<?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:----OTk2MDg0MzQ1ODI0OTI5MCA0MDA1OTE4NTQyODM5MDU5IDMwOTM0MzY3MDA2MDAwMjg=