1 files changed, 6 insertions, 0 deletions
diff --git a/cmac.cpp b/cmac.cpp
index f8570a7f..ca04d0bd 100644
--- a/cmac.cpp
+++ b/cmac.cpp
@@ -31,9 +31,15 @@ static void MulU(byte *k, unsigned int length)
 			k[15] ^= 0x87;
 			break;
 		case 32:
+			// Should this be 0x425?
 			k[30] ^= 4;
 			k[31] ^= 0x23;
 			break;
+		case 64:
+			// https://crypto.stackexchange.com/q/9815/10496
+			k[62] ^= 1;
+			k[63] ^= 0x25;
+			break;
 		default:
 			throw InvalidArgument("CMAC: " + IntToString(length) + " is not a supported cipher block size");
 		}