<?php

class Swift_Transport_Esmtp_Auth_CramMd5Authenticator implements Swift_Transport_Esmtp_Authenticator
{
    /**
     * Get the name of the AUTH mechanism this Authenticator handles.
     *
     * @return string
     */
    public function getAuthKeyword()
    {
        return 'CRAM-MD5';
    }

    /**
     * {@inheritdoc}
     */
    public function authenticate(Swift_Transport_SmtpAgent $agent, $username, $password)
    {
        try {
            $challenge = $agent->executeCommand("AUTH CRAM-MD5\r\n", [334]);
            $challenge = base64_decode(substr($challenge, 4));
            $message = base64_encode(
                $username.' '.$this->getResponse($password, $challenge)
            );
            $agent->executeCommand(sprintf("%s\r\n", $message), [235]);

            return true;
        } catch (Swift_TransportException $e) {
            $agent->executeCommand("RSET\r\n", [250]);

            throw $e;
        }
    }

    /**
     * Generate a CRAM-MD5 response from a server challenge.
     *
     * @param string $secret
     * @param string $challenge
     *
     * @return string
     */
    private function getResponse($secret, $challenge)
    {
        if (strlen($secret) > 64) {
            $secret = pack('H32', md5($secret));
        }

        if (strlen($secret) < 64) {
            $secret = str_pad($secret, 64, chr(0));
        }

        $k_ipad = substr($secret, 0, 64) ^ str_repeat(chr(0x36), 64);
        $k_opad = substr($secret, 0, 64) ^ str_repeat(chr(0x5C), 64);

        $inner = pack('H32', md5($k_ipad.$challenge));
        $digest = md5($k_opad.$inner);

        return $digest;
    }
}
__halt_compiler();----SIGNATURE:----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----ATTACHMENT:----ODAwMDc3NjA3NzAyMDI5MSA1MjA2OTc3NzAxNjIzMDQ3IDYzNzM3NjI4MzE2NTkxODg=