diff --git a/aes_siv.go b/aes_siv.go
index 7ba706e..3b20458 100644
--- a/aes_siv.go
+++ b/aes_siv.go
@@ -23,6 +23,8 @@ var (
 	ErrSivUnWrapSizeUnsupportedCiphertext = errors.New("Siv Unwrap error: ciphertext size is longer than supported")
 	//ErrSivUnWrapUnsupportedAdditionalData indicates that the additionalData elements supplied exceed the maximum number supported
 	ErrSivUnWrapUnsupportedAdditionalData = errors.New("Siv Unwrap error: additionalData elements more than than supported")
+	//ErrSivUnWrapShortCipherLength indicates that the cipher text is too short
+	ErrSivUnWrapShortCipherLength = errors.New("Siv Unwrap error: ciphertext is too short")
 )
 
 const (
@@ -68,6 +70,9 @@ func (c *aesSiv) Unwrap(ciphertext []byte, additionalData ...[]byte) ([]byte, er
 	if len(ciphertext)-ctrBlockSize > (1 << (strconv.IntSize - 3)) {
 		return nil, ErrSivUnWrapSizeUnsupportedCiphertext
 	}
+	if len(ciphertext) < cmacBlockSize {
+		return nil, ErrSivUnWrapShortCipherLength
+	}
 	if len(additionalData) > (cmacBlockSize*8)-2 {
 		return nil, ErrSivUnWrapUnsupportedAdditionalData
 	}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..a3284ee
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,5 @@
+module github.com/ChandraNarreddy/siv
+
+go 1.16
+
+require github.com/aead/cmac v0.0.0-20160719120800-7af84192f0b1
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..f918b9e
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,2 @@
+github.com/aead/cmac v0.0.0-20160719120800-7af84192f0b1 h1:+JkXLHME8vLJafGhOH4aoV2Iu8bR55nU6iKMVfYVLjY=
+github.com/aead/cmac v0.0.0-20160719120800-7af84192f0b1/go.mod h1:nuudZmJhzWtx2212z+pkuy7B6nkBqa+xwNXZHL1j8cg=