In the 2021 movie Silk Road, at around 19:23-19:26 into the film we can see Ross Ulbricht, the lead character, write a program on his laptop that uses curl. A few seconds we get a look at the screen as Ross types on the keyboard and explains to the female character who says I didn’t know you know how to code that he’s teaching himself to write code.

The code

Let’s take a look at the code on the screen. This is PHP code using the well known PHP/CURL binding. The URL on the screen on line two has really bad contrast, but I believe this is what it says:

<?php
  $ch = curl_init("http://silkroadvb5pzir.onion");
  $ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, $url);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($ch, CURLOPT_PROXY,                
              "http://127.0.0.1:9050/");
  curl_setopt($ch, CURLOPT_PROXYTYPE, 7);
  $output = curl_exec($ch);
  $curl_error = curl_error($ch);
  curl_cl

.onion is a TLD for websites on Tor so this seems legit as it a URL for this purpose could look like this. But then Ross confuses matters a little. He uses two curl_init() calls, one that sets a URL and then again a call without a URL. He could just have removed line three and four. This doesn’t prohibit the code from working, it just wouldn’t have passed a review.

The code then sets a proxy to use for the transfer, specified as an HTTP URL which is a little odd since the proxy type he then sets on the line below is 7, the number corresponding to CURLPROXY_SOCKS5_HOSTNAME – so not a HTTP proxy at all but a SOCKS5 proxy. The typical way you access Tor: as a SOCKS5 proxy to which you pass the host name, as opposed to resolving the host name locally.

The last line is incomplete but should ultimately be curl_close($ch); to close the handle after use.

All in all a seemingly credible piece of code, especially if we consider it as a work in progress code. The minor mistakes would be soon be fixed.

Credits

Viktor Szakats spotted this and sent me the screenshot above. Thanks!