diff --git a/glide.lock b/glide.lock
index a94dad3..3994d7a 100644
--- a/glide.lock
+++ b/glide.lock
@@ -1,5 +1,5 @@
-hash: 9b4441d8a5beafc0334e55c3c0c98e32b60d51d7b0ceba8110b61b26f2b498fa
-updated: 2017-02-06T10:48:09.882426248+08:00
+hash: 96d33c78edbe7fe735d07563db6d34f7493db27e52984ada2ff5aaa2ea434979
+updated: 2017-02-06T21:22:16.913065811-08:00
 imports:
 - name: github.com/inconshreveable/mousetrap
   version: 76626ae9c91c4f2a10f34cad8ce83ea42c93bb75
diff --git a/glide.yaml b/glide.yaml
index a6c6944..379f28d 100644
--- a/glide.yaml
+++ b/glide.yaml
@@ -1,5 +1,7 @@
 package: github.com/opencontainers/image-tools
 import:
+- package: github.com/opencontainers/go-digest
+  version: v1.0.0-rc0
 - package: github.com/opencontainers/image-spec
   version: v1.0.0-rc4
   subpackages:
diff --git a/image/descriptor.go b/image/descriptor.go
index 75fd390..f19642c 100644
--- a/image/descriptor.go
+++ b/image/descriptor.go
@@ -15,8 +15,6 @@
 package image
 
 import (
-	"crypto/sha256"
-	"encoding/hex"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -24,6 +22,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/opencontainers/go-digest"
 	"github.com/pkg/errors"
 )
 
@@ -116,8 +115,13 @@ func (d *descriptor) validate(w walker, mts []string) error {
 }
 
 func (d *descriptor) validateContent(r io.Reader) error {
-	h := sha256.New()
-	n, err := io.Copy(h, r)
+	parsed, err := digest.Parse(d.Digest)
+	if err != nil {
+		return err
+	}
+
+	verifier := parsed.Verifier()
+	n, err := io.Copy(verifier, r)
 	if err != nil {
 		return errors.Wrap(err, "error generating hash")
 	}
@@ -126,9 +130,7 @@ func (d *descriptor) validateContent(r io.Reader) error {
 		return errors.New("size mismatch")
 	}
 
-	digest := "sha256:" + hex.EncodeToString(h.Sum(nil))
-
-	if digest != d.Digest {
+	if !verifier.Verified() {
 		return errors.New("digest mismatch")
 	}
 
diff --git a/image/image_test.go b/image/image_test.go
index e8e7284..35ecb29 100644
--- a/image/image_test.go
+++ b/image/image_test.go
@@ -18,8 +18,6 @@ import (
 	"archive/tar"
 	"bytes"
 	"compress/gzip"
-	"crypto/sha256"
-	"fmt"
 	"io"
 	"io/ioutil"
 	"os"
@@ -28,6 +26,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/opencontainers/go-digest"
 	"github.com/opencontainers/image-spec/specs-go/v1"
 )
 
@@ -298,14 +297,16 @@ func createHashedBlob(name string) (descriptor, error) {
 		return descriptor{}, err
 	}
 
-	// Rename the file to hashed-digest name.
-	err = os.Rename(name, filepath.Join(filepath.Dir(name), desc.Digest))
+	parsed, err := digest.Parse(desc.Digest)
 	if err != nil {
 		return descriptor{}, err
 	}
 
-	//Normalize the hashed digest.
-	desc.Digest = "sha256:" + desc.Digest
+	// Rename the file to hashed-digest name.
+	err = os.Rename(name, filepath.Join(filepath.Dir(name), parsed.Hex()))
+	if err != nil {
+		return descriptor{}, err
+	}
 
 	return desc, nil
 }
@@ -317,15 +318,14 @@ func newDescriptor(name string) (descriptor, error) {
 	}
 	defer file.Close()
 
-	// generate sha256 hash
-	hash := sha256.New()
-	size, err := io.Copy(hash, file)
+	digester := digest.SHA256.Digester()
+	size, err := io.Copy(digester.Hash(), file)
 	if err != nil {
 		return descriptor{}, err
 	}
 
 	return descriptor{
-		Digest: fmt.Sprintf("%x", hash.Sum(nil)),
+		Digest: digester.Digest().String(),
 		Size:   size,
 	}, nil
 }
diff --git a/image/manifest_test.go b/image/manifest_test.go
index 81242e1..b75ac0a 100644
--- a/image/manifest_test.go
+++ b/image/manifest_test.go
@@ -18,14 +18,14 @@ import (
 	"archive/tar"
 	"bytes"
 	"compress/gzip"
-	"crypto/sha256"
-	"fmt"
 	"io"
 	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
 	"testing"
+
+	"github.com/opencontainers/go-digest"
 )
 
 func TestUnpackLayerDuplicateEntries(t *testing.T) {
@@ -90,18 +90,17 @@ func TestUnpackLayer(t *testing.T) {
 	gw.Close()
 	f.Close()
 
-	// generate sha256 hash
-	h := sha256.New()
+	digester := digest.SHA256.Digester()
 	file, err := os.Open(tarfile)
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer file.Close()
-	_, err = io.Copy(h, file)
+	_, err = io.Copy(digester.Hash(), file)
 	if err != nil {
 		t.Fatal(err)
 	}
-	err = os.Rename(tarfile, filepath.Join(tmp1, "blobs", "sha256", fmt.Sprintf("%x", h.Sum(nil))))
+	err = os.Rename(tarfile, filepath.Join(tmp1, "blobs", "sha256", digester.Digest().Hex()))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -109,7 +108,7 @@ func TestUnpackLayer(t *testing.T) {
 	testManifest := manifest{
 		Layers: []descriptor{descriptor{
 			MediaType: "application/vnd.oci.image.layer.v1.tar+gzip",
-			Digest:    fmt.Sprintf("sha256:%s", fmt.Sprintf("%x", h.Sum(nil))),
+			Digest:    digester.Digest().String(),
 		}},
 	}
 	err = testManifest.unpack(newPathWalker(tmp1), filepath.Join(tmp1, "rootfs"))
@@ -151,18 +150,17 @@ func TestUnpackLayerRemovePartialyUnpackedFile(t *testing.T) {
 	gw.Close()
 	f.Close()
 
-	// generate sha256 hash
-	h := sha256.New()
+	digester := digest.SHA256.Digester()
 	file, err := os.Open(tarfile)
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer file.Close()
-	_, err = io.Copy(h, file)
+	_, err = io.Copy(digester.Hash(), file)
 	if err != nil {
 		t.Fatal(err)
 	}
-	err = os.Rename(tarfile, filepath.Join(tmp1, "blobs", "sha256", fmt.Sprintf("%x", h.Sum(nil))))
+	err = os.Rename(tarfile, filepath.Join(tmp1, "blobs", "sha256", digester.Digest().Hex()))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -170,7 +168,7 @@ func TestUnpackLayerRemovePartialyUnpackedFile(t *testing.T) {
 	testManifest := manifest{
 		Layers: []descriptor{descriptor{
 			MediaType: "application/vnd.oci.image.layer.v1.tar+gzip",
-			Digest:    fmt.Sprintf("sha256:%s", fmt.Sprintf("%x", h.Sum(nil))),
+			Digest:    digester.Digest().String(),
 		}},
 	}
 	err = testManifest.unpack(newPathWalker(tmp1), filepath.Join(tmp1, "rootfs"))