diff --git a/reference/reference.go b/reference/reference.go
index abf4d70d..17e87d9b 100644
--- a/reference/reference.go
+++ b/reference/reference.go
@@ -7,11 +7,13 @@
 //
 //	// repository.go
 //	repository			:= hostname ['/' component]+
-//	hostname 			:= component [':' port-number]
+//	hostname 			:= hostcomponent [':' port-number]
 //	component			:= alpha-numeric [separator alpha-numeric]*
+//	hostcomponent                   := [hostpart '.']* hostpart
 // 	alpha-numeric			:= /[a-zA-Z0-9]+/
-//	separator			:= /[._-]/
+//	separator			:= /[_-]/
 //	port-number			:= /[0-9]+/
+//	hostpart                        := /([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9])/
 //
 //	// tag.go
 //	tag                             := /[\w][\w.-]{0,127}/
@@ -20,167 +22,224 @@
 //	digest                          := digest-algorithm ":" digest-hex
 //	digest-algorithm                := digest-algorithm-component [ digest-algorithm-separator digest-algorithm-component ]
 //	digest-algorithm-separator      := /[+.-_]/
-//	digest-algorithm-component      := /[A-Za-z]/ /[A-Za-z0-9]*/
-//	digest-hex                      := /[A-Za-z0-9_-]+/ ; supports hex bytes or url safe base64
+//	digest-algorithm-component      := /[A-Za-z][A-Za-z0-9]*/
+//	digest-hex                      := /[0-9a-fA-F]{32,}/ ; Atleast 128 bit digest value
 package reference
 
 import (
 	"errors"
-	"regexp"
+	"fmt"
 
 	"github.com/docker/distribution/digest"
 )
 
-// ErrReferenceInvalidFormat represents an error while trying to parse a string as a reference.
-var ErrReferenceInvalidFormat = errors.New("invalid reference format")
+const (
+	// NameTotalLengthMax is the maximum total number of characters in a repository name.
+	NameTotalLengthMax = 255
+)
 
-// Reference abstracts types that reference images in a certain way.
+var (
+	// ErrReferenceInvalidFormat represents an error while trying to parse a string as a reference.
+	ErrReferenceInvalidFormat = errors.New("invalid reference format")
+
+	// ErrNameEmpty is returned for empty, invalid repository names.
+	ErrNameEmpty = errors.New("repository name must have at least one component")
+
+	// ErrNameTooLong is returned when a repository name is longer than
+	// RepositoryNameTotalLengthMax
+	ErrNameTooLong = fmt.Errorf("repository name must not be more than %v characters", NameTotalLengthMax)
+)
+
+// Reference is an opaque object reference identifier that may include
+// modifiers such as a hostname, name, tag, and digest.
 type Reference interface {
-	// Repository returns the repository part of a reference
-	Repository() Repository
-	// String returns the entire reference, including the repository part
+	// String returns the full reference
 	String() string
 }
 
-func parseHostname(s string) (hostname, tail string) {
-	tail = s
-	i := regexp.MustCompile(`^` + RepositoryNameHostnameRegexp.String()).FindStringIndex(s)
-	if i == nil {
-		return
-	}
-	return s[:i[1]], s[i[1]:]
+// Named is an object with a full name
+type Named interface {
+	Name() string
 }
 
-func parseRepositoryName(s string) (repo, tail string) {
-	tail = s
-	i := regexp.MustCompile(`^/(?:` + RepositoryNameComponentRegexp.String() + `/)*` + RepositoryNameComponentRegexp.String()).FindStringIndex(s)
-	if i == nil {
-		return
-	}
-	return s[:i[1]], s[i[1]:]
+// Tagged is an object which has a tag
+type Tagged interface {
+	Tag() string
 }
 
-func parseTag(s string) (tag Tag, tail string) {
-	tail = s
-	if len(s) == 0 || s[0] != ':' {
-		return
-	}
-	tag, err := NewTag(s[1:])
-	if err != nil {
-		return
-	}
-	tail = s[len(tag)+1:]
-	return
+// Digested is an object which has a digest
+// in which it can be referenced by
+type Digested interface {
+	Digest() digest.Digest
 }
 
-func parseDigest(s string) (dgst digest.Digest, tail string) {
-	tail = s
-	if len(s) == 0 || s[0] != '@' {
-		return
+// Canonical reference is an object with a fully unique
+// name including a name with hostname and digest
+type Canonical interface {
+	Reference
+	Named
+	Digested
+}
+
+// SplitHostname splits a named reference into a
+// hostname and name string. If no valid hostname is
+// found, the hostname is empty and the full value
+// is returned as name
+func SplitHostname(named Named) (string, string) {
+	name := named.Name()
+	match := anchoredNameRegexp.FindStringSubmatch(name)
+	if match == nil || len(match) != 3 {
+		return "", name
 	}
-	dgst, err := digest.ParseDigest(s[1:])
-	if err != nil {
-		return
-	}
-	tail = s[len(dgst)+1:]
-	return
+	return match[1], match[2]
 }
 
 // Parse parses s and returns a syntactically valid Reference.
 // If an error was encountered it is returned, along with a nil Reference.
+// NOTE: Parse will not handle short digests.
 func Parse(s string) (Reference, error) {
-	hostname, s := parseHostname(s)
-	name, s := parseRepositoryName(s)
-	repository := Repository{Hostname: hostname, Name: name}
-	if err := repository.Validate(); err != nil {
-		return nil, err
-	}
-	tag, s := parseTag(s)
-	dgst, s := parseDigest(s)
-	if len(s) > 0 {
+	matches := ReferenceRegexp.FindStringSubmatch(s)
+	if matches == nil {
+		if s == "" {
+			return nil, ErrNameEmpty
+		}
+		// TODO(dmcgowan): Provide more specific and helpful error
 		return nil, ErrReferenceInvalidFormat
 	}
 
-	if dgst != "" {
-		return DigestReference{repository: repository, digest: dgst, tag: tag}, nil
+	if len(matches[1]) > NameTotalLengthMax {
+		return nil, ErrNameTooLong
 	}
-	if tag != "" {
-		return TagReference{repository: repository, tag: tag}, nil
+
+	ref := reference{
+		name: matches[1],
+		tag:  matches[2],
 	}
-	return nil, ErrReferenceInvalidFormat
-}
-
-// DigestReference represents a reference of the form `repository@sha256:deadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef`.
-// Implements the Reference interface.
-type DigestReference struct {
-	repository Repository
-	digest     digest.Digest
-	tag        Tag
-}
-
-// Repository returns the repository part.
-func (r DigestReference) Repository() Repository { return r.repository }
-
-// String returns the full string reference.
-func (r DigestReference) String() string {
-	return r.repository.String() + "@" + string(r.digest)
-}
-
-// NewDigestReference returns an initialized DigestReference.
-func NewDigestReference(canonicalRepository string, digest digest.Digest, optionalTag Tag) (DigestReference, error) {
-	ref := DigestReference{}
-
-	repo, err := NewRepository(canonicalRepository)
-	if err != nil {
-		return ref, err
-	}
-	ref.repository = repo
-
-	if err := digest.Validate(); err != nil {
-		return ref, err
-	}
-	ref.digest = digest
-
-	if len(optionalTag) > 0 {
-		if err := optionalTag.Validate(); err != nil {
-			return ref, err
+	if matches[3] != "" {
+		var err error
+		ref.digest, err = digest.ParseDigest(matches[3])
+		if err != nil {
+			return nil, err
 		}
-		ref.tag = optionalTag
 	}
 
-	return ref, err
-}
-
-// TagReference represents a reference of the form `repository:tag`.
-// Implements the Reference interface.
-type TagReference struct {
-	repository Repository
-	tag        Tag
-}
-
-// Repository returns the repository part.
-func (r TagReference) Repository() Repository { return r.repository }
-
-// String returns the full string reference.
-func (r TagReference) String() string {
-	return r.repository.String() + ":" + string(r.tag)
-}
-
-// NewTagReference returns an initialized TagReference.
-func NewTagReference(canonicalRepository string, tagName string) (TagReference, error) {
-	ref := TagReference{}
-
-	repo, err := NewRepository(canonicalRepository)
-	if err != nil {
-		return ref, err
+	r := getBestReferenceType(ref)
+	if r == nil {
+		return nil, ErrNameEmpty
 	}
-	ref.repository = repo
 
-	tag, err := NewTag(tagName)
-	if err != nil {
-		return ref, err
-	}
-	ref.tag = tag
-
-	return ref, err
+	return r, nil
+}
+
+// ParseNamed parses the input string and returns a named
+// object representing the given string. If the input is
+// invalid ErrReferenceInvalidFormat will be returned.
+func ParseNamed(name string) (Named, error) {
+	if !anchoredNameRegexp.MatchString(name) {
+		return nil, ErrReferenceInvalidFormat
+	}
+	return repository(name), nil
+}
+
+func getBestReferenceType(ref reference) Reference {
+	if ref.name == "" {
+		// Allow digest only references
+		if ref.digest != "" {
+			return digestReference(ref.digest)
+		}
+		return nil
+	}
+	if ref.tag == "" {
+		if ref.digest != "" {
+			return canonicalReference{
+				name:   ref.name,
+				digest: ref.digest,
+			}
+		}
+		return repository(ref.name)
+	}
+	if ref.digest == "" {
+		return taggedReference{
+			name: ref.name,
+			tag:  ref.tag,
+		}
+	}
+
+	return ref
+}
+
+type reference struct {
+	name   string
+	tag    string
+	digest digest.Digest
+}
+
+func (r reference) String() string {
+	return r.name + ":" + r.tag + "@" + r.digest.String()
+}
+
+func (r reference) Name() string {
+	return r.name
+}
+
+func (r reference) Tag() string {
+	return r.tag
+}
+
+func (r reference) Digest() digest.Digest {
+	return r.digest
+}
+
+type repository string
+
+func (r repository) String() string {
+	return string(r)
+}
+
+func (r repository) Name() string {
+	return string(r)
+}
+
+type digestReference digest.Digest
+
+func (d digestReference) String() string {
+	return d.String()
+}
+
+func (d digestReference) Digest() digest.Digest {
+	return digest.Digest(d)
+}
+
+type taggedReference struct {
+	name string
+	tag  string
+}
+
+func (t taggedReference) String() string {
+	return t.name + ":" + t.tag
+}
+
+func (t taggedReference) Name() string {
+	return t.name
+}
+
+func (t taggedReference) Tag() string {
+	return t.tag
+}
+
+type canonicalReference struct {
+	name   string
+	digest digest.Digest
+}
+
+func (c canonicalReference) String() string {
+	return c.name + "@" + c.digest.String()
+}
+
+func (c canonicalReference) Name() string {
+	return c.name
+}
+
+func (c canonicalReference) Digest() digest.Digest {
+	return c.digest
 }
diff --git a/reference/reference_test.go b/reference/reference_test.go
index 7af84f33..42d5a34b 100644
--- a/reference/reference_test.go
+++ b/reference/reference_test.go
@@ -1,56 +1,267 @@
 package reference
 
-/*
-var refRegex = regexp.MustCompile(`^([a-z0-9]+(?:[-._][a-z0-9]+)*(?::[0-9]+(?:/[a-z0-9]+(?:[-._][a-z0-9]+)*)+|(?:/[a-z0-9]+(?:[-._][a-z0-9]+)*)+)?)(:[\w][\w.-]{0,127})?(@` + digest.DigestRegexp.String() + `)?$`)
+import (
+	"strconv"
+	"strings"
+	"testing"
 
-func getRepo(s string) string {
-	matches := refRegex.FindStringSubmatch(s)
-	if len(matches) == 0 {
-		return ""
+	"github.com/docker/distribution/digest"
+)
+
+func TestReferenceParse(t *testing.T) {
+	// referenceTestcases is a unified set of testcases for
+	// testing the parsing of references
+	referenceTestcases := []struct {
+		// input is the repository name or name component testcase
+		input string
+		// err is the error expected from Parse, or nil
+		err error
+		// repository is the string representation for the reference
+		repository string
+		// hostname is the hostname expected in the reference
+		hostname string
+		// tag is the tag for the reference
+		tag string
+		// digest is the digest for the reference (enforces digest reference)
+		digest string
+	}{
+		{
+			input:      "test_com",
+			repository: "test_com",
+		},
+		{
+			input:      "test.com:tag",
+			repository: "test.com",
+			tag:        "tag",
+		},
+		{
+			input:      "test.com:5000",
+			repository: "test.com",
+			tag:        "5000",
+		},
+		{
+			input:      "test.com/repo:tag",
+			hostname:   "test.com",
+			repository: "test.com/repo",
+			tag:        "tag",
+		},
+		{
+			input:      "test:5000/repo",
+			hostname:   "test:5000",
+			repository: "test:5000/repo",
+		},
+		{
+			input:      "test:5000/repo:tag",
+			hostname:   "test:5000",
+			repository: "test:5000/repo",
+			tag:        "tag",
+		},
+		{
+			input:      "test:5000/repo@sha256:ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+			hostname:   "test:5000",
+			repository: "test:5000/repo",
+			digest:     "sha256:ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+		},
+		{
+			input:      "test:5000/repo:tag@sha256:ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+			hostname:   "test:5000",
+			repository: "test:5000/repo",
+			tag:        "tag",
+			digest:     "sha256:ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+		},
+		{
+			input:      "test:5000/repo",
+			hostname:   "test:5000",
+			repository: "test:5000/repo",
+		},
+		{
+			input: "",
+			err:   ErrNameEmpty,
+		},
+		{
+			input: ":justtag",
+			err:   ErrReferenceInvalidFormat,
+		},
+		{
+			input: "@sha256:ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+			err:   ErrReferenceInvalidFormat,
+		},
+		{
+			input: "validname@invaliddigest:ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+			err:   digest.ErrDigestUnsupported,
+		},
+		{
+			input: strings.Repeat("a/", 128) + "a:tag",
+			err:   ErrNameTooLong,
+		},
+		{
+			input:      strings.Repeat("a/", 127) + "a:tag-puts-this-over-max",
+			hostname:   "a",
+			repository: strings.Repeat("a/", 127) + "a",
+			tag:        "tag-puts-this-over-max",
+		},
+		{
+			input: "aa/asdf$$^/aa",
+			err:   ErrReferenceInvalidFormat,
+		},
+		{
+			input:      "sub-dom1.foo.com/bar/baz/quux",
+			hostname:   "sub-dom1.foo.com",
+			repository: "sub-dom1.foo.com/bar/baz/quux",
+		},
+		{
+			input:      "sub-dom1.foo.com/bar/baz/quux:some-long-tag",
+			hostname:   "sub-dom1.foo.com",
+			repository: "sub-dom1.foo.com/bar/baz/quux",
+			tag:        "some-long-tag",
+		},
+		{
+			input:      "b.gcr.io/test.example.com/my-app:test.example.com",
+			hostname:   "b.gcr.io",
+			repository: "b.gcr.io/test.example.com/my-app",
+			tag:        "test.example.com",
+		},
+		{
+			input:      "xn--n3h.com/myimage:xn--n3h.com", // ☃.com in punycode
+			hostname:   "xn--n3h.com",
+			repository: "xn--n3h.com/myimage",
+			tag:        "xn--n3h.com",
+		},
+		{
+			input:      "xn--7o8h.com/myimage:xn--7o8h.com@sha512:ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", // 🐳.com in punycode
+			hostname:   "xn--7o8h.com",
+			repository: "xn--7o8h.com/myimage",
+			tag:        "xn--7o8h.com",
+			digest:     "sha512:ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+		},
+		{
+			input:      "foo_bar.com:8080",
+			repository: "foo_bar.com",
+			tag:        "8080",
+		},
+		{
+			input:      "foo/foo_bar.com:8080",
+			hostname:   "foo",
+			repository: "foo/foo_bar.com",
+			tag:        "8080",
+		},
 	}
-	return matches[1]
-}
+	for _, testcase := range referenceTestcases {
+		failf := func(format string, v ...interface{}) {
+			t.Logf(strconv.Quote(testcase.input)+": "+format, v...)
+			t.Fail()
+		}
 
-func testRepository(prefix string) error {
-	for _, s := range []string{
-		prefix + `@sha256:ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff`,
-		prefix + `:frozen@sha256:ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff`,
-		prefix + `:latest`,
-		prefix,
-	} {
-		expected := getRepo(s)
-		ref, err := Parse(s)
-		if err != nil {
-			if expected == "" {
-				continue
+		repo, err := Parse(testcase.input)
+		if testcase.err != nil {
+			if err == nil {
+				failf("missing expected error: %v", testcase.err)
+			} else if testcase.err != err {
+				failf("mismatched error: got %v, expected %v", err, testcase.err)
 			}
-			return err
+			continue
+		} else if err != nil {
+			failf("unexpected parse error: %v", err)
+			continue
 		}
-		if repo := ref.Repository(); repo.String() != expected {
-			return fmt.Errorf("repository string: expected %q, got: %q", expected, repo)
+		if repo.String() != testcase.input {
+			failf("mismatched repo: got %q, expected %q", repo.String(), testcase.input)
+		}
+
+		if named, ok := repo.(Named); ok {
+			if named.Name() != testcase.repository {
+				failf("unexpected repository: got %q, expected %q", named.Name(), testcase.repository)
+			}
+			hostname, _ := SplitHostname(named)
+			if hostname != testcase.hostname {
+				failf("unexpected hostname: got %q, expected %q", hostname, testcase.hostname)
+			}
+		} else if testcase.repository != "" || testcase.hostname != "" {
+			failf("expected named type, got %T", repo)
+		}
+
+		tagged, ok := repo.(Tagged)
+		if testcase.tag != "" {
+			if ok {
+				if tagged.Tag() != testcase.tag {
+					failf("unexpected tag: got %q, expected %q", tagged.Tag(), testcase.tag)
+				}
+			} else {
+				failf("expected tagged type, got %T", repo)
+			}
+		} else if ok {
+			failf("unexpected tagged type")
+		}
+
+		digested, ok := repo.(Digested)
+		if testcase.digest != "" {
+			if ok {
+				if digested.Digest().String() != testcase.digest {
+					failf("unexpected digest: got %q, expected %q", digested.Digest().String(), testcase.digest)
+				}
+			} else {
+				failf("expected digested type, got %T", repo)
+			}
+		} else if ok {
+			failf("unexpected digested type")
 		}
-		if refStr := ref.String(); refStr != s {
-			return fmt.Errorf("reference string: expected %q, got: %q", s, refStr)
-		}
-	}
-	return nil
-}
 
-func TestSimpleRepository(t *testing.T) {
-	if err := testRepository(`busybox`); err != nil {
-		t.Fatal(err)
 	}
 }
 
-func TestUrlRepository(t *testing.T) {
-	if err := testRepository(`docker.io/library/busybox`); err != nil {
-		t.Fatal(err)
+func TestSplitHostname(t *testing.T) {
+	testcases := []struct {
+		input    string
+		hostname string
+		name     string
+	}{
+		{
+			input:    "test.com/foo",
+			hostname: "test.com",
+			name:     "foo",
+		},
+		{
+			input:    "test_com/foo",
+			hostname: "",
+			name:     "test_com/foo",
+		},
+		{
+			input:    "test:8080/foo",
+			hostname: "test:8080",
+			name:     "foo",
+		},
+		{
+			input:    "test.com:8080/foo",
+			hostname: "test.com:8080",
+			name:     "foo",
+		},
+		{
+			input:    "test-com:8080/foo",
+			hostname: "test-com:8080",
+			name:     "foo",
+		},
+		{
+			input:    "xn--n3h.com:18080/foo",
+			hostname: "xn--n3h.com:18080",
+			name:     "foo",
+		},
 	}
-}
+	for _, testcase := range testcases {
+		failf := func(format string, v ...interface{}) {
+			t.Logf(strconv.Quote(testcase.input)+": "+format, v...)
+			t.Fail()
+		}
 
-func TestPort(t *testing.T) {
-	if err := testRepository(`busybox:1234`); err != nil {
-		t.Fatal(err)
+		named, err := ParseNamed(testcase.input)
+		if err != nil {
+			failf("error parsing name: %s", err)
+		}
+		hostname, name := SplitHostname(named)
+		if hostname != testcase.hostname {
+			failf("unexpected hostname: got %q, expected %q", hostname, testcase.hostname)
+		}
+		if name != testcase.name {
+			failf("unexpected name: got %q, expected %q", name, testcase.name)
+		}
 	}
 }
-*/
diff --git a/reference/regexp.go b/reference/regexp.go
new file mode 100644
index 00000000..aa3480c5
--- /dev/null
+++ b/reference/regexp.go
@@ -0,0 +1,37 @@
+package reference
+
+import "regexp"
+
+var (
+	// nameComponentRegexp restricts registry path component names to
+	// start with at least one letter or number, with following parts able to
+	// be separated by one period, dash or underscore.
+	nameComponentRegexp = regexp.MustCompile(`[a-zA-Z0-9]+(?:[._-][a-z0-9]+)*`)
+
+	nameRegexp = regexp.MustCompile(`(?:` + nameComponentRegexp.String() + `/)*` + nameComponentRegexp.String())
+
+	hostnameComponentRegexp = regexp.MustCompile(`(?:[a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9])`)
+
+	// hostnameComponentRegexp restricts the registry hostname component of a repository name to
+	// start with a component as defined by hostnameRegexp and followed by an optional port.
+	hostnameRegexp = regexp.MustCompile(`(?:` + hostnameComponentRegexp.String() + `\.)*` + hostnameComponentRegexp.String() + `(?::[0-9]+)?`)
+
+	// TagRegexp matches valid tag names. From docker/docker:graph/tags.go.
+	TagRegexp = regexp.MustCompile(`[\w][\w.-]{0,127}`)
+
+	// anchoredTagRegexp matches valid tag names, anchored at the start and
+	// end of the matched string.
+	anchoredTagRegexp = regexp.MustCompile(`^` + TagRegexp.String() + `$`)
+
+	// NameRegexp is the format for the name component of references. The
+	// regexp has capturing groups for the hostname and name part omitting
+	// the seperating forward slash from either.
+	NameRegexp = regexp.MustCompile(`(?:` + hostnameRegexp.String() + `/)?` + nameRegexp.String())
+
+	// ReferenceRegexp is the full supported format of a reference. The
+	// regexp has capturing groups for name, tag, and digest components.
+	ReferenceRegexp = regexp.MustCompile(`^((?:` + hostnameRegexp.String() + `/)?` + nameRegexp.String() + `)(?:[:](` + TagRegexp.String() + `))?(?:[@]([A-Za-z][A-Za-z0-9]*(?:[-_+.][A-Za-z][A-Za-z0-9]*)*[:][[:xdigit:]]{32,}))?$`)
+
+	// anchoredNameRegexp is used to parse a name value, capturing hostname
+	anchoredNameRegexp = regexp.MustCompile(`^(?:(` + hostnameRegexp.String() + `)/)?(` + nameRegexp.String() + `)$`)
+)
diff --git a/reference/regexp_test.go b/reference/regexp_test.go
new file mode 100644
index 00000000..9435ee2a
--- /dev/null
+++ b/reference/regexp_test.go
@@ -0,0 +1,398 @@
+package reference
+
+import (
+	"regexp"
+	"strings"
+	"testing"
+)
+
+type regexpMatch struct {
+	input string
+	match bool
+	subs  []string
+}
+
+func checkRegexp(t *testing.T, r *regexp.Regexp, m regexpMatch) {
+	matches := r.FindStringSubmatch(m.input)
+	if m.match && matches != nil {
+		if len(matches) != (r.NumSubexp()+1) || matches[0] != m.input {
+			t.Fatalf("Bad match result: %#v", matches)
+		}
+		if len(matches) < (len(m.subs) + 1) {
+			t.Errorf("Expected %d sub matches, only have %d", len(m.subs), len(matches)-1)
+		}
+		for i := range m.subs {
+			if m.subs[i] != matches[i+1] {
+				t.Errorf("Unexpected submatch %d: %q, expected %q", i+1, matches[i+1], m.subs[i])
+			}
+		}
+	} else if m.match {
+		t.Errorf("Expected match for %q", m.input)
+	} else if matches != nil {
+		t.Errorf("Unexpected match for %q", m.input)
+	}
+}
+
+func TestHostRegexp(t *testing.T) {
+	hostcases := []regexpMatch{
+		{
+			input: "test.com",
+			match: true,
+		},
+		{
+			input: "test.com:10304",
+			match: true,
+		},
+		{
+			input: "test.com:http",
+			match: false,
+		},
+		{
+			input: "localhost",
+			match: true,
+		},
+		{
+			input: "localhost:8080",
+			match: true,
+		},
+		{
+			input: "a",
+			match: true,
+		},
+		{
+			input: "a.b",
+			match: true,
+		},
+		{
+			input: "ab.cd.com",
+			match: true,
+		},
+		{
+			input: "a-b.com",
+			match: true,
+		},
+		{
+			input: "-ab.com",
+			match: false,
+		},
+		{
+			input: "ab-.com",
+			match: false,
+		},
+		{
+			input: "ab.c-om",
+			match: true,
+		},
+		{
+			input: "ab.-com",
+			match: false,
+		},
+		{
+			input: "ab.com-",
+			match: false,
+		},
+		{
+			input: "0101.com",
+			match: true, // TODO(dmcgowan): valid if this should be allowed
+		},
+		{
+			input: "001a.com",
+			match: true,
+		},
+		{
+			input: "b.gbc.io:443",
+			match: true,
+		},
+		{
+			input: "b.gbc.io",
+			match: true,
+		},
+		{
+			input: "xn--n3h.com", // ☃.com in punycode
+			match: true,
+		},
+	}
+	r := regexp.MustCompile(`^` + hostnameRegexp.String() + `$`)
+	for i := range hostcases {
+		checkRegexp(t, r, hostcases[i])
+	}
+}
+
+func TestFullNameRegexp(t *testing.T) {
+	testcases := []regexpMatch{
+		{
+			input: "",
+			match: false,
+		},
+		{
+			input: "short",
+			match: true,
+			subs:  []string{"", "short"},
+		},
+		{
+			input: "simple/name",
+			match: true,
+			subs:  []string{"simple", "name"},
+		},
+		{
+			input: "library/ubuntu",
+			match: true,
+			subs:  []string{"library", "ubuntu"},
+		},
+		{
+			input: "docker/stevvooe/app",
+			match: true,
+			subs:  []string{"docker", "stevvooe/app"},
+		},
+		{
+			input: "aa/aa/aa/aa/aa/aa/aa/aa/aa/bb/bb/bb/bb/bb/bb",
+			match: true,
+			subs:  []string{"aa", "aa/aa/aa/aa/aa/aa/aa/aa/bb/bb/bb/bb/bb/bb"},
+		},
+		{
+			input: "aa/aa/bb/bb/bb",
+			match: true,
+			subs:  []string{"aa", "aa/bb/bb/bb"},
+		},
+		{
+			input: "a/a/a/a",
+			match: true,
+			subs:  []string{"a", "a/a/a"},
+		},
+		{
+			input: "a/a/a/a/",
+			match: false,
+		},
+		{
+			input: "a//a/a",
+			match: false,
+		},
+		{
+			input: "a",
+			match: true,
+			subs:  []string{"", "a"},
+		},
+		{
+			input: "a/aa",
+			match: true,
+			subs:  []string{"a", "aa"},
+		},
+		{
+			input: "a/aa/a",
+			match: true,
+			subs:  []string{"a", "aa/a"},
+		},
+		{
+			input: "foo.com",
+			match: true,
+			subs:  []string{"", "foo.com"},
+		},
+		{
+			input: "foo.com/",
+			match: false,
+		},
+		{
+			input: "foo.com:8080/bar",
+			match: true,
+			subs:  []string{"foo.com:8080", "bar"},
+		},
+		{
+			input: "foo.com:http/bar",
+			match: false,
+		},
+		{
+			input: "foo.com/bar",
+			match: true,
+			subs:  []string{"foo.com", "bar"},
+		},
+		{
+			input: "foo.com/bar/baz",
+			match: true,
+			subs:  []string{"foo.com", "bar/baz"},
+		},
+		{
+			input: "localhost:8080/bar",
+			match: true,
+			subs:  []string{"localhost:8080", "bar"},
+		},
+		{
+			input: "sub-dom1.foo.com/bar/baz/quux",
+			match: true,
+			subs:  []string{"sub-dom1.foo.com", "bar/baz/quux"},
+		},
+		{
+			input: "blog.foo.com/bar/baz",
+			match: true,
+			subs:  []string{"blog.foo.com", "bar/baz"},
+		},
+		{
+			input: "a^a",
+			match: false,
+		},
+		{
+			input: "aa/asdf$$^/aa",
+			match: false,
+		},
+		{
+			input: "asdf$$^/aa",
+			match: false,
+		},
+		{
+			input: "aa-a/a",
+			match: true,
+			subs:  []string{"aa-a", "a"},
+		},
+		{
+			input: strings.Repeat("a/", 128) + "a",
+			match: true,
+			subs:  []string{"a", strings.Repeat("a/", 127) + "a"},
+		},
+		{
+			input: "a-/a/a/a",
+			match: false,
+		},
+		{
+			input: "foo.com/a-/a/a",
+			match: false,
+		},
+		{
+			input: "-foo/bar",
+			match: false,
+		},
+		{
+			input: "foo/bar-",
+			match: false,
+		},
+		{
+			input: "foo-/bar",
+			match: false,
+		},
+		{
+			input: "foo/-bar",
+			match: false,
+		},
+		{
+			input: "_foo/bar",
+			match: false,
+		},
+		{
+			input: "foo_bar",
+			match: true,
+			subs:  []string{"", "foo_bar"},
+		},
+		{
+			input: "foo_bar.com",
+			match: true,
+			subs:  []string{"", "foo_bar.com"},
+		},
+		{
+			input: "foo_bar.com:8080",
+			match: false,
+		},
+		{
+			input: "foo_bar.com:8080/app",
+			match: false,
+		},
+		{
+			input: "foo.com/foo_bar",
+			match: true,
+			subs:  []string{"foo.com", "foo_bar"},
+		},
+		{
+			input: "____/____",
+			match: false,
+		},
+		{
+			input: "_docker/_docker",
+			match: false,
+		},
+		{
+			input: "docker_/docker_",
+			match: false,
+		},
+		{
+			input: "b.gcr.io/test.example.com/my-app",
+			match: true,
+			subs:  []string{"b.gcr.io", "test.example.com/my-app"},
+		},
+		{
+			input: "xn--n3h.com/myimage", // ☃.com in punycode
+			match: true,
+			subs:  []string{"xn--n3h.com", "myimage"},
+		},
+		{
+			input: "xn--7o8h.com/myimage", // 🐳.com in punycode
+			match: true,
+			subs:  []string{"xn--7o8h.com", "myimage"},
+		},
+	}
+	for i := range testcases {
+		checkRegexp(t, anchoredNameRegexp, testcases[i])
+	}
+}
+
+func TestReferenceRegexp(t *testing.T) {
+	testcases := []regexpMatch{
+		{
+			input: "registry.com:8080/myapp:tag",
+			match: true,
+			subs:  []string{"registry.com:8080/myapp", "tag", ""},
+		},
+		{
+			input: "registry.com:8080/myapp@sha256:be178c0543eb17f5f3043021c9e5fcf30285e557a4fc309cce97ff9ca6182912",
+			match: true,
+			subs:  []string{"registry.com:8080/myapp", "", "sha256:be178c0543eb17f5f3043021c9e5fcf30285e557a4fc309cce97ff9ca6182912"},
+		},
+		{
+			input: "registry.com:8080/myapp:tag2@sha256:be178c0543eb17f5f3043021c9e5fcf30285e557a4fc309cce97ff9ca6182912",
+			match: true,
+			subs:  []string{"registry.com:8080/myapp", "tag2", "sha256:be178c0543eb17f5f3043021c9e5fcf30285e557a4fc309cce97ff9ca6182912"},
+		},
+		{
+			input: "registry.com:8080/myapp@sha256:badbadbadbad",
+			match: false,
+		},
+		{
+			input: "registry.com:8080/myapp:invalid~tag",
+			match: false,
+		},
+		{
+			input: "bad_hostname.com:8080/myapp:tag",
+			match: false,
+		},
+		{
+			input:// localhost treated as name, missing tag with 8080 as tag
+			"localhost:8080@sha256:be178c0543eb17f5f3043021c9e5fcf30285e557a4fc309cce97ff9ca6182912",
+			match: true,
+			subs:  []string{"localhost", "8080", "sha256:be178c0543eb17f5f3043021c9e5fcf30285e557a4fc309cce97ff9ca6182912"},
+		},
+		{
+			input: "localhost:8080/name@sha256:be178c0543eb17f5f3043021c9e5fcf30285e557a4fc309cce97ff9ca6182912",
+			match: true,
+			subs:  []string{"localhost:8080/name", "", "sha256:be178c0543eb17f5f3043021c9e5fcf30285e557a4fc309cce97ff9ca6182912"},
+		},
+		{
+			input: "localhost:http/name@sha256:be178c0543eb17f5f3043021c9e5fcf30285e557a4fc309cce97ff9ca6182912",
+			match: false,
+		},
+		{
+			// localhost will be treated as an image name without a host
+			input: "localhost@sha256:be178c0543eb17f5f3043021c9e5fcf30285e557a4fc309cce97ff9ca6182912",
+			match: true,
+			subs:  []string{"localhost", "", "sha256:be178c0543eb17f5f3043021c9e5fcf30285e557a4fc309cce97ff9ca6182912"},
+		},
+		{
+			input: "registry.com:8080/myapp@bad",
+			match: false,
+		},
+		{
+			input: "registry.com:8080/myapp@2bad",
+			match: false, // TODO(dmcgowan): Support this as valid
+		},
+	}
+
+	for i := range testcases {
+		checkRegexp(t, ReferenceRegexp, testcases[i])
+	}
+
+}
diff --git a/reference/repository.go b/reference/repository.go
deleted file mode 100644
index 936b0929..00000000
--- a/reference/repository.go
+++ /dev/null
@@ -1,136 +0,0 @@
-package reference
-
-import (
-	"errors"
-	"fmt"
-	"regexp"
-	"strings"
-)
-
-const (
-	// RepositoryNameTotalLengthMax is the maximum total number of characters in a repository name.
-	RepositoryNameTotalLengthMax = 255
-)
-
-// RepositoryNameComponentRegexp restricts registry path component names to
-// start with at least one letter or number, with following parts able to
-// be separated by one period, dash or underscore.
-var RepositoryNameComponentRegexp = regexp.MustCompile(`[a-zA-Z0-9]+(?:[._-][a-z0-9]+)*`)
-
-// RepositoryNameComponentAnchoredRegexp is the version of
-// RepositoryNameComponentRegexp which must completely match the content
-var RepositoryNameComponentAnchoredRegexp = regexp.MustCompile(`^` + RepositoryNameComponentRegexp.String() + `$`)
-
-// RepositoryNameHostnameRegexp restricts the registry hostname component of a repository name to
-// start with a component as defined by RepositoryNameComponentRegexp and followed by an optional port.
-var RepositoryNameHostnameRegexp = regexp.MustCompile(RepositoryNameComponentRegexp.String() + `(?::[0-9]+)?`)
-
-// RepositoryNameHostnameAnchoredRegexp is the version of
-// RepositoryNameHostnameRegexp which must completely match the content.
-var RepositoryNameHostnameAnchoredRegexp = regexp.MustCompile(`^` + RepositoryNameHostnameRegexp.String() + `$`)
-
-// RepositoryNameRegexp builds on RepositoryNameComponentRegexp to allow
-// multiple path components, separated by a forward slash.
-var RepositoryNameRegexp = regexp.MustCompile(`(?:` + RepositoryNameHostnameRegexp.String() + `/)?(?:` + RepositoryNameComponentRegexp.String() + `/)*` + RepositoryNameComponentRegexp.String())
-
-var (
-	// ErrRepositoryNameEmpty is returned for empty, invalid repository names.
-	ErrRepositoryNameEmpty = errors.New("repository name must have at least one component")
-
-	// ErrRepositoryNameMissingHostname is returned when a repository name
-	// does not start with a hostname
-	ErrRepositoryNameMissingHostname = errors.New("repository name must start with a hostname")
-
-	// ErrRepositoryNameHostnameInvalid is returned when a repository name
-	// does not match RepositoryNameHostnameRegexp
-	ErrRepositoryNameHostnameInvalid = fmt.Errorf("repository name must match %q", RepositoryNameHostnameRegexp.String())
-
-	// ErrRepositoryNameLong is returned when a repository name is longer than
-	// RepositoryNameTotalLengthMax
-	ErrRepositoryNameLong = fmt.Errorf("repository name must not be more than %v characters", RepositoryNameTotalLengthMax)
-
-	// ErrRepositoryNameComponentInvalid is returned when a repository name does
-	// not match RepositoryNameComponentRegexp
-	ErrRepositoryNameComponentInvalid = fmt.Errorf("repository name component must match %q", RepositoryNameComponentRegexp.String())
-)
-
-// Repository represents a reference to a Repository.
-type Repository struct {
-	// Hostname refers to the registry hostname where the repository resides.
-	Hostname string
-	// Name is a slash (`/`) separated list of string components.
-	Name string
-}
-
-// String returns the string representation of a repository.
-func (r Repository) String() string {
-	// Hostname is not supposed to be empty, but let's be nice.
-	if len(r.Hostname) == 0 {
-		return r.Name
-	}
-	return r.Hostname + "/" + r.Name
-}
-
-// Validate ensures the repository name is valid for use in the
-// registry. This function accepts a superset of what might be accepted by
-// docker core or docker hub. If the name does not pass validation, an error,
-// describing the conditions, is returned.
-//
-// Effectively, the name should comply with the following grammar:
-//
-//	repository			:= hostname ['/' component]+
-//	hostname 			:= component [':' port-number]
-//	component			:= alpha-numeric [separator alpha-numeric]*
-// 	alpha-numeric			:= /[a-zA-Z0-9]+/
-//	separator			:= /[._-]/
-//	port-number			:= /[0-9]+/
-//
-// The result of the production should be limited to 255 characters.
-func (r Repository) Validate() error {
-	n := len(r.String())
-	switch {
-	case n == 0:
-		return ErrRepositoryNameEmpty
-	case n > RepositoryNameTotalLengthMax:
-		return ErrRepositoryNameLong
-	case len(r.Hostname) <= 0:
-		return ErrRepositoryNameMissingHostname
-	case !RepositoryNameHostnameAnchoredRegexp.MatchString(r.Hostname):
-		return ErrRepositoryNameHostnameInvalid
-	}
-
-	components := r.Name
-	for {
-		var component string
-		sep := strings.Index(components, "/")
-		if sep >= 0 {
-			component = components[:sep]
-			components = components[sep+1:]
-		} else { // if no more slashes
-			component = components
-			components = ""
-		}
-		if !RepositoryNameComponentAnchoredRegexp.MatchString(component) {
-			return ErrRepositoryNameComponentInvalid
-		}
-		if sep < 0 {
-			return nil
-		}
-	}
-}
-
-// NewRepository returns a valid Repository from an input string representing
-// the canonical form of a repository name.
-// If the validation fails, an error is returned.
-func NewRepository(canonicalName string) (repo Repository, err error) {
-	if len(canonicalName) == 0 {
-		return repo, ErrRepositoryNameEmpty
-	}
-	i := strings.Index(canonicalName, "/")
-	if i <= 0 {
-		return repo, ErrRepositoryNameMissingHostname
-	}
-	repo.Hostname = canonicalName[:i]
-	repo.Name = canonicalName[i+1:]
-	return repo, repo.Validate()
-}
diff --git a/reference/repository_test.go b/reference/repository_test.go
deleted file mode 100644
index 67d65f9d..00000000
--- a/reference/repository_test.go
+++ /dev/null
@@ -1,286 +0,0 @@
-package reference
-
-import (
-	"regexp"
-	"strconv"
-	"strings"
-	"testing"
-)
-
-var (
-	// regexpTestcases is a unified set of testcases for
-	// TestValidateRepositoryName and TestRepositoryNameRegexp.
-	// Some of them are valid inputs for one and not the other.
-	regexpTestcases = []struct {
-		// input is the repository name or name component testcase
-		input string
-		// err is the error expected from ValidateRepositoryName, or nil
-		err error
-		// invalid should be true if the testcase is *not* expected to
-		// match RepositoryNameRegexp
-		invalid bool
-	}{
-		{
-			input:   "",
-			err:     ErrRepositoryNameEmpty,
-			invalid: true,
-		},
-		{
-			input: "short",
-			err:   ErrRepositoryNameMissingHostname,
-		},
-		{
-			input: "simple/name",
-		},
-		{
-			input: "library/ubuntu",
-		},
-		{
-			input: "docker/stevvooe/app",
-		},
-		{
-			input: "aa/aa/aa/aa/aa/aa/aa/aa/aa/bb/bb/bb/bb/bb/bb",
-		},
-		{
-			input: "aa/aa/bb/bb/bb",
-		},
-		{
-			input: "a/a/a/b/b",
-		},
-		{
-			input:   "a/a/a/a/",
-			err:     ErrRepositoryNameComponentInvalid,
-			invalid: true,
-		},
-		{
-			input:   "a//a/a",
-			err:     ErrRepositoryNameComponentInvalid,
-			invalid: true,
-		},
-		{
-			input: "a",
-			err:   ErrRepositoryNameMissingHostname,
-		},
-		{
-			input: "a/aa",
-		},
-		{
-			input: "aa/a",
-		},
-		{
-			input: "a/aa/a",
-		},
-		{
-			input:   "foo.com/",
-			err:     ErrRepositoryNameComponentInvalid,
-			invalid: true,
-		},
-		{
-			input: "foo.com:8080/bar",
-		},
-		{
-			input: "foo.com/bar",
-		},
-		{
-			input: "foo.com/bar/baz",
-		},
-		{
-			input: "foo.com/bar/baz/quux",
-		},
-		{
-			input: "blog.foo.com/bar/baz",
-		},
-		{
-			input: "asdf",
-			err:   ErrRepositoryNameMissingHostname,
-		},
-		{
-			input:   "aa/asdf$$^/aa",
-			err:     ErrRepositoryNameComponentInvalid,
-			invalid: true,
-		},
-		{
-			input:   "asdf$$^/aa",
-			err:     ErrRepositoryNameHostnameInvalid,
-			invalid: true,
-		},
-		{
-			input: "aa-a/aa",
-		},
-		{
-			input: "aa/aa",
-		},
-		{
-			input: "a-a/a-a",
-		},
-		{
-			input: "a",
-			err:   ErrRepositoryNameMissingHostname,
-		},
-		{
-			input: "a/image",
-		},
-		{
-			input:   "a-/a/a/a",
-			err:     ErrRepositoryNameHostnameInvalid,
-			invalid: true,
-		},
-		{
-			input:   "a/a-/a/a/a",
-			err:     ErrRepositoryNameComponentInvalid,
-			invalid: true,
-		},
-		{
-			// total length = 255
-			input: "a/" + strings.Repeat("a", 253),
-		},
-		{
-			// total length = 256
-			input: "b/" + strings.Repeat("a", 254),
-			err:   ErrRepositoryNameLong,
-		},
-		{
-			input:   "-foo/bar",
-			err:     ErrRepositoryNameHostnameInvalid,
-			invalid: true,
-		},
-		{
-			input:   "foo/bar-",
-			err:     ErrRepositoryNameComponentInvalid,
-			invalid: true,
-		},
-		{
-			input:   "foo-/bar",
-			err:     ErrRepositoryNameHostnameInvalid,
-			invalid: true,
-		},
-		{
-			input:   "foo/-bar",
-			err:     ErrRepositoryNameComponentInvalid,
-			invalid: true,
-		},
-		{
-			input:   "_foo/bar",
-			err:     ErrRepositoryNameHostnameInvalid,
-			invalid: true,
-		},
-		{
-			input:   "foo/bar_",
-			err:     ErrRepositoryNameComponentInvalid,
-			invalid: true,
-		},
-		{
-			input:   "____/____",
-			err:     ErrRepositoryNameHostnameInvalid,
-			invalid: true,
-		},
-		{
-			input:   "_docker/_docker",
-			err:     ErrRepositoryNameHostnameInvalid,
-			invalid: true,
-		},
-		{
-			input:   "docker_/docker_",
-			err:     ErrRepositoryNameHostnameInvalid,
-			invalid: true,
-		},
-		{
-			input:   "do__cker/docker",
-			err:     ErrRepositoryNameComponentInvalid,
-			invalid: true,
-		},
-		{
-			input:   "docker./docker",
-			err:     ErrRepositoryNameComponentInvalid,
-			invalid: true,
-		},
-		{
-			input:   ".docker/docker",
-			err:     ErrRepositoryNameComponentInvalid,
-			invalid: true,
-		},
-		{
-			input:   "do..cker/docker",
-			err:     ErrRepositoryNameComponentInvalid,
-			invalid: true,
-		},
-		{
-			input:   "docker-/docker",
-			err:     ErrRepositoryNameComponentInvalid,
-			invalid: true,
-		},
-		{
-			input: "-docker/docker",
-			err:   ErrRepositoryNameComponentInvalid,
-		},
-		{
-			input:   "xn--n3h.com/myimage", // http://☃.com in punycode
-			err:     ErrRepositoryNameHostnameInvalid,
-			invalid: true,
-		},
-		{
-			input:   "xn--7o8h.com/myimage", // http://🐳.com in punycode
-			err:     ErrRepositoryNameHostnameInvalid,
-			invalid: true,
-		},
-		{
-			input: "b.gcr.io/test.example.com/my-app", // embedded domain component
-		},
-		{
-			input: "xn--n3h.com/myimage", // http://☃.com in punycode
-		},
-		{
-			input: "xn--7o8h.com/myimage", // http://🐳.com in punycode
-		},
-		{
-			input: "registry.io/foo/project--id.module--name.ver---sion--name", // image with hostname
-		},
-	}
-)
-
-// TestValidateRepositoryName tests the ValidateRepositoryName function,
-// which uses RepositoryNameComponentAnchoredRegexp for validation
-func TestValidateRepositoryName(t *testing.T) {
-	for _, testcase := range regexpTestcases {
-		failf := func(format string, v ...interface{}) {
-			t.Logf(strconv.Quote(testcase.input)+": "+format, v...)
-			t.Fail()
-		}
-
-		if _, err := NewRepository(testcase.input); err != testcase.err {
-			if testcase.err != nil {
-				if err != nil {
-					failf("unexpected error for invalid repository: got %v, expected %v", err, testcase.err)
-				} else {
-					failf("expected invalid repository: %v", testcase.err)
-				}
-			} else {
-				if err != nil {
-					// Wrong error returned.
-					failf("unexpected error validating repository name: %v, expected %v", err, testcase.err)
-				} else {
-					failf("unexpected error validating repository name: %v", err)
-				}
-			}
-		}
-	}
-}
-
-func TestRepositoryNameRegexp(t *testing.T) {
-	AnchoredRepositoryNameRegexp := regexp.MustCompile(`^` + RepositoryNameRegexp.String() + `$`)
-	for _, testcase := range regexpTestcases {
-		failf := func(format string, v ...interface{}) {
-			t.Logf(strconv.Quote(testcase.input)+": "+format, v...)
-			t.Fail()
-		}
-
-		matches := AnchoredRepositoryNameRegexp.MatchString(testcase.input)
-		if matches == testcase.invalid {
-			if testcase.invalid {
-				failf("expected invalid repository name %s", testcase.input)
-			} else {
-				failf("expected valid repository name %s", testcase.input)
-			}
-		}
-	}
-}
diff --git a/reference/tag.go b/reference/tag.go
deleted file mode 100644
index 8deee36e..00000000
--- a/reference/tag.go
+++ /dev/null
@@ -1,38 +0,0 @@
-package reference
-
-import (
-	"fmt"
-	"regexp"
-)
-
-var (
-	// TagRegexp matches valid tag names. From docker/docker:graph/tags.go.
-	TagRegexp = regexp.MustCompile(`[\w][\w.-]{0,127}`)
-
-	// TagAnchoredRegexp matches valid tag names, anchored at the start and
-	// end of the matched string.
-	TagAnchoredRegexp = regexp.MustCompile(`^` + TagRegexp.String() + `$`)
-
-	// ErrTagInvalid is returned when a tag does not match TagAnchoredRegexp.
-	ErrTagInvalid = fmt.Errorf("tag name must match %q", TagRegexp.String())
-)
-
-// Tag represents an image's tag name.
-type Tag string
-
-// NewTag returns a valid Tag from an input string s.
-// If the validation fails, an error is returned.
-func NewTag(s string) (Tag, error) {
-	tag := Tag(s)
-	return tag, tag.Validate()
-}
-
-// Validate returns ErrTagInvalid if tag does not match TagAnchoredRegexp.
-//
-//	tag	:= [\w][\w.-]{0,127}
-func (tag Tag) Validate() error {
-	if !TagAnchoredRegexp.MatchString(string(tag)) {
-		return ErrTagInvalid
-	}
-	return nil
-}
diff --git a/registry/api/v2/descriptors.go b/registry/api/v2/descriptors.go
index ef37997a..9cfb2fb5 100644
--- a/registry/api/v2/descriptors.go
+++ b/registry/api/v2/descriptors.go
@@ -13,7 +13,7 @@ var (
 	nameParameterDescriptor = ParameterDescriptor{
 		Name:        "name",
 		Type:        "string",
-		Format:      reference.RepositoryNameRegexp.String(),
+		Format:      reference.NameRegexp.String(),
 		Required:    true,
 		Description: `Name of the target repository.`,
 	}
@@ -390,7 +390,7 @@ var routeDescriptors = []RouteDescriptor{
 	},
 	{
 		Name:        RouteNameTags,
-		Path:        "/v2/{name:" + reference.RepositoryNameRegexp.String() + "}/tags/list",
+		Path:        "/v2/{name:" + reference.NameRegexp.String() + "}/tags/list",
 		Entity:      "Tags",
 		Description: "Retrieve information about tags.",
 		Methods: []MethodDescriptor{
@@ -518,7 +518,7 @@ var routeDescriptors = []RouteDescriptor{
 	},
 	{
 		Name:        RouteNameManifest,
-		Path:        "/v2/{name:" + reference.RepositoryNameRegexp.String() + "}/manifests/{reference:" + reference.TagRegexp.String() + "|" + digest.DigestRegexp.String() + "}",
+		Path:        "/v2/{name:" + reference.NameRegexp.String() + "}/manifests/{reference:" + reference.TagRegexp.String() + "|" + digest.DigestRegexp.String() + "}",
 		Entity:      "Manifest",
 		Description: "Create, update, delete and retrieve manifests.",
 		Methods: []MethodDescriptor{
@@ -783,7 +783,7 @@ var routeDescriptors = []RouteDescriptor{
 
 	{
 		Name:        RouteNameBlob,
-		Path:        "/v2/{name:" + reference.RepositoryNameRegexp.String() + "}/blobs/{digest:" + digest.DigestRegexp.String() + "}",
+		Path:        "/v2/{name:" + reference.NameRegexp.String() + "}/blobs/{digest:" + digest.DigestRegexp.String() + "}",
 		Entity:      "Blob",
 		Description: "Operations on blobs identified by `name` and `digest`. Used to fetch or delete layers by digest.",
 		Methods: []MethodDescriptor{
@@ -1007,7 +1007,7 @@ var routeDescriptors = []RouteDescriptor{
 
 	{
 		Name:        RouteNameBlobUpload,
-		Path:        "/v2/{name:" + reference.RepositoryNameRegexp.String() + "}/blobs/uploads/",
+		Path:        "/v2/{name:" + reference.NameRegexp.String() + "}/blobs/uploads/",
 		Entity:      "Initiate Blob Upload",
 		Description: "Initiate a blob upload. This endpoint can be used to create resumable uploads or monolithic uploads.",
 		Methods: []MethodDescriptor{
@@ -1129,7 +1129,7 @@ var routeDescriptors = []RouteDescriptor{
 
 	{
 		Name:        RouteNameBlobUploadChunk,
-		Path:        "/v2/{name:" + reference.RepositoryNameRegexp.String() + "}/blobs/uploads/{uuid:[a-zA-Z0-9-_.=]+}",
+		Path:        "/v2/{name:" + reference.NameRegexp.String() + "}/blobs/uploads/{uuid:[a-zA-Z0-9-_.=]+}",
 		Entity:      "Blob Upload",
 		Description: "Interact with blob uploads. Clients should never assemble URLs for this endpoint and should only take it through the `Location` header on related API requests. The `Location` header and its parameters should be preserved by clients, using the latest value returned via upload related API calls.",
 		Methods: []MethodDescriptor{
diff --git a/registry/api/v2/routes_test.go b/registry/api/v2/routes_test.go
index b8d724df..f6379977 100644
--- a/registry/api/v2/routes_test.go
+++ b/registry/api/v2/routes_test.go
@@ -170,6 +170,14 @@ func TestRouter(t *testing.T) {
 				"name": "foo/bar/manifests",
 			},
 		},
+		{
+			RouteName:  RouteNameManifest,
+			RequestURI: "/v2/locahost:8080/foo/bar/baz/manifests/tag",
+			Vars: map[string]string{
+				"name":      "locahost:8080/foo/bar/baz",
+				"reference": "tag",
+			},
+		},
 	}
 
 	checkTestRouter(t, testCases, "", true)
diff --git a/registry/client/repository.go b/registry/client/repository.go
index db45a464..fc709ded 100644
--- a/registry/client/repository.go
+++ b/registry/client/repository.go
@@ -97,9 +97,9 @@ func (r *registry) Repositories(ctx context.Context, entries []string, last stri
 	return numFilled, returnErr
 }
 
-// NewRepository creates a new Repository for the given canonical repository name and base URL.
-func NewRepository(ctx context.Context, canonicalName, baseURL string, transport http.RoundTripper) (distribution.Repository, error) {
-	if _, err := reference.NewRepository(canonicalName); err != nil {
+// NewRepository creates a new Repository for the given repository name and base URL.
+func NewRepository(ctx context.Context, name, baseURL string, transport http.RoundTripper) (distribution.Repository, error) {
+	if _, err := reference.ParseNamed(name); err != nil {
 		return nil, err
 	}
 
@@ -116,7 +116,7 @@ func NewRepository(ctx context.Context, canonicalName, baseURL string, transport
 	return &repository{
 		client:  client,
 		ub:      ub,
-		name:    canonicalName,
+		name:    name,
 		context: ctx,
 	}, nil
 }
diff --git a/registry/storage/cache/memory/memory.go b/registry/storage/cache/memory/memory.go
index 725a68e7..68a68f08 100644
--- a/registry/storage/cache/memory/memory.go
+++ b/registry/storage/cache/memory/memory.go
@@ -25,8 +25,8 @@ func NewInMemoryBlobDescriptorCacheProvider() cache.BlobDescriptorCacheProvider
 	}
 }
 
-func (imbdcp *inMemoryBlobDescriptorCacheProvider) RepositoryScoped(canonicalName string) (distribution.BlobDescriptorService, error) {
-	if _, err := reference.NewRepository(canonicalName); err != nil {
+func (imbdcp *inMemoryBlobDescriptorCacheProvider) RepositoryScoped(repo string) (distribution.BlobDescriptorService, error) {
+	if _, err := reference.ParseNamed(repo); err != nil {
 		return nil, err
 	}
 
@@ -34,9 +34,9 @@ func (imbdcp *inMemoryBlobDescriptorCacheProvider) RepositoryScoped(canonicalNam
 	defer imbdcp.mu.RUnlock()
 
 	return &repositoryScopedInMemoryBlobDescriptorCache{
-		repo:       canonicalName,
+		repo:       repo,
 		parent:     imbdcp,
-		repository: imbdcp.repositories[canonicalName],
+		repository: imbdcp.repositories[repo],
 	}, nil
 }
 
diff --git a/registry/storage/cache/redis/redis.go b/registry/storage/cache/redis/redis.go
index 54138f3d..1736756e 100644
--- a/registry/storage/cache/redis/redis.go
+++ b/registry/storage/cache/redis/redis.go
@@ -40,13 +40,13 @@ func NewRedisBlobDescriptorCacheProvider(pool *redis.Pool) cache.BlobDescriptorC
 }
 
 // RepositoryScoped returns the scoped cache.
-func (rbds *redisBlobDescriptorService) RepositoryScoped(canonicalName string) (distribution.BlobDescriptorService, error) {
-	if _, err := reference.NewRepository(canonicalName); err != nil {
+func (rbds *redisBlobDescriptorService) RepositoryScoped(repo string) (distribution.BlobDescriptorService, error) {
+	if _, err := reference.ParseNamed(repo); err != nil {
 		return nil, err
 	}
 
 	return &repositoryScopedRedisBlobDescriptorService{
-		repo:     canonicalName,
+		repo:     repo,
 		upstream: rbds,
 	}, nil
 }
diff --git a/registry/storage/registry.go b/registry/storage/registry.go
index e3b132c5..1050920a 100644
--- a/registry/storage/registry.go
+++ b/registry/storage/registry.go
@@ -108,7 +108,7 @@ func (reg *registry) Scope() distribution.Scope {
 // Instances should not be shared between goroutines but are cheap to
 // allocate. In general, they should be request scoped.
 func (reg *registry) Repository(ctx context.Context, canonicalName string) (distribution.Repository, error) {
-	if _, err := reference.NewRepository(canonicalName); err != nil {
+	if _, err := reference.ParseNamed(canonicalName); err != nil {
 		return nil, distribution.ErrRepositoryNameInvalid{
 			Name:   canonicalName,
 			Reason: err,