Problem Generating Signature

[carpabg]

Hi, I had some problems generating the signature, as it seems to be wrong.

I've compared the result of the Ds_Signature and Ds_MerchantParams with a PHP Redsys Api which was working correctly. Finally I found the problem is how the signature is generate, in particular in the 3Des encryption step.

In the PHP API the result of the encryption is cropped by a multiplier (I don't know why).

protected static function encrypt3DESOpenSSL($message, $key)
{
        $l = ceil(strlen($message) / 8) * 8;
        $message = $message.str_repeat("\0", $l - strlen($message));

        return substr(openssl_encrypt($message, 'des-ede3-cbc', $key, OPENSSL_RAW_DATA, "\0\0\0\0\0\0\0\0"), 0, $l);
}

Changing the 3Des encyption method in the node api finanly I get redsys working.

encrypt3DES(str, key) {
    const secretKey = Buffer.from(key, 'base64');
    const iv = Buffer.alloc(8, 0);
    const cipher = crypto.createCipheriv('des-ede3-cbc', secretKey, iv);
    cipher.setAutoPadding(false);
    const en_key = cipher.update(zeroPad(str, 8), 'utf8', 'binary') + cipher.final('binary');
    const l = Math.ceil(str.length / 8) * 8;
    //$message = $message.str_repeat("\0", $l - strlen($message));
    return Buffer.from(en_key.substr(0, l), 'binary').toString('base64');
}