Question

I need to encrypt a string using MySQL’s AES_ENCRYPT function, then attach that encrypted string to the end of a URL, such that it can then be decrypted and used by a PHP script on the other end.

Basically, I am encrypting the string (using MySQL’s AES_ENCRYPT), I am then using PHP’s rawurlencode() function to make it “URL safe”. I then pass the encrypted string in a URL, which is then retrieved by the PHP script on the other end where it gets successfully decrypted… about 95% of the time.

Seems as though about 5% of strings are encrypting in such a way that they are getting corrupted somewhere in the process, and can’t be decoded on the other end after being passed by a URL. Can anyone help me out here? Is there a 100% fool-proof way to do this? I have also tried using urlencode() as well as base64_encode() in varying combinations.

Thanks.

Answer 1

Solved.

Once I have encrypted the string using MySQL’s AES_ENCRYPT function, I use PHP’s bin2hex() function to convert that encrypted data (which is in binary form) in to Hexidecimal. I then pass the Hexidecimal as a string on the end of the URL. Once the URL is received on the other end, I then use this custom PHP function to revert the Hex string back to binary:

function hex2bin($data) {
    $len = strlen($data);
    return pack("H" . $len, $data);
}

From there, all that’s left to do is decrypt the data using MySQL’s AES_DECRYPT function, and wha-la. The original string is successfully restored.