lib/classes/Swift/Transport/Esmtp/Auth/NTLMAuthenticator.php
protected function md4Encrypt($input)
    {
        $input = $this->convertTo16bit($input);

        return function_exists('hash') ? hex2bin(hash('md4', $input)) : mhash(MHASH_MD4, $input);
    }
protected function md4Encrypt($input)
    {
        $input = $this->convertTo16bit($input);

        return function_exists('hash') ? hex2bin(hash('md4', $input)) : mhash(MHASH_MD4, $input);
    }
protected function md4Encrypt ( $ input ) { $ input = $ this -> convertTo16bit ( $ input ) ; return function_exists ( 'hash' ) ? hex2bin ( hash ( 'md4' , $ input ) ) : mhash ( MHASH_MD4 , $ input ) ; }
MD4 Encryption.

@param string $input

@return string

@see https://secure.php.net/manual/en/ref.hash.php
MD4 Encryption .