Update documentation comments.

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.
 
 library crypto.crypto_utils;
 
 import 'base64.dart';
 
-/**
- * Utility methods for working with message digests.
- */
+/// Utility methods for working with message digests.
 abstract class CryptoUtils {
-  /**
-   * Convert a list of bytes (for example a message digest) into a hex
-   * string.
-   */
+  /// Convert a list of bytes (for example a message digest) into a hexadecimal
+  /// 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)
-   *
-   */
+  /// Converts a list of bytes into a [Base64-encoded][rfc] string.
+  ///
+  /// [rfc]: https://tools.ietf.org/html/rfc4648
+  ///
+  /// The list can be any list of integers from 0 to 255 inclusive, 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 resulting string will be URL- and filename-
+  /// safe.
   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)
-   */
+  /// Converts a [Base64-encoded][rfc] String into list of bytes.
+  ///
+  /// [rfc]: https://tools.ietf.org/html/rfc4648
+  ///
+  /// This ignores "\r\n" sequences in [input]. It accepts both URL-safe and
+  /// -unsafe Base 64 encoded strings.
+  ///
+  /// Throws a [FormatException] if [input] contains invalid characters.
   static List<int> base64StringToBytes(String input) {
     return BASE64.decode(input);
   }
 }