a/acme/dns_challenge_cloudflare_test.go
+++ b/providers/dns/cloudflare/cloudflare_test.go
@@ -1,4 +1,4 @@
-package acme
+package cloudflare
 
 import (
 	"os"
@@ -29,26 +29,26 @@ func restoreCloudFlareEnv() {
 	os.Setenv("CLOUDFLARE_API_KEY", cflareAPIKey)
 }
 
-func TestNewDNSProviderCloudFlareValid(t *testing.T) {
+func TestNewDNSProviderValid(t *testing.T) {
 	os.Setenv("CLOUDFLARE_EMAIL", "")
 	os.Setenv("CLOUDFLARE_API_KEY", "")
-	_, err := NewDNSProviderCloudFlare("123", "123")
+	_, err := NewDNSProvider("123", "123")
 	assert.NoError(t, err)
 	restoreCloudFlareEnv()
 }
 
-func TestNewDNSProviderCloudFlareValidEnv(t *testing.T) {
+func TestNewDNSProviderValidEnv(t *testing.T) {
 	os.Setenv("CLOUDFLARE_EMAIL", "test@example.com")
 	os.Setenv("CLOUDFLARE_API_KEY", "123")
-	_, err := NewDNSProviderCloudFlare("", "")
+	_, err := NewDNSProvider("", "")
 	assert.NoError(t, err)
 	restoreCloudFlareEnv()
 }
 
-func TestNewDNSProviderCloudFlareMissingCredErr(t *testing.T) {
+func TestNewDNSProviderMissingCredErr(t *testing.T) {
 	os.Setenv("CLOUDFLARE_EMAIL", "")
 	os.Setenv("CLOUDFLARE_API_KEY", "")
-	_, err := NewDNSProviderCloudFlare("", "")
+	_, err := NewDNSProvider("", "")
 	assert.EqualError(t, err, "CloudFlare credentials missing")
 	restoreCloudFlareEnv()
 }
@@ -58,7 +58,7 @@ func TestCloudFlarePresent(t *testing.T) {
 		t.Skip("skipping live test")
 	}
 
-	provider, err := NewDNSProviderCloudFlare(cflareEmail, cflareAPIKey)
+	provider, err := NewDNSProvider(cflareEmail, cflareAPIKey)
 	assert.NoError(t, err)
 
 	err = provider.Present(cflareDomain, "", "123d==")
@@ -70,9 +70,9 @@ func TestCloudFlareCleanUp(t *testing.T) {
 		t.Skip("skipping live test")
 	}
 
-	time.Sleep(time.Second * 1)
+	time.Sleep(time.Second * 2)
 
-	provider, err := NewDNSProviderCloudFlare(cflareEmail, cflareAPIKey)
+	provider, err := NewDNSProvider(cflareEmail, cflareAPIKey)
 	assert.NoError(t, err)
 
 	err = provider.CleanUp(cflareDomain, "", "123d==")
diff --git a/acme/dns_challenge_digitalocean.go b/providers/dns/digitalocean/digitalocean.go
similarity index 83%
rename from acme/dns_challenge_digitalocean.go
rename to providers/dns/digitalocean/digitalocean.go
index 176439e6..fb3e00de 100644
--- a/acme/dns_challenge_digitalocean.go
+++ b/providers/dns/digitalocean/digitalocean.go
@@ -1,4 +1,5 @@
-package acme
+// Package digitalocean implements a DNS provider for solving the DNS-01 challenge using digitalocean DNS.
+package digitalocean
 
 import (
 	"bytes"
@@ -6,28 +7,30 @@ import (
 	"fmt"
 	"net/http"
 	"sync"
+
+	"github.com/xenolf/lego/acme"
 )
 
-// DNSProviderDigitalOcean is an implementation of the DNSProvider interface
+// DNSProvider is an implementation of the acme.ChallengeProvider interface
 // that uses DigitalOcean's REST API to manage TXT records for a domain.
-type DNSProviderDigitalOcean struct {
+type DNSProvider struct {
 	apiAuthToken string
 	recordIDs    map[string]int
 	recordIDsMu  sync.Mutex
 }
 
-// NewDNSProviderDigitalOcean returns a new DNSProviderDigitalOcean instance.
+// NewDNSProvider returns a new DNSProvider instance.
 // apiAuthToken is the personal access token created in the DigitalOcean account
 // control panel, and it will be sent in bearer authorization headers.
-func NewDNSProviderDigitalOcean(apiAuthToken string) (*DNSProviderDigitalOcean, error) {
-	return &DNSProviderDigitalOcean{
+func NewDNSProvider(apiAuthToken string) (*DNSProvider, error) {
+	return &DNSProvider{
 		apiAuthToken: apiAuthToken,
 		recordIDs:    make(map[string]int),
 	}, nil
 }
 
 // Present creates a TXT record using the specified parameters
-func (d *DNSProviderDigitalOcean) Present(domain, token, keyAuth string) error {
+func (d *DNSProvider) Present(domain, token, keyAuth string) error {
 	// txtRecordRequest represents the request body to DO's API to make a TXT record
 	type txtRecordRequest struct {
 		RecordType string `json:"type"`
@@ -45,7 +48,7 @@ func (d *DNSProviderDigitalOcean) Present(domain, token, keyAuth string) error {
 		} `json:"domain_record"`
 	}
 
-	fqdn, value, _ := DNS01Record(domain, keyAuth)
+	fqdn, value, _ := acme.DNS01Record(domain, keyAuth)
 
 	reqURL := fmt.Sprintf("%s/v2/domains/%s/records", digitalOceanBaseURL, domain)
 	reqData := txtRecordRequest{RecordType: "TXT", Name: fqdn, Data: value}
@@ -87,8 +90,8 @@ func (d *DNSProviderDigitalOcean) Present(domain, token, keyAuth string) error {
 }
 
 // CleanUp removes the TXT record matching the specified parameters
-func (d *DNSProviderDigitalOcean) CleanUp(domain, token, keyAuth string) error {
-	fqdn, _, _ := DNS01Record(domain, keyAuth)
+func (d *DNSProvider) CleanUp(domain, token, keyAuth string) error {
+	fqdn, _, _ := acme.DNS01Record(domain, keyAuth)
 
 	// get the record's unique ID from when we created it
 	d.recordIDsMu.Lock()
diff --git a/acme/dns_challenge_digitalocean_test.go b/providers/dns/digitalocean/digitalocean_test.go
similarity index 96%
rename from acme/dns_challenge_digitalocean_test.go
rename to providers/dns/digitalocean/digitalocean_test.go
index cf62090e..8fc383a0 100644
--- a/acme/dns_challenge_digitalocean_test.go
+++ b/providers/dns/digitalocean/digitalocean_test.go
@@ -1,4 +1,4 @@
-package acme
+package digitalocean
 
 import (
 	"fmt"
@@ -53,7 +53,7 @@ func TestDigitalOceanPresent(t *testing.T) {
 	defer mock.Close()
 	digitalOceanBaseURL = mock.URL
 
-	doprov, err := NewDNSProviderDigitalOcean(fakeDigitalOceanAuth)
+	doprov, err := NewDNSProvider(fakeDigitalOceanAuth)
 	if doprov == nil {
 		t.Fatal("Expected non-nil DigitalOcean provider, but was nil")
 	}
@@ -95,7 +95,7 @@ func TestDigitalOceanCleanUp(t *testing.T) {
 	defer mock.Close()
 	digitalOceanBaseURL = mock.URL
 
-	doprov, err := NewDNSProviderDigitalOcean(fakeDigitalOceanAuth)
+	doprov, err := NewDNSProvider(fakeDigitalOceanAuth)
 	if doprov == nil {
 		t.Fatal("Expected non-nil DigitalOcean provider, but was nil")
 	}
diff --git a/acme/dns_challenge_dnsimple.go b/providers/dns/dnsimple/dnsimple.go
similarity index 66%
rename from acme/dns_challenge_dnsimple.go
rename to providers/dns/dnsimple/dnsimple.go
index f22590c7..cde77298 100644
--- a/acme/dns_challenge_dnsimple.go
+++ b/providers/dns/dnsimple/dnsimple.go
@@ -1,4 +1,5 @@
-package acme
+// Package dnsimple implements a DNS provider for solving the DNS-01 challenge using dnsimple DNS.
+package dnsimple
 
 import (
 	"fmt"
@@ -6,34 +7,35 @@ import (
 	"strings"
 
 	"github.com/weppos/dnsimple-go/dnsimple"
+	"github.com/xenolf/lego/acme"
 )
 
-// DNSProviderDNSimple is an implementation of the DNSProvider interface.
-type DNSProviderDNSimple struct {
+// DNSProvider is an implementation of the acme.ChallengeProvider interface.
+type DNSProvider struct {
 	client *dnsimple.Client
 }
 
-// NewDNSProviderDNSimple returns a DNSProviderDNSimple instance with a configured dnsimple client.
+// NewDNSProvider returns a DNSProvider instance with a configured dnsimple client.
 // Authentication is either done using the passed credentials or - when empty - using the environment
 // variables DNSIMPLE_EMAIL and DNSIMPLE_API_KEY.
-func NewDNSProviderDNSimple(dnsimpleEmail, dnsimpleApiKey string) (*DNSProviderDNSimple, error) {
-	if dnsimpleEmail == "" || dnsimpleApiKey == "" {
-		dnsimpleEmail, dnsimpleApiKey = dnsimpleEnvAuth()
-		if dnsimpleEmail == "" || dnsimpleApiKey == "" {
+func NewDNSProvider(dnsimpleEmail, dnsimpleAPIKey string) (*DNSProvider, error) {
+	if dnsimpleEmail == "" || dnsimpleAPIKey == "" {
+		dnsimpleEmail, dnsimpleAPIKey = dnsimpleEnvAuth()
+		if dnsimpleEmail == "" || dnsimpleAPIKey == "" {
 			return nil, fmt.Errorf("DNSimple credentials missing")
 		}
 	}
 
-	c := &DNSProviderDNSimple{
-		client: dnsimple.NewClient(dnsimpleApiKey, dnsimpleEmail),
+	c := &DNSProvider{
+		client: dnsimple.NewClient(dnsimpleAPIKey, dnsimpleEmail),
 	}
 
 	return c, nil
 }
 
 // Present creates a TXT record to fulfil the dns-01 challenge.
-func (c *DNSProviderDNSimple) Present(domain, token, keyAuth string) error {
-	fqdn, value, ttl := DNS01Record(domain, keyAuth)
+func (c *DNSProvider) Present(domain, token, keyAuth string) error {
+	fqdn, value, ttl := acme.DNS01Record(domain, keyAuth)
 
 	zoneID, zoneName, err := c.getHostedZone(domain)
 	if err != nil {
@@ -50,8 +52,8 @@ func (c *DNSProviderDNSimple) Present(domain, token, keyAuth string) error {
 }
 
 // CleanUp removes the TXT record matching the specified parameters.
-func (c *DNSProviderDNSimple) CleanUp(domain, token, keyAuth string) error {
-	fqdn, _, _ := DNS01Record(domain, keyAuth)
+func (c *DNSProvider) CleanUp(domain, token, keyAuth string) error {
+	fqdn, _, _ := acme.DNS01Record(domain, keyAuth)
 
 	records, err := c.findTxtRecords(domain, fqdn)
 	if err != nil {
@@ -67,7 +69,7 @@ func (c *DNSProviderDNSimple) CleanUp(domain, token, keyAuth string) error {
 	return nil
 }
 
-func (c *DNSProviderDNSimple) getHostedZone(domain string) (string, string, error) {
+func (c *DNSProvider) getHostedZone(domain string) (string, string, error) {
 	domains, _, err := c.client.Domains.List()
 	if err != nil {
 		return "", "", fmt.Errorf("DNSimple API call failed: %v", err)
@@ -88,7 +90,7 @@ func (c *DNSProviderDNSimple) getHostedZone(domain string) (string, string, erro
 	return fmt.Sprintf("%v", hostedDomain.Id), hostedDomain.Name, nil
 }
 
-func (c *DNSProviderDNSimple) findTxtRecords(domain, fqdn string) ([]dnsimple.Record, error) {
+func (c *DNSProvider) findTxtRecords(domain, fqdn string) ([]dnsimple.Record, error) {
 	zoneID, zoneName, err := c.getHostedZone(domain)
 	if err != nil {
 		return nil, err
@@ -110,7 +112,7 @@ func (c *DNSProviderDNSimple) findTxtRecords(domain, fqdn string) ([]dnsimple.Re
 	return records, nil
 }
 
-func (c *DNSProviderDNSimple) newTxtRecord(zone, fqdn, value string, ttl int) *dnsimple.Record {
+func (c *DNSProvider) newTxtRecord(zone, fqdn, value string, ttl int) *dnsimple.Record {
 	name := c.extractRecordName(fqdn, zone)
 
 	return &dnsimple.Record{
@@ -121,8 +123,8 @@ func (c *DNSProviderDNSimple) newTxtRecord(zone, fqdn, value string, ttl int) *d
 	}
 }
 
-func (c *DNSProviderDNSimple) extractRecordName(fqdn, domain string) string {
-	name := unFqdn(fqdn)
+func (c *DNSProvider) extractRecordName(fqdn, domain string) string {
+	name := acme.UnFqdn(fqdn)
 	if idx := strings.Index(name, "."+domain); idx != -1 {
 		return name[:idx]
 	}
diff --git a/acme/dns_challenge_dnsimple_test.go b/providers/dns/dnsimple/dnsimple_test.go
similarity index 75%
rename from acme/dns_challenge_dnsimple_test.go
rename to providers/dns/dnsimple/dnsimple_test.go
index 0f51afdd..7cb19fea 100644
--- a/acme/dns_challenge_dnsimple_test.go
+++ b/providers/dns/dnsimple/dnsimple_test.go
@@ -1,4 +1,4 @@
-package acme
+package dnsimple
 
 import (
 	"os"
@@ -29,25 +29,25 @@ func restoreDNSimpleEnv() {
 	os.Setenv("DNSIMPLE_API_KEY", dnsimpleAPIKey)
 }
 
-func TestNewDNSProviderDNSimpleValid(t *testing.T) {
+func TestNewDNSProviderValid(t *testing.T) {
 	os.Setenv("DNSIMPLE_EMAIL", "")
 	os.Setenv("DNSIMPLE_API_KEY", "")
-	_, err := NewDNSProviderDNSimple("example@example.com", "123")
+	_, err := NewDNSProvider("example@example.com", "123")
 	assert.NoError(t, err)
 	restoreDNSimpleEnv()
 }
-func TestNewDNSProviderDNSimpleValidEnv(t *testing.T) {
+func TestNewDNSProviderValidEnv(t *testing.T) {
 	os.Setenv("DNSIMPLE_EMAIL", "example@example.com")
 	os.Setenv("DNSIMPLE_API_KEY", "123")
-	_, err := NewDNSProviderDNSimple("", "")
+	_, err := NewDNSProvider("", "")
 	assert.NoError(t, err)
 	restoreDNSimpleEnv()
 }
 
-func TestNewDNSProviderDNSimpleMissingCredErr(t *testing.T) {
+func TestNewDNSProviderMissingCredErr(t *testing.T) {
 	os.Setenv("DNSIMPLE_EMAIL", "")
 	os.Setenv("DNSIMPLE_API_KEY", "")
-	_, err := NewDNSProviderDNSimple("", "")
+	_, err := NewDNSProvider("", "")
 	assert.EqualError(t, err, "DNSimple credentials missing")
 	restoreDNSimpleEnv()
 }
@@ -57,7 +57,7 @@ func TestLiveDNSimplePresent(t *testing.T) {
 		t.Skip("skipping live test")
 	}
 
-	provider, err := NewDNSProviderDNSimple(dnsimpleEmail, dnsimpleAPIKey)
+	provider, err := NewDNSProvider(dnsimpleEmail, dnsimpleAPIKey)
 	assert.NoError(t, err)
 
 	err = provider.Present(dnsimpleDomain, "", "123d==")
@@ -71,7 +71,7 @@ func TestLiveDNSimpleCleanUp(t *testing.T) {
 
 	time.Sleep(time.Second * 1)
 
-	provider, err := NewDNSProviderDNSimple(cflareEmail, cflareAPIKey)
+	provider, err := NewDNSProvider(dnsimpleEmail, dnsimpleAPIKey)
 	assert.NoError(t, err)
 
 	err = provider.CleanUp(dnsimpleDomain, "", "123d==")
diff --git a/providers/dns/rfc2136/rfc2136.go b/providers/dns/rfc2136/rfc2136.go
new file mode 100644
index 00000000..3d32409b
--- /dev/null
+++ b/providers/dns/rfc2136/rfc2136.go
@@ -0,0 +1,108 @@
+// Package rfc2136 implements a DNS provider for solving the DNS-01 challenge using the rfc2136 dynamic update.
+package rfc2136
+
+import (
+	"fmt"
+	"net"
+	"strings"
+	"time"
+
+	"github.com/miekg/dns"
+	"github.com/xenolf/lego/acme"
+)
+
+// DNSProvider is an implementation of the acme.ChallengeProvider interface that
+// uses dynamic DNS updates (RFC 2136) to create TXT records on a nameserver.
+type DNSProvider struct {
+	nameserver    string
+	tsigAlgorithm string
+	tsigKey       string
+	tsigSecret    string
+}
+
+// NewDNSProvider returns a new DNSProvider instance.
+// To disable TSIG authentication 'tsigAlgorithm, 'tsigKey' and 'tsigSecret' must be set to the empty string.
+// 'nameserver' must be a network address in the the form "host" or "host:port".
+func NewDNSProvider(nameserver, tsigAlgorithm, tsigKey, tsigSecret string) (*DNSProvider, error) {
+	// Append the default DNS port if none is specified.
+	if _, _, err := net.SplitHostPort(nameserver); err != nil {
+		if strings.Contains(err.Error(), "missing port") {
+			nameserver = net.JoinHostPort(nameserver, "53")
+		} else {
+			return nil, err
+		}
+	}
+	d := &DNSProvider{
+		nameserver: nameserver,
+	}
+	if tsigAlgorithm == "" {
+		tsigAlgorithm = dns.HmacMD5
+	}
+	d.tsigAlgorithm = tsigAlgorithm
+	if len(tsigKey) > 0 && len(tsigSecret) > 0 {
+		d.tsigKey = tsigKey
+		d.tsigSecret = tsigSecret
+	}
+
+	return d, nil
+}
+
+// Present creates a TXT record using the specified parameters
+func (r *DNSProvider) Present(domain, token, keyAuth string) error {
+	fqdn, value, ttl := acme.DNS01Record(domain, keyAuth)
+	return r.changeRecord("INSERT", fqdn, value, ttl)
+}
+
+// CleanUp removes the TXT record matching the specified parameters
+func (r *DNSProvider) CleanUp(domain, token, keyAuth string) error {
+	fqdn, value, ttl := acme.DNS01Record(domain, keyAuth)
+	return r.changeRecord("REMOVE", fqdn, value, ttl)
+}
+
+func (r *DNSProvider) changeRecord(action, fqdn, value string, ttl int) error {
+	// Find the zone for the given fqdn
+	zone, err := acme.FindZoneByFqdn(fqdn, r.nameserver)
+	if err != nil {
+		return err
+	}
+
+	// Create RR
+	rr := new(dns.TXT)
+	rr.Hdr = dns.RR_Header{Name: fqdn, Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: uint32(ttl)}
+	rr.Txt = []string{value}
+	rrs := []dns.RR{rr}
+
+	// Create dynamic update packet
+	m := new(dns.Msg)
+	m.SetUpdate(zone)
+	switch action {
+	case "INSERT":
+		// Always remove old challenge left over from who knows what.
+		m.RemoveRRset(rrs)
+		m.Insert(rrs)
+	case "REMOVE":
+		m.Remove(rrs)
+	default:
+		return fmt.Errorf("Unexpected action: %s", action)
+	}
+
+	// Setup client
+	c := new(dns.Client)
+	c.SingleInflight = true
+	// TSIG authentication / msg signing
+	if len(r.tsigKey) > 0 && len(r.tsigSecret) > 0 {
+		m.SetTsig(dns.Fqdn(r.tsigKey), r.tsigAlgorithm, 300, time.Now().Unix())
+		c.TsigSecret = map[string]string{dns.Fqdn(r.tsigKey): r.tsigSecret}
+	}
+
+	// Send the query
+	reply, _, err := c.Exchange(m, r.nameserver)
+	if err != nil {
+		return fmt.Errorf("DNS update failed: %v", err)
+	}
+	if reply != nil && reply.Rcode != dns.RcodeSuccess {
+		return fmt.Errorf("DNS update failed. Server replied: %s", dns.RcodeToString[reply.Rcode])
+	}
+
+	return nil
+}
diff --git a/acme/dns_challenge_rfc2136_test.go b/providers/dns/rfc2136/rfc2136_test.go
similarity index 74%
rename from acme/dns_challenge_rfc2136_test.go
rename to providers/dns/rfc2136/rfc2136_test.go
index f9fc5dea..2aa8aa22 100644
--- a/acme/dns_challenge_rfc2136_test.go
+++ b/providers/dns/rfc2136/rfc2136_test.go
@@ -1,7 +1,8 @@
-package acme
+package rfc2136
 
 import (
 	"bytes"
+	"fmt"
 	"net"
 	"strings"
 	"sync"
@@ -9,6 +10,7 @@ import (
 	"time"
 
 	"github.com/miekg/dns"
+	"github.com/xenolf/lego/acme"
 )
 
 var (
@@ -25,6 +27,7 @@ var (
 var reqChan = make(chan *dns.Msg, 10)
 
 func TestRFC2136CanaryLocalTestServer(t *testing.T) {
+	acme.ClearFqdnCache()
 	dns.HandleFunc("example.com.", serverHandlerHello)
 	defer dns.HandleRemove("example.com.")
 
@@ -48,6 +51,7 @@ func TestRFC2136CanaryLocalTestServer(t *testing.T) {
 }
 
 func TestRFC2136ServerSuccess(t *testing.T) {
+	acme.ClearFqdnCache()
 	dns.HandleFunc(rfc2136TestZone, serverHandlerReturnSuccess)
 	defer dns.HandleRemove(rfc2136TestZone)
 
@@ -57,9 +61,9 @@ func TestRFC2136ServerSuccess(t *testing.T) {
 	}
 	defer server.Shutdown()
 
-	provider, err := NewDNSProviderRFC2136(addrstr, rfc2136TestZone, "", "")
+	provider, err := NewDNSProvider(addrstr, "", "", "")
 	if err != nil {
-		t.Fatalf("Expected NewDNSProviderRFC2136() to return no error but the error was -> %v", err)
+		t.Fatalf("Expected NewDNSProvider() to return no error but the error was -> %v", err)
 	}
 	if err := provider.Present(rfc2136TestDomain, "", rfc2136TestKeyAuth); err != nil {
 		t.Errorf("Expected Present() to return no error but the error was -> %v", err)
@@ -67,6 +71,7 @@ func TestRFC2136ServerSuccess(t *testing.T) {
 }
 
 func TestRFC2136ServerError(t *testing.T) {
+	acme.ClearFqdnCache()
 	dns.HandleFunc(rfc2136TestZone, serverHandlerReturnErr)
 	defer dns.HandleRemove(rfc2136TestZone)
 
@@ -76,9 +81,9 @@ func TestRFC2136ServerError(t *testing.T) {
 	}
 	defer server.Shutdown()
 
-	provider, err := NewDNSProviderRFC2136(addrstr, rfc2136TestZone, "", "")
+	provider, err := NewDNSProvider(addrstr, "", "", "")
 	if err != nil {
-		t.Fatalf("Expected NewDNSProviderRFC2136() to return no error but the error was -> %v", err)
+		t.Fatalf("Expected NewDNSProvider() to return no error but the error was -> %v", err)
 	}
 	if err := provider.Present(rfc2136TestDomain, "", rfc2136TestKeyAuth); err == nil {
 		t.Errorf("Expected Present() to return an error but it did not.")
@@ -88,6 +93,7 @@ func TestRFC2136ServerError(t *testing.T) {
 }
 
 func TestRFC2136TsigClient(t *testing.T) {
+	acme.ClearFqdnCache()
 	dns.HandleFunc(rfc2136TestZone, serverHandlerReturnSuccess)
 	defer dns.HandleRemove(rfc2136TestZone)
 
@@ -97,9 +103,9 @@ func TestRFC2136TsigClient(t *testing.T) {
 	}
 	defer server.Shutdown()
 
-	provider, err := NewDNSProviderRFC2136(addrstr, rfc2136TestZone, rfc2136TestTsigKey, rfc2136TestTsigSecret)
+	provider, err := NewDNSProvider(addrstr, "", rfc2136TestTsigKey, rfc2136TestTsigSecret)
 	if err != nil {
-		t.Fatalf("Expected NewDNSProviderRFC2136() to return no error but the error was -> %v", err)
+		t.Fatalf("Expected NewDNSProvider() to return no error but the error was -> %v", err)
 	}
 	if err := provider.Present(rfc2136TestDomain, "", rfc2136TestKeyAuth); err != nil {
 		t.Errorf("Expected Present() to return no error but the error was -> %v", err)
@@ -107,6 +113,7 @@ func TestRFC2136TsigClient(t *testing.T) {
 }
 
 func TestRFC2136ValidUpdatePacket(t *testing.T) {
+	acme.ClearFqdnCache()
 	dns.HandleFunc(rfc2136TestZone, serverHandlerPassBackRequest)
 	defer dns.HandleRemove(rfc2136TestZone)
 
@@ -116,18 +123,11 @@ func TestRFC2136ValidUpdatePacket(t *testing.T) {
 	}
 	defer server.Shutdown()
 
-	rr := new(dns.TXT)
-	rr.Hdr = dns.RR_Header{
-		Name:   rfc2136TestFqdn,
-		Rrtype: dns.TypeTXT,
-		Class:  dns.ClassINET,
-		Ttl:    uint32(rfc2136TestTTL),
-	}
-	rr.Txt = []string{rfc2136TestValue}
-	rrs := make([]dns.RR, 1)
-	rrs[0] = rr
+	txtRR, _ := dns.NewRR(fmt.Sprintf("%s %d IN TXT %s", rfc2136TestFqdn, rfc2136TestTTL, rfc2136TestValue))
+	rrs := []dns.RR{txtRR}
 	m := new(dns.Msg)
-	m.SetUpdate(dns.Fqdn(rfc2136TestZone))
+	m.SetUpdate(rfc2136TestZone)
+	m.RemoveRRset(rrs)
 	m.Insert(rrs)
 	expectstr := m.String()
 	expect, err := m.Pack()
@@ -135,9 +135,9 @@ func TestRFC2136ValidUpdatePacket(t *testing.T) {
 		t.Fatalf("Error packing expect msg: %v", err)
 	}
 
-	provider, err := NewDNSProviderRFC2136(addrstr, rfc2136TestZone, "", "")
+	provider, err := NewDNSProvider(addrstr, "", "", "")
 	if err != nil {
-		t.Fatalf("Expected NewDNSProviderRFC2136() to return no error but the error was -> %v", err)
+		t.Fatalf("Expected NewDNSProvider() to return no error but the error was -> %v", err)
 	}
 
 	if err := provider.Present(rfc2136TestDomain, "", "1234d=="); err != nil {
@@ -198,6 +198,11 @@ func serverHandlerHello(w dns.ResponseWriter, req *dns.Msg) {
 func serverHandlerReturnSuccess(w dns.ResponseWriter, req *dns.Msg) {
 	m := new(dns.Msg)
 	m.SetReply(req)
+	if req.Opcode == dns.OpcodeQuery && req.Question[0].Qtype == dns.TypeSOA && req.Question[0].Qclass == dns.ClassINET {
+		// Return SOA to appease findZoneByFqdn()
+		soaRR, _ := dns.NewRR(fmt.Sprintf("%s %d IN SOA ns1.%s admin.%s 2016022801 28800 7200 2419200 1200", rfc2136TestZone, rfc2136TestTTL, rfc2136TestZone, rfc2136TestZone))
+		m.Answer = []dns.RR{soaRR}
+	}
 
 	if t := req.IsTsig(); t != nil {
 		if w.TsigStatus() == nil {
@@ -218,6 +223,11 @@ func serverHandlerReturnErr(w dns.ResponseWriter, req *dns.Msg) {
 func serverHandlerPassBackRequest(w dns.ResponseWriter, req *dns.Msg) {
 	m := new(dns.Msg)
 	m.SetReply(req)
+	if req.Opcode == dns.OpcodeQuery && req.Question[0].Qtype == dns.TypeSOA && req.Question[0].Qclass == dns.ClassINET {
+		// Return SOA to appease findZoneByFqdn()
+		soaRR, _ := dns.NewRR(fmt.Sprintf("%s %d IN SOA ns1.%s admin.%s 2016022801 28800 7200 2419200 1200", rfc2136TestZone, rfc2136TestTTL, rfc2136TestZone, rfc2136TestZone))
+		m.Answer = []dns.RR{soaRR}
+	}
 
 	if t := req.IsTsig(); t != nil {
 		if w.TsigStatus() == nil {
@@ -227,5 +237,8 @@ func serverHandlerPassBackRequest(w dns.ResponseWriter, req *dns.Msg) {
 	}
 
 	w.WriteMsg(m)
-	reqChan <- req
+	if req.Opcode != dns.OpcodeQuery || req.Question[0].Qtype != dns.TypeSOA || req.Question[0].Qclass != dns.ClassINET {
+		// Only talk back when it is not the SOA RR.
+		reqChan <- req
+	}
 }
diff --git a/acme/dns_challenge_route53.go b/providers/dns/route53/route53.go
similarity index 73%
rename from acme/dns_challenge_route53.go
rename to providers/dns/route53/route53.go
index 9ee77e35..eb1ffdf3 100644
--- a/acme/dns_challenge_route53.go
+++ b/providers/dns/route53/route53.go
@@ -1,4 +1,5 @@
-package acme
+// Package route53 implements a DNS provider for solving the DNS-01 challenge using route53 DNS.
+package route53
 
 import (
 	"fmt"
@@ -7,20 +8,21 @@ import (
 
 	"github.com/mitchellh/goamz/aws"
 	"github.com/mitchellh/goamz/route53"
+	"github.com/xenolf/lego/acme"
 )
 
-// DNSProviderRoute53 is an implementation of the DNSProvider interface
-type DNSProviderRoute53 struct {
+// DNSProvider is an implementation of the acme.ChallengeProvider interface
+type DNSProvider struct {
 	client *route53.Route53
 }
 
-// NewDNSProviderRoute53 returns a DNSProviderRoute53 instance with a configured route53 client.
+// NewDNSProvider returns a DNSProvider instance with a configured route53 client.
 // Authentication is either done using the passed credentials or - when empty - falling back to
-// the customary AWS credential mechanisms, including the file refernced by $AWS_CREDENTIAL_FILE
+// the customary AWS credential mechanisms, including the file referenced by $AWS_CREDENTIAL_FILE
 // (defaulting to $HOME/.aws/credentials) optionally scoped to $AWS_PROFILE, credentials
 // supplied by the environment variables AWS_ACCESS_KEY_ID + AWS_SECRET_ACCESS_KEY [ + AWS_SECURITY_TOKEN ],
 // and finally credentials available via the EC2 instance metadata service.
-func NewDNSProviderRoute53(awsAccessKey, awsSecretKey, awsRegionName string) (*DNSProviderRoute53, error) {
+func NewDNSProvider(awsAccessKey, awsSecretKey, awsRegionName string) (*DNSProvider, error) {
 	region, ok := aws.Regions[awsRegionName]
 	if !ok {
 		return nil, fmt.Errorf("Invalid AWS region name %s", awsRegionName)
@@ -32,35 +34,36 @@ func NewDNSProviderRoute53(awsAccessKey, awsSecretKey, awsRegionName string) (*D
 	//   - uses AWS_ACCESS_KEY_ID + AWS_SECRET_ACCESS_KEY and optionally AWS_SECURITY_TOKEN, if provided
 	//   - uses EC2 instance metadata credentials (http://169.254.169.254/latest/meta-data/…), if available
 	//  ...and otherwise returns an error
-	if auth, err := aws.GetAuth(awsAccessKey, awsSecretKey); err != nil {
+	auth, err := aws.GetAuth(awsAccessKey, awsSecretKey)
+	if err != nil {
 		return nil, err
-	} else {
-		client := route53.New(auth, region)
-		return &DNSProviderRoute53{client: client}, nil
 	}
+
+	client := route53.New(auth, region)
+	return &DNSProvider{client: client}, nil
 }
 
 // Present creates a TXT record using the specified parameters
-func (r *DNSProviderRoute53) Present(domain, token, keyAuth string) error {
-	fqdn, value, ttl := DNS01Record(domain, keyAuth)
+func (r *DNSProvider) Present(domain, token, keyAuth string) error {
+	fqdn, value, ttl := acme.DNS01Record(domain, keyAuth)
 	value = `"` + value + `"`
 	return r.changeRecord("UPSERT", fqdn, value, ttl)
 }
 
 // CleanUp removes the TXT record matching the specified parameters
-func (r *DNSProviderRoute53) CleanUp(domain, token, keyAuth string) error {
-	fqdn, value, ttl := DNS01Record(domain, keyAuth)
+func (r *DNSProvider) CleanUp(domain, token, keyAuth string) error {
+	fqdn, value, ttl := acme.DNS01Record(domain, keyAuth)
 	value = `"` + value + `"`
 	return r.changeRecord("DELETE", fqdn, value, ttl)
 }
 
-func (r *DNSProviderRoute53) changeRecord(action, fqdn, value string, ttl int) error {
+func (r *DNSProvider) changeRecord(action, fqdn, value string, ttl int) error {
 	hostedZoneID, err := r.getHostedZoneID(fqdn)
 	if err != nil {
 		return err
 	}
 	recordSet := newTXTRecordSet(fqdn, value, ttl)
-	update := route53.Change{action, recordSet}
+	update := route53.Change{Action: action, Record: recordSet}
 	changes := []route53.Change{update}
 	req := route53.ChangeResourceRecordSetsRequest{Comment: "Created by Lego", Changes: changes}
 	resp, err := r.client.ChangeResourceRecordSets(hostedZoneID, &req)
@@ -68,7 +71,7 @@ func (r *DNSProviderRoute53) changeRecord(action, fqdn, value string, ttl int) e
 		return err
 	}
 
-	return waitFor(90, func() (bool, error) {
+	return acme.WaitFor(90*time.Second, 5*time.Second, func() (bool, error) {
 		status, err := r.client.GetChange(resp.ChangeInfo.ID)
 		if err != nil {
 			return false, err
@@ -80,7 +83,7 @@ func (r *DNSProviderRoute53) changeRecord(action, fqdn, value string, ttl int) e
 	})
 }
 
-func (r *DNSProviderRoute53) getHostedZoneID(fqdn string) (string, error) {
+func (r *DNSProvider) getHostedZoneID(fqdn string) (string, error) {
 	zones := []route53.HostedZone{}
 	zoneResp, err := r.client.ListHostedZones("", 0)
 	if err != nil {
diff --git a/acme/dns_challenge_route53_test.go b/providers/dns/route53/route53_test.go
similarity index 79%
rename from acme/dns_challenge_route53_test.go
rename to providers/dns/route53/route53_test.go
index 20eb008b..8bb675c3 100644
--- a/acme/dns_challenge_route53_test.go
+++ b/providers/dns/route53/route53_test.go
@@ -1,8 +1,10 @@
-package acme
+package route53
 
 import (
+	"net/http"
 	"os"
 	"testing"
+	"time"
 
 	"github.com/mitchellh/goamz/aws"
 	"github.com/mitchellh/goamz/route53"
@@ -63,9 +65,9 @@ var GetChangeAnswer = `<?xml version="1.0" encoding="UTF-8"?>
 </GetChangeResponse>`
 
 var serverResponseMap = testutil.ResponseMap{
-	"/2013-04-01/hostedzone/":                      testutil.Response{200, nil, ListHostedZonesAnswer},
-	"/2013-04-01/hostedzone/Z2K123214213123/rrset": testutil.Response{200, nil, ChangeResourceRecordSetsAnswer},
-	"/2013-04-01/change/asdf":                      testutil.Response{200, nil, GetChangeAnswer},
+	"/2013-04-01/hostedzone/":                      testutil.Response{Status: 200, Headers: nil, Body: ListHostedZonesAnswer},
+	"/2013-04-01/hostedzone/Z2K123214213123/rrset": testutil.Response{Status: 200, Headers: nil, Body: ChangeResourceRecordSetsAnswer},
+	"/2013-04-01/change/asdf":                      testutil.Response{Status: 200, Headers: nil, Body: GetChangeAnswer},
 }
 
 func init() {
@@ -89,40 +91,49 @@ func makeRoute53TestServer() *testutil.HTTPServer {
 	return testServer
 }
 
-func makeRoute53Provider(server *testutil.HTTPServer) *DNSProviderRoute53 {
-	auth := aws.Auth{"abc", "123", ""}
+func makeRoute53Provider(server *testutil.HTTPServer) *DNSProvider {
+	auth := aws.Auth{AccessKey: "abc", SecretKey: "123", Token: ""}
 	client := route53.NewWithClient(auth, aws.Region{Route53Endpoint: server.URL}, testutil.DefaultClient)
-	return &DNSProviderRoute53{client: client}
+	return &DNSProvider{client: client}
 }
 
-func TestNewDNSProviderRoute53Valid(t *testing.T) {
+func TestNewDNSProviderValid(t *testing.T) {
 	os.Setenv("AWS_ACCESS_KEY_ID", "")
 	os.Setenv("AWS_SECRET_ACCESS_KEY", "")
-	_, err := NewDNSProviderRoute53("123", "123", "us-east-1")
+	_, err := NewDNSProvider("123", "123", "us-east-1")
 	assert.NoError(t, err)
 	restoreRoute53Env()
 }
 
-func TestNewDNSProviderRoute53ValidEnv(t *testing.T) {
+func TestNewDNSProviderValidEnv(t *testing.T) {
 	os.Setenv("AWS_ACCESS_KEY_ID", "123")
 	os.Setenv("AWS_SECRET_ACCESS_KEY", "123")
-	_, err := NewDNSProviderRoute53("", "", "us-east-1")
+	_, err := NewDNSProvider("", "", "us-east-1")
 	assert.NoError(t, err)
 	restoreRoute53Env()
 }
 
-func TestNewDNSProviderRoute53MissingAuthErr(t *testing.T) {
+func TestNewDNSProviderMissingAuthErr(t *testing.T) {
 	os.Setenv("AWS_ACCESS_KEY_ID", "")
 	os.Setenv("AWS_SECRET_ACCESS_KEY", "")
 	os.Setenv("AWS_CREDENTIAL_FILE", "") // in case test machine has this variable set
 	os.Setenv("HOME", "/")               // in case test machine has ~/.aws/credentials
-	_, err := NewDNSProviderRoute53("", "", "us-east-1")
+
+	// The default AWS HTTP client retries three times with a deadline of 10 seconds.
+	// Replace the default HTTP client with one that does not retry and has a low timeout.
+	awsClient := aws.RetryingClient
+	aws.RetryingClient = &http.Client{Timeout: time.Millisecond}
+
+	_, err := NewDNSProvider("", "", "us-east-1")
 	assert.EqualError(t, err, "No valid AWS authentication found")
 	restoreRoute53Env()
+
+	// restore default AWS HTTP client
+	aws.RetryingClient = awsClient
 }
 
-func TestNewDNSProviderRoute53InvalidRegionErr(t *testing.T) {
-	_, err := NewDNSProviderRoute53("123", "123", "us-east-3")
+func TestNewDNSProviderInvalidRegionErr(t *testing.T) {
+	_, err := NewDNSProvider("123", "123", "us-east-3")
 	assert.EqualError(t, err, "Invalid AWS region name us-east-3")
 }