diff --git a/cmd/duffle/build.go b/cmd/duffle/build.go
index 39f53d01..3d593dd4 100644
--- a/cmd/duffle/build.go
+++ b/cmd/duffle/build.go
@@ -133,7 +133,7 @@ func (b *buildCmd) run() (err error) {
 		return fmt.Errorf("cannot prepare build: %v", err)
 	}
 
-	if err := bldr.Build(ctx, app); err != nil {
+	if err := bldr.Build(ctx, app, bf); err != nil {
 		return err
 	}
 
diff --git a/cmd/duffle/export.go b/cmd/duffle/export.go
index d4032cf3..7f6ee66f 100644
--- a/cmd/duffle/export.go
+++ b/cmd/duffle/export.go
@@ -40,6 +40,7 @@ type exportCmd struct {
 	verbose      bool
 	insecure     bool
 	bundleIsFile bool
+	signer       string
 }
 
 func newExportCmd(w io.Writer) *cobra.Command {
diff --git a/pkg/builder/builder.go b/pkg/builder/builder.go
index ff4710cc..a0a5c425 100644
--- a/pkg/builder/builder.go
+++ b/pkg/builder/builder.go
@@ -7,8 +7,6 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
-	"sync"
-	"time"
 
 	"github.com/Masterminds/semver"
 	"github.com/pkg/errors"
@@ -87,11 +85,6 @@ func (b *Builder) PrepareBuild(bldr *Builder, mfst *manifest.Manifest, appDir st
 			return nil, nil, err
 		}
 
-		ii := bundle.InvocationImage{}
-		ii.Image = imb.URI()
-		ii.ImageType = imb.Type()
-		bf.InvocationImages = append(bf.InvocationImages, ii)
-
 		baseVersion := mfst.Version
 		if baseVersion == "" {
 			baseVersion = "0.1.0"
@@ -131,45 +124,27 @@ func (b *Builder) version(baseVersion, sha string) (string, error) {
 }
 
 // Build passes the context of each component to its respective builder
-func (b *Builder) Build(ctx context.Context, app *AppContext) error {
-	if err := buildInvocationImages(ctx, b.ImageBuilders, app); err != nil {
+func (b *Builder) Build(ctx context.Context, app *AppContext, bf *bundle.Bundle) error {
+	if err := b.buildInvocationImages(ctx, app, bf); err != nil {
 		return fmt.Errorf("error building image: %v", err)
 	}
 	return nil
 }
 
-func buildInvocationImages(ctx context.Context, imageBuilders []imagebuilder.ImageBuilder, app *AppContext) (err error) {
-	errc := make(chan error)
-
-	go func() {
-		defer close(errc)
-		var wg sync.WaitGroup
-		wg.Add(len(imageBuilders))
-
-		for _, c := range imageBuilders {
-			go func(c imagebuilder.ImageBuilder) {
-				defer wg.Done()
-				err = c.Build(ctx, app.Log)
-				if err != nil {
-					errc <- fmt.Errorf("error building image %v: %v", c.Name(), err)
-				}
-			}(c)
-		}
-
-		wg.Wait()
-	}()
-
-	for errc != nil {
-		select {
-		case err, ok := <-errc:
-			if !ok {
-				errc = nil
-				continue
-			}
+func (b *Builder) buildInvocationImages(ctx context.Context, app *AppContext, bf *bundle.Bundle) (err error) {
+	built := []bundle.InvocationImage{}
+	for _, c := range b.ImageBuilders {
+		digest, err := c.Build(ctx, app.Log)
+		if err != nil {
 			return err
-		default:
-			time.Sleep(time.Second)
 		}
+		ii := bundle.InvocationImage{}
+		ii.Image = c.URI()
+		ii.ImageType = c.Type()
+		ii.Digest = digest
+		built = append(built, ii)
 	}
+	bf.InvocationImages = built
+
 	return nil
 }
diff --git a/pkg/imagebuilder/docker/builder.go b/pkg/imagebuilder/docker/builder.go
index f0fc5e69..6de55c02 100644
--- a/pkg/imagebuilder/docker/builder.go
+++ b/pkg/imagebuilder/docker/builder.go
@@ -9,9 +9,6 @@ import (
 	"os"
 	"path"
 	"path/filepath"
-	"strings"
-
-	"github.com/deislabs/duffle/pkg/duffle/manifest"
 
 	"github.com/docker/cli/cli/command"
 	"github.com/docker/cli/cli/command/image/build"
@@ -22,10 +19,11 @@ import (
 	"github.com/docker/docker/pkg/fileutils"
 	"github.com/docker/docker/pkg/jsonmessage"
 	"github.com/docker/docker/pkg/term"
-
 	"github.com/sirupsen/logrus"
-
 	"golang.org/x/net/context"
+
+	"github.com/deislabs/duffle/pkg/duffle/manifest"
+	"github.com/deislabs/duffle/pkg/imagebuilder/docker/digester"
 )
 
 const (
@@ -63,13 +61,6 @@ func (db Builder) URI() string {
 	return db.Image
 }
 
-// Digest returns the name of a Docker Builder, which will give the image name
-//
-// TODO - return the actual digest
-func (db Builder) Digest() string {
-	return strings.Split(db.Image, ":")[1]
-}
-
 // NewBuilder returns a new Docker builder based on the manifest
 func NewBuilder(c *manifest.InvocationImage, cli *command.DockerCli) *Builder {
 	return &Builder{
@@ -109,7 +100,7 @@ func (db *Builder) PrepareBuild(appDir, registry, name string) error {
 }
 
 // Build builds the docker images.
-func (db Builder) Build(ctx context.Context, log io.WriteCloser) error {
+func (db *Builder) Build(ctx context.Context, log io.WriteCloser) (string, error) {
 	defer db.BuildContext.Close()
 	buildOpts := types.ImageBuildOptions{
 		Tags:       []string{db.Image},
@@ -118,23 +109,33 @@ func (db Builder) Build(ctx context.Context, log io.WriteCloser) error {
 
 	resp, err := db.dockerBuilder.DockerClient.Client().ImageBuild(ctx, db.BuildContext, buildOpts)
 	if err != nil {
-		return fmt.Errorf("error building image builder %v with builder %v: %v", db.Name(), db.Type(), err)
+		return "", fmt.Errorf("error building image builder %v with builder %v: %v", db.Name(), db.Type(), err)
 	}
-
 	defer resp.Body.Close()
+
 	outFd, isTerm := term.GetFdInfo(db.BuildContext)
 	if err := jsonmessage.DisplayJSONMessagesStream(resp.Body, log, outFd, isTerm, nil); err != nil {
-		return fmt.Errorf("error streaming messages for image builder %v with builder %v: %v", db.Name(), db.Type(), err)
+		return "", fmt.Errorf("error streaming messages for image builder %v with builder %v: %v", db.Name(), db.Type(), err)
 	}
 
 	if _, _, err = db.dockerBuilder.DockerClient.Client().ImageInspectWithRaw(ctx, db.Image); err != nil {
 		if dockerclient.IsErrNotFound(err) {
-			return fmt.Errorf("could not locate image for %s: %v", db.Name(), err)
+			return "", fmt.Errorf("could not locate image for %s: %v", db.Name(), err)
 		}
-		return fmt.Errorf("imageInspectWithRaw error for image builder %v: %v", db.Name(), err)
+		return "", fmt.Errorf("imageInspectWithRaw error for image builder %v: %v", db.Name(), err)
 	}
 
-	return nil
+	d := digester.NewDigester(
+		db.dockerBuilder.DockerClient.Client(),
+		db.Image,
+		ctx,
+	)
+	digestStr, err := d.Digest()
+	if err != nil {
+		return "", fmt.Errorf("Failed to calculate digest for image: %s", err)
+	}
+
+	return digestStr, nil
 }
 
 func archiveSrc(contextPath string, b *Builder) error {
diff --git a/pkg/imagebuilder/docker/digester/digester.go b/pkg/imagebuilder/docker/digester/digester.go
new file mode 100644
index 00000000..372052bc
--- /dev/null
+++ b/pkg/imagebuilder/docker/digester/digester.go
@@ -0,0 +1,39 @@
+package digester
+
+import (
+	"golang.org/x/net/context"
+
+	"github.com/docker/docker/client"
+	"github.com/opencontainers/go-digest"
+)
+
+type Digester struct {
+	Client  client.ImageAPIClient
+	Image   string
+	Context context.Context
+}
+
+// NewDigester returns a Digester given the args client, image, ctx
+//
+// client allows us to talk to the Docker client
+// image is a string identifier of the image we want to compute digest of
+// ctx is context to use and pass to Docker client
+func NewDigester(client client.ImageAPIClient, image string, ctx context.Context) *Digester {
+	return &Digester{
+		Client:  client,
+		Image:   image,
+		Context: ctx,
+	}
+}
+
+// Digest returns the digest of the image tar
+func (d *Digester) Digest() (string, error) {
+	reader, err := d.Client.ImageSave(d.Context, []string{d.Image})
+	computedDigest, err := digest.Canonical.FromReader(reader)
+	if err != nil {
+		return "", err
+	}
+	defer reader.Close()
+
+	return computedDigest.String(), nil
+}
diff --git a/pkg/imagebuilder/imagebuilder.go b/pkg/imagebuilder/imagebuilder.go
index 56280b25..9d318547 100644
--- a/pkg/imagebuilder/imagebuilder.go
+++ b/pkg/imagebuilder/imagebuilder.go
@@ -10,8 +10,7 @@ type ImageBuilder interface {
 	Name() string
 	Type() string
 	URI() string
-	Digest() string
 
 	PrepareBuild(string, string, string) error
-	Build(context.Context, io.WriteCloser) error
+	Build(context.Context, io.WriteCloser) (string, error)
 }
diff --git a/pkg/imagebuilder/mock/builder.go b/pkg/imagebuilder/mock/builder.go
index 310bce27..7c16bee8 100644
--- a/pkg/imagebuilder/mock/builder.go
+++ b/pkg/imagebuilder/mock/builder.go
@@ -26,11 +26,6 @@ func (b Builder) URI() string {
 	return "mock-uri:1.0.0"
 }
 
-// Digest represents the digest of a mock builder
-func (b Builder) Digest() string {
-	return "mock-digest"
-}
-
 // NewBuilder returns a new mock builder
 func NewBuilder(c *manifest.InvocationImage) *Builder {
 	return &Builder{}
@@ -42,6 +37,6 @@ func (b *Builder) PrepareBuild(appDir, registry, name string) error {
 }
 
 // Build is no-op for a mock builder
-func (b Builder) Build(ctx context.Context, log io.WriteCloser) error {
-	return nil
+func (b Builder) Build(ctx context.Context, log io.WriteCloser) (string, error) {
+	return "mock-digest", nil
 }