code: public function calculateLmResponse(
          HashCredentialInterface $hash_credential,
          $client_challenge,
          $server_challenge_nonce
      ) {
          $data_to_hash = ($server_challenge_nonce . $client_challenge);
  
          $keyed_hasher = $this->crypt_hasher_factory->build(
              static::KEYED_HASHER_ALGORITHM,
              $hash_credential->getValue()
          );
  
          $keyed_hash_result = $keyed_hasher->update($data_to_hash)->digest();
  
          return ($keyed_hash_result . $client_challenge);
      }
docs: Calculates the LM response.
  
  @param HashCredentialInterface $hash_credential The user's authentication
  LM hash credential.
  @param string $client_challenge A randomly generated 64-bit (8-byte)
  unsigned client-generated binary string.
  @param string $server_challenge_nonce The 64-bit (8-byte) unsigned
  server-sent "nonce" (number used once) represented as a binary string.
  @return string The calculated response as a binary string.