I think following function doesn’t need any more description but the inline comments.

The Function:

// f(ucking) u(ncrackable) e(ncryption) function
function fue($hash,$times){
    // Execute the encryptions as many times as the user wants
    for($i=$times;$i>0;$i--) {
        // Encode with base64...
        $hash=base64_encode($hash);
        // and md5...
        $hash=md5($hash);
        // sha1...
        $hash=sha1($hash);
        // sha256... (one more)
        $hash=hash("sha256", $hash);
        // sha512
        $hash=hash("sha512", $hash);
    }
    // Finaly, when done, return the value
    return $hash;
}

This function was first introduced by BlackHatDBL.