diff --git a/stream/blob.go b/stream/blob.go
index 146cd1f..1cbd8c9 100644
--- a/stream/blob.go
+++ b/stream/blob.go
@@ -11,7 +11,11 @@ import (
 	"github.com/lbryio/lbry.go/extras/errors"
 )
 
-const MaxBlobSize = 2097152 // 2mb, or 2 * 2^20
+const (
+	MaxBlobSize       = 2097152 // 2mb, or 2 * 2^20
+	BlobHashSize      = sha512.Size384
+	BlobHashHexLength = BlobHashSize * 2 // in hex, each byte is 2 chars
+)
 
 type Blob []byte