Looking at the technical writeup [1] it sounds like they're currently running a hybrid of the two as they do a staged rollout of the various changes they've mad

Looking at the technical writeup [1] it sounds like they're currently running a hybrid of the two as they do a staged rollout of the various changes they've made to the Signal Protocol. But yes you are correct it looks like they're justifying ditching PFS by saying "if someone has your keys you're screwed anyway." However they're not just stripping away security outright, it's more that they're betting on onion routing to cover the user instead - no one who is sniffing traffic on your WiFi network will be able to get your keys because the traffic is routed through the onion network, therefore the only way anyone would get those keys is by pwning your entire device or having physical access to it while it's decrypted which, as they note, is endgame no matter what messenger you use. I don't necessarily think this is smart as it's best to not put all your eggs in one basket especially where security is concerned. But given all traffic goes between 5-7 nodes [1] the scope for someone without remote or physical access to your device to get your keys is extremely limited assuming their onion network is as secure as they claim. As for deniability, they sign the message with the long-term keypair, but once the message is validated this signature is wiped. So again it pretty much comes down to relying on their onion routing to ensure this signature isn't intercepted in transit. Finally I think it's relevant Session is really designed for a different use case than Signal - since your ID is not connected to any personal identifiers, you can wipe it whenever you want and get a new ID that has zero cryptographic connection to the old one. So while there's no ratcheting of keys, the intention isn't really for someone to stick with the same account for years like it is for Signal where your account uses your phone number as an identifier. I'll wait for the results of the audit, if they come out and say Session is fundamentally flawed I'll happily concede. I have zero ties to this project aside from finding it useful for particular use cases. My prediction is the initial audit will find some potential vulns as they roll out more of the Session Protocol simply because it's a new fork. Probably why they're getting the audit done now. That's the responsible move when forking a crypto protocol it seems to me. I maintain that for people who want a messenger that knows as little about them as possible, doesn't rely on a personal identifier, and connects to an onion router reliably (by comparison, using Tor on mobile is... not a good experience) it's at very least an interesting project to watch even if it still needs time to mature. [1] https://getsession.org/session-protocol-technical-information/ https://getsession.org/session-protocol-technical-informatio...