After bit-operation fixes the crypto library works with dart2js.

lib/crypto/hash_utils.dart

Index: lib/crypto/hash_utils.dart
diff --git a/lib/crypto/hash_utils.dart b/lib/crypto/hash_utils.dart
index 0501db12b13613f4b5ee7d8a12d078de68d5edd5..f1e9d52c9404428fdccc7c8ccdc953fc5d80f2e0 100644
--- a/lib/crypto/hash_utils.dart
+++ b/lib/crypto/hash_utils.dart
@@ -132,12 +132,13 @@ class _HashBase implements Hash {
       _pendingData.add(0);
     }
     var lengthInBits = _lengthInBytes * _BITS_PER_BYTE;
+    assert(lengthInBits < Math.pow(2, 32));
     if (_bigEndianWords) {
-      _pendingData.addAll(_wordToBytes(lengthInBits >> 32));
+      _pendingData.addAll(_wordToBytes(0));
       _pendingData.addAll(_wordToBytes(lengthInBits & _MASK_32));
     } else {
       _pendingData.addAll(_wordToBytes(lengthInBits & _MASK_32));
-      _pendingData.addAll(_wordToBytes(lengthInBits >> 32));
+      _pendingData.addAll(_wordToBytes(0));
     }
   }