diff --git a/common/names.go b/common/names.go
new file mode 100644
index 000000000..ce25e4872
--- /dev/null
+++ b/common/names.go
@@ -0,0 +1,19 @@
+package common
+
+import (
+	"regexp"
+)
+
+// RepositoryNameComponentRegexp restricts registtry path components names to
+// start with at least two letters or numbers, with following parts able to
+// separated by one period, dash or underscore.
+var RepositoryNameComponentRegexp = regexp.MustCompile(`[a-z0-9](?:[a-z0-9]+[._-]?)*[a-z0-9]`)
+
+// RepositoryNameRegexp builds on RepositoryNameComponentRegexp to allow 2 to
+// 5 path components, separated by a forward slash.
+var RepositoryNameRegexp = regexp.MustCompile(`(?:` + RepositoryNameComponentRegexp.String() + `/){1,4}` + RepositoryNameComponentRegexp.String())
+
+// TagNameRegexp matches valid tag names. From docker/docker:graph/tags.go.
+var TagNameRegexp = regexp.MustCompile(`[\w][\w.-]{0,127}`)
+
+// TODO(stevvooe): Contribute these exports back to core, so they are shared.
diff --git a/common/names_test.go b/common/names_test.go
new file mode 100644
index 000000000..17655984f
--- /dev/null
+++ b/common/names_test.go
@@ -0,0 +1,62 @@
+package common
+
+import (
+	"testing"
+)
+
+func TestRepositoryNameRegexp(t *testing.T) {
+	for _, testcase := range []struct {
+		input string
+		valid bool
+	}{
+		{
+			input: "simple/name",
+			valid: true,
+		},
+		{
+			input: "library/ubuntu",
+			valid: true,
+		},
+		{
+			input: "docker/stevvooe/app",
+			valid: true,
+		},
+		{
+			input: "aa/aa/aa/aa/aa/aa/aa/aa/aa/bb/bb/bb/bb/bb/bb",
+			valid: true,
+		},
+		{
+			input: "a/a/a/a/a/a/b/b/b/b",
+			valid: false,
+		},
+		{
+			input: "a/a/a/a/",
+			valid: false,
+		},
+		{
+			input: "foo.com/bar/baz",
+			valid: true,
+		},
+		{
+			input: "blog.foo.com/bar/baz",
+			valid: true,
+		},
+		{
+			input: "asdf",
+			valid: false,
+		},
+		{
+			input: "asdf$$^/",
+			valid: false,
+		},
+	} {
+		if RepositoryNameRegexp.MatchString(testcase.input) != testcase.valid {
+			status := "invalid"
+			if testcase.valid {
+				status = "valid"
+			}
+
+			t.Fatalf("expected %q to be %s repository name", testcase.input, status)
+		}
+	}
+}
diff --git a/common/tarsum.go b/common/tarsum.go
new file mode 100644
index 000000000..5a6e7d215
--- /dev/null
+++ b/common/tarsum.go
@@ -0,0 +1,70 @@
+package common
+
+import (
+	"fmt"
+
+	"regexp"
+)
+
+// TarSumRegexp defines a reguler expression to match tarsum identifiers.
+var TarsumRegexp = regexp.MustCompile("tarsum(?:.[a-z0-9]+)?\\+[a-zA-Z0-9]+:[A-Fa-f0-9]+")
+
+// TarsumRegexpCapturing defines a reguler expression to match tarsum identifiers with
+// capture groups corresponding to each component.
+var TarsumRegexpCapturing = regexp.MustCompile("(tarsum)(.([a-z0-9]+))?\\+([a-zA-Z0-9]+):([A-Fa-f0-9]+)")
+
+// TarSumInfo contains information about a parsed tarsum.
+type TarSumInfo struct {
+	// Version contains the version of the tarsum.
+	Version string
+
+	// Algorithm contains the algorithm for the final digest
+	Algorithm string
+
+	// Digest contains the hex-encoded digest.
+	Digest string
+}
+
+type InvalidTarSumError struct {
+	TarSum string
+}
+
+func (e InvalidTarSumError) Error() string {
+	return fmt.Sprintf("invalid tarsum: %q", e.TarSum)
+}
+
+// ParseTarSum parses a tarsum string into its components of interest. For
+// example, this method may receive the tarsum in the following format:
+//
+//		tarsum.v1+sha256:220a60ecd4a3c32c282622a625a54db9ba0ff55b5ba9c29c7064a2bc358b6a3e
+//
+// The function will return the following:
+//
+//		TarSumInfo{
+//			Version: "v1",
+//			Algorithm: "sha256",
+//			Digest: "220a60ecd4a3c32c282622a625a54db9ba0ff55b5ba9c29c7064a2bc358b6a3e",
+//		}
+//
+func ParseTarSum(tarSum string) (tsi TarSumInfo, err error) {
+	components := TarsumRegexpCapturing.FindStringSubmatch(tarSum)
+
+	if len(components) != 1+TarsumRegexpCapturing.NumSubexp() {
+		return TarSumInfo{}, InvalidTarSumError{TarSum: tarSum}
+	}
+
+	return TarSumInfo{
+		Version:   components[3],
+		Algorithm: components[4],
+		Digest:    components[5],
+	}, nil
+}
+
+// String returns the valid, string representation of the tarsum info.
+func (tsi TarSumInfo) String() string {
+	if tsi.Version == "" {
+		return fmt.Sprintf("tarsum+%s:%s", tsi.Algorithm, tsi.Digest)
+	}
+
+	return fmt.Sprintf("tarsum.%s+%s:%s", tsi.Version, tsi.Algorithm, tsi.Digest)
+}
diff --git a/common/tarsum_test.go b/common/tarsum_test.go
new file mode 100644
index 000000000..e860c9cdf
--- /dev/null
+++ b/common/tarsum_test.go
@@ -0,0 +1,79 @@
+package common
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestParseTarSumComponents(t *testing.T) {
+	for _, testcase := range []struct {
+		input    string
+		expected TarSumInfo
+		err      error
+	}{
+		{
+			input: "tarsum.v1+sha256:220a60ecd4a3c32c282622a625a54db9ba0ff55b5ba9c29c7064a2bc358b6a3e",
+			expected: TarSumInfo{
+				Version:   "v1",
+				Algorithm: "sha256",
+				Digest:    "220a60ecd4a3c32c282622a625a54db9ba0ff55b5ba9c29c7064a2bc358b6a3e",
+			},
+		},
+		{
+			input: "",
+			err:   InvalidTarSumError{},
+		},
+		{
+			input: "purejunk",
+			err:   InvalidTarSumError{TarSum: "purejunk"},
+		},
+		{
+			input: "tarsum.v23+test:12341234123412341effefefe",
+			expected: TarSumInfo{
+				Version:   "v23",
+				Algorithm: "test",
+				Digest:    "12341234123412341effefefe",
+			},
+		},
+
+		// The following test cases are ported from docker core
+		{
+			// Version 0 tarsum
+			input: "tarsum+sha256:e58fcf7418d4390dec8e8fb69d88c06ec07039d651fedd3aa72af9972e7d046b",
+			expected: TarSumInfo{
+				Algorithm: "sha256",
+				Digest:    "e58fcf7418d4390dec8e8fb69d88c06ec07039d651fedd3aa72af9972e7d046b",
+			},
+		},
+		{
+			// Dev version tarsum
+			input: "tarsum.dev+sha256:e58fcf7418d4390dec8e8fb69d88c06ec07039d651fedd3aa72af9972e7d046b",
+			expected: TarSumInfo{
+				Version:   "dev",
+				Algorithm: "sha256",
+				Digest:    "e58fcf7418d4390dec8e8fb69d88c06ec07039d651fedd3aa72af9972e7d046b",
+			},
+		},
+	} {
+		tsi, err := ParseTarSum(testcase.input)
+		if err != nil {
+			if testcase.err != nil && err == testcase.err {
+				continue // passes
+			}
+
+			t.Fatalf("unexpected error parsing tarsum: %v", err)
+		}
+
+		if testcase.err != nil {
+			t.Fatalf("expected error not encountered on %q: %v", testcase.input, testcase.err)
+		}
+
+		if !reflect.DeepEqual(tsi, testcase.expected) {
+			t.Fatalf("expected tarsum info: %v != %v", tsi, testcase.expected)
+		}
+
+		if testcase.input != tsi.String() {
+			t.Fatalf("input should equal output: %q != %q", tsi.String(), testcase.input)
+		}
+	}
+}