Stop using parts.

lib/src/crypto_utils.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-part of crypto;
+library crypto.crypto_utils;
 
-abstract class _CryptoUtils {
+import 'base64.dart';
+
+/**
+ * Utility methods for working with message digests.
+ */
+abstract class CryptoUtils {
+  /**
+   * Convert a list of bytes (for example a message digest) into a hex
+   * string.
+   */
   static String bytesToHex(List<int> bytes) {
     var result = new StringBuffer();
     for (var part in bytes) {
       result.write('${part < 16 ? '0' : ''}${part.toRadixString(16)}');
     }
     return result.toString();
   }
 
+  /**
+   * Converts a list of bytes into a Base 64 encoded string.
+   *
+   * The list can be any list of integers in the range 0..255,
+   * for example a message digest.
+   *
+   * If [addLineSeparator] is true, the resulting string will  be
+   * broken into lines of 76 characters, separated by "\r\n".
+   *
+   * If [urlSafe] is true, the result is URL and filename safe.
+   *
+   * Based on [RFC 4648](http://tools.ietf.org/html/rfc4648)
+   *
+   */
   static String bytesToBase64(List<int> bytes,
       [bool urlSafe = false, bool addLineSeparator = false]) {
     return BASE64.encode(bytes,
         urlSafe: urlSafe, addLineSeparator: addLineSeparator);
   }
 
+  /**
+   * Converts a Base 64 encoded String into list of bytes.
+   *
+   * Decoder ignores "\r\n" sequences from input.
+   *
+   * Accepts both URL safe and unsafe Base 64 encoded strings.
+   *
+   * Throws a FormatException exception if input contains invalid characters.
+   *
+   * Based on [RFC 4648](http://tools.ietf.org/html/rfc4648)
+   */
   static List<int> base64StringToBytes(String input) {
     return BASE64.decode(input);
   }
 }