diff --git a/app/js/lib/bin_utils.js b/app/js/lib/bin_utils.js
index d59b2abe..d8a21b65 100644
--- a/app/js/lib/bin_utils.js
+++ b/app/js/lib/bin_utils.js
@@ -43,9 +43,15 @@ function bytesToHex (bytes) {
 function bytesFromHex (hexString) {
   var len = hexString.length,
       i,
+      start = 0,
       bytes = [];
 
-  for (i = 0; i < len; i += 2) {
+  if (hexString.length % 2) {
+    bytes.push(parseInt(hexString.charAt(0), 16));
+    start++;
+  }
+
+  for (i = start; i < len; i += 2) {
     bytes.push(parseInt(hexString.substr(i, 2), 16));
   }
 
@@ -575,7 +581,7 @@ function bytesModPow (x, y, m) {
   try {
     var xBigInt = str2bigInt(bytesToHex(x), 16),
         yBigInt = str2bigInt(bytesToHex(y), 16),
-        mBigInt = str2bigInt(bytesToHex(m), 16, 2),
+        mBigInt = str2bigInt(bytesToHex(m), 16),
         resBigInt = powMod(xBigInt, yBigInt, mBigInt);
 
     return bytesFromHex(bigInt2str(resBigInt, 16));