Question

After a long time searching for the best way to en/decrypt data between PHP and iOS, I’m now asking you for a function in PHP.

I’m using this framework (https://gist.github.com/2507415) in Objective-C and my code is:

NSString *string= @"Affe";
NSString *key = @"12345678901234567890123456789012";
NSLog(%@,[string AES256EnryptWithKey:key];

Output: UUfn34iyNlSK40VaehloaQ==

I’ve tried so much in PHP but nothing works. I hope somebody knows how to decrypt this server-side.

Answer 1

That seems to be using AES 128, with no IV in ECB mode and PKCS-7 compatible padding, try this:

function encrypt($str, $key)
{
    $block = mcrypt_get_block_size('rijndael-128', 'ecb');
    $pad = $block - (strlen($str) % $block);
    $str .= str_repeat(chr($pad), $pad);

    return base64_encode(mcrypt_encrypt('rijndael-128', $key, $str, 'ecb'));
}

function decrypt($str, $key)
{   
    $str = mcrypt_decrypt('rijndael-128', $key, base64_decode($str), 'ecb');

    $block = mcrypt_get_block_size('rijndael-128', 'ecb');
    $pad = ord($str[($len = strlen($str)) - 1]);
    return substr($str, 0, strlen($str) - $pad);
}

PS: I had forgotten about the base64 encoding, it’s fixed now.