How to securely generate an IV for AES CBC Encryption?

Question

I work on some crypto stuff.

• I use AES 256 with CBC mode
• I use OPENSSL

I am aware of the following things (source = wikipedia):

Answer 1

Just more comfortable to use the same stuff that Thomas sujested:

private function genIv()
{
    $efforts = 0;
    $maxEfforts = 50;
    $wasItSecure = false;

    do
    {
        $efforts+=1;
        $iv = openssl_random_pseudo_bytes(16, $wasItSecure);
        if($efforts == $maxEfforts){
            throw new Exception('Unable to genereate secure iv.');
            break;
        }
    } while (!$wasItSecure);

    return $iv;
}