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

[s7r]

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.

[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

Post by s7r
Hello,
According to
/tor/src/core/mainloop/connection.c
/* 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.