diff --git a/src/util.js b/src/util.js
index 25ba5cd0..a1d5c3d2 100644
--- a/src/util.js
+++ b/src/util.js
@@ -154,18 +154,10 @@ const util = {
    * @returns {String} Hexadecimal representation of the array.
    */
   uint8ArrayToHex: function (bytes) {
-    const r = [];
-    const e = bytes.length;
-    let c = 0;
-    let h;
-    while (c < e) {
-      h = bytes[c++].toString(16);
-      while (h.length < 2) {
-        h = '0' + h;
-      }
-      r.push('' + h);
-    }
-    return r.join('');
+    const hexAlphabet = '0123456789abcdef';
+    let s = '';
+    bytes.forEach(v => { s += hexAlphabet[v >> 4] + hexAlphabet[v & 15]; });
+    return s;
   },
 
   /**
diff --git a/test/crypto/cipher/des.js b/test/crypto/cipher/des.js
index e3a00285..8cfc03b5 100644
--- a/test/crypto/cipher/des.js
+++ b/test/crypto/cipher/des.js
@@ -80,7 +80,7 @@ export default () => describe('TripleDES (EDE) cipher test with test vectors fro
       expect(encr, 'vector with block ' + util.uint8ArrayToHex(testvectors[i][0]) +
                    ' and key ' + util.uint8ArrayToHex(key) +
                    ' should be ' + util.uint8ArrayToHex(testvectors[i][1]) +
-                   ' != ' + util.uint8ArrayToHex(encr)).to.be.equal(util.uint8ArrayToString(testvectors[i][1]));
+                   ' != ' + encr).to.be.equal(util.uint8ArrayToString(testvectors[i][1]));
     }
     done();
   });