4 ms·
why is the picture not simply cached near the sender as opposed to the receiver? is there any good reason for deciding this way on the part of Signal et al?
by jdthedisciple 2y ago
why is the picture not simply cached near the sender as opposed to the receiver?
is there any good reason for deciding this way on the part of Signal et al?
- pornel 2y agoThe attacker can't be forced to make a request. In this PoC the attacker disabled their own outgoing image requests. But that wouldn't help anyway, even if the image could be cached near the sender first, or the signal server prewarmed some other cache. After the victim opened the image, the attacker would see two locations that have the image cached, and could easily deduce which one is the victim's location (e.g. if Signal pre-warmed a random cache, repeating the attack a couple of times would be enough to eliminate the randomness).
- mmooss 2y agoIt's cached near the receiver for performance purposes, I assume, the same reason Cloudflare uses geographically local caches.