code: public function encryptByKey($data, $inputKey, $info = null)
      {
          return $this->encrypt($data, false, $inputKey, $info);
      }
docs: Encrypts data using a cryptographic key.
  Derives keys for encryption and authentication from the input key using HKDF and a random salt,
  which is very fast relative to [[encryptByPassword()]]. The input key must be properly
  random -- use [[generateRandomKey()]] to generate keys.
  The encrypted data includes a keyed message authentication code (MAC) so there is no need
  to hash input or output data.
  @param string $data the data to encrypt
  @param string $inputKey the input to use for encryption and authentication
  @param string $info optional context and application specific information, see [[hkdf()]]
  @return string the encrypted data
  @see decryptByKey()
  @see encryptByPassword()