diff --git a/acme/jws.go b/acme/jws.go
index c5c496a1..96f7ae9e 100644
--- a/acme/jws.go
+++ b/acme/jws.go
@@ -4,11 +4,10 @@ import (
 	"bytes"
 	"crypto/ecdsa"
 	"crypto/rsa"
-	"errors"
 	"fmt"
 	"net/http"
 
-	"github.com/square/go-jose"
+	"github.com/letsencrypt/go-jose"
 )
 
 type jws struct {
@@ -16,15 +15,10 @@ type jws struct {
 	nonces  []string
 }
 
-func keyAsJWK(key interface{}) *jose.JsonWebKey {
-	switch k := key.(type) {
-	case *ecdsa.PublicKey:
-		return &jose.JsonWebKey{Key: k, Algorithm: "EC"}
-	case *rsa.PublicKey:
-		return &jose.JsonWebKey{Key: k, Algorithm: "RSA"}
-
-	default:
-		return nil
+func keyAsJWK(key *ecdsa.PublicKey) jose.JsonWebKey {
+	return jose.JsonWebKey{
+		Key:       key,
+		Algorithm: "EC",
 	}
 }
 
@@ -58,9 +52,8 @@ func (j *jws) signContent(content []byte) (*jose.JsonWebSignature, error) {
 	if err != nil {
 		return nil, err
 	}
-	signer.SetNonceSource(j)
 
-	signed, err := signer.Sign(content)
+	signed, err := signer.Sign(content, j.consumeNonce())
 	if err != nil {
 		return nil, err
 	}
@@ -86,12 +79,12 @@ func (j *jws) getNonce(url string) error {
 	return j.getNonceFromResponse(resp)
 }
 
-func (j *jws) Nonce() (string, error) {
+func (j *jws) consumeNonce() string {
 	nonce := ""
 	if len(j.nonces) == 0 {
-		return nonce, errors.New("No nonce available.")
+		return nonce
 	}
 
 	nonce, j.nonces = j.nonces[len(j.nonces)-1], j.nonces[:len(j.nonces)-1]
-	return nonce, nil
+	return nonce
 }
diff --git a/acme/messages.go b/acme/messages.go
index 857ec32a..948a86cc 100644
--- a/acme/messages.go
+++ b/acme/messages.go
@@ -3,7 +3,7 @@ package acme
 import (
 	"time"
 
-	"github.com/square/go-jose"
+	"github.com/letsencrypt/go-jose"
 )
 
 type directory struct {