Merge pull request #2428 from zhouhaibing089/algo-import

cmd/digest: import crypto algorithms

cmd/digest/main.go

@@ -9,6 +9,9 @@ import (
 
 	"github.com/docker/distribution/version"
 	"github.com/opencontainers/go-digest"
+
+	_ "crypto/sha256"
+	_ "crypto/sha512"
 )
 
 var (