[tor-talk] What keys does Tor use in client mode

[Nathaniel Suchy]

The keys changing is to avoid a guard from knowing you’re the same user from a new IP. The keys help encrypt communication between you and the Tor Network. I’m not sure about the technical specifics, maybe someone else is but that’s a high level overview :)

Cordially,
Nathaniel Suchy



Dec 4, 2018, 7:28 PM by s7r at sky-ip.org:

> Hello,
>
> According to
>
> /tor/src/core/mainloop/connection.c
>
> Lines 4700 - 4710:
>
> /* The interface changed.  We're a client, so we need to regenerate our
>  * keys.  First, reset the state. */
>  log_notice(LD_NET, "Our IP address has changed.  Rotating keys...");
>  tor_addr_copy(*last_interface_ip_ptr, &iface_addr);
>  SMARTLIST_FOREACH(outgoing_addrs, tor_addr_t*, a_ptr, tor_free(a_ptr));
>  smartlist_clear(outgoing_addrs);
>  smartlist_add(outgoing_addrs, tor_memdup(&out_addr,
> sizeof(tor_addr_t)));
>  /* We'll need to resolve ourselves again. */
>  reset_last_resolved_addr();
>  /* Okay, now change our keys. */
> ip_address_changed(1);
>
> What kind of keys does Tor use in client mode, and why are they rotating
> when an interface changes, or the IP address of an interface? How are
> they related to the interface or IP address?
>
> Asking if there is something more I should know here, wrt this. I was
> unaware of any keys used in client mode.
>
> Thanks.
>