code: func aesTransform(dst []byte, src []byte, direction directionConst, bc cipher.Block) {
  	if direction == DirectionEncrypt {
  		bc.Encrypt(dst, src)
  		return
  	} else if direction == DirectionDecrypt {
  		bc.Decrypt(dst, src)
  		return
  	}
  }
docs: // aesTransform - encrypt or decrypt (according to "direction") using block
  // cipher "bc" (typically AES)