<?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:----Njk0MDYxODg4OTgyNDcxMCA0NzMwMDUxOTYzOTU1NTg5IDUxODY5MDgzNjAyOTQ0Mzk=