proper PHP mcrypt encryption methods?

Question

Ok, I have tried to create my own encryption/decryption methods using PHP mcrypt, and when I posted them a while back some called them \"trash\". They were ment

Answer 1

You can create an iv with mcrypt_create_iv(), using the appropriate size for your encryption mode.

$size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_192, MCRYPT_MODE_CBC);
$iv = mcrypt_create_iv($size, MCRYPT_DEV_RANDOM);

Then pass it to mcrypt_cbc() as the optional 5th parameter. The only changes I've made here to your original functions are to pass in $iv:

function encrypt($key, $data, $iv){
    $encrypted_data = mcrypt_cbc(MCRYPT_RIJNDAEL_192, $key, $data, MCRYPT_ENCRYPT, $iv);
    return base64_encode($encrypted_data);
}

function decrypt($key, $encryptedData, $iv){
    $dec = base64_decode($encryptedData);
    $decrypt = mcrypt_cbc(MCRYPT_RIJNDAEL_192, $key, $dec, MCRYPT_DECRYPT, $iv);
    return trim($decrypt);
}