Utility methods for working with message digests.

class CryptoUtils {
 /**
  * Convert a list of bytes (for example a message digest) into a hex
  * string.
  */
 static String bytesToHex(List<int> bytes) {
   return _CryptoUtils.bytesToHex(bytes);
 }

 /**
  * 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 _CryptoUtils.bytesToBase64(bytes,
                                     urlSafe,
                                     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 _CryptoUtils.base64StringToBytes(input);
 }
}