From 06608318d4215ff9320de9630df1848853b803fe Mon Sep 17 00:00:00 2001
From: Daniel Huigens <d.huigens@protonmail.com>
Date: Wed, 12 Dec 2018 17:48:23 +0100
Subject: [PATCH] Fix CMAC of the empty string

This is currently never called, as EAX always adds a prefix to
the CMAC'ed message.
---
 src/crypto/cmac.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/crypto/cmac.js b/src/crypto/cmac.js
index b6d31ec7..d3675fbd 100644
--- a/src/crypto/cmac.js
+++ b/src/crypto/cmac.js
@@ -48,7 +48,7 @@ function rightXorMut(data, padding) {
 
 function pad(data, padding, padding2) {
   // if |M| in {n, 2n, 3n, ...}
-  if (data.length % blockLength === 0) {
+  if (data.length && data.length % blockLength === 0) {
     // then return M xor→ B,
     return rightXorMut(data, padding);
   }