Add CryptoUtils class.

lib/crypto/crypto.dart

Index: lib/crypto/crypto.dart
diff --git a/lib/crypto/crypto.dart b/lib/crypto/crypto.dart
index f17c0f0e9c9c9d79aae83e3357eca9d592f381ae..ba4f61df7d74d6bc0e6de6c0d547177e49c87dee 100644
--- a/lib/crypto/crypto.dart
+++ b/lib/crypto/crypto.dart
@@ -4,6 +4,7 @@
 
 #library('crypto');
 
+#source('crypto_utils.dart');
 #source('hmac.dart');
 #source('sha_utils.dart');
 #source('sha1.dart');
@@ -59,7 +60,6 @@ interface SHA256 extends Hash default _SHA256 {
   SHA256();
 }
 
-
 /**
  * Hash-based Message Authentication Code support.
  *
@@ -84,6 +84,18 @@ interface HMAC default _HMAC {
   List<int> digest();
 }
 
+/**
+ * Utility methods for working with message digests.
+ */
+class CryptoUtils {
+  /**
+   * Convert a message digest which is a list of bytes into a hex
+   * string.
+   */
+  static String digestToHex(List<int> digest) {

[Søren Gjesse, 2012/05/07 14:26:34]

Shouldn't this just be bytesToHex? This can be used for more than just digests.
For crypto input can also be for instance keys.

[Mads Ager (google), 2012/05/07 14:34:59]

Good point. Done.

+    return _CryptoUtils.digestToHex(digest);
+  }
+}
 
 /**
  * HashExceptions are thrown on invalid use of a Hash