code: public static String decrypt(String key, String source) {
          try {
              // Get our secret key
              Key key0 = getKey(key);
              // Create the cipher
              Cipher desCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
  
              //byte[] b64cipherText = StringUtil.getAsciiBytes(source);
              // convert source string into base 64 bytes
              //byte[] ciphertext = Base64.decodeBase64(b64cipherText);
              // replaced Jakarta Base64 with custom one
              byte[] ciphertext = Base64Codec.decode(source);
  
              // Initialize the same cipher for decryption
              desCipher.init(Cipher.DECRYPT_MODE, key0);
              // Decrypt the ciphertext
              byte[] cleartext = desCipher.doFinal(ciphertext);
              // Return the clear text
              return new String(cleartext);
          } catch (Exception e) {
              throw new RuntimeException(e.getMessage());
          }
      }
docs: Decodes a base-64 encoded string using the key with the DES/ECB/PKCS5Padding
  cipher.
  @param key The key to use for encryption. Must be at least 8 characters
  in length.
  @param source The Base-64 encoded encypted string.
  @return The plain text