-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 18/11/14 16:23, Mike Hearn wrote: > I can see a couple of directions to go now: > > 1. Cracking the usable key verification problem. This move brings > WhatsApp to the same level of security as iMessage (or better, > given the forward security), but WhatsApp/Facebook could still do > a switcheroo on people's keys. TextSecure never really figured > this out IMO - it still expects people to manually compare long > strings of hex.
Fingerprint comparison can be made easy with QR codes. The tricky part is what to do when a user reinstalls the app, creating a new key. How do their contacts know the difference between that and a MITM attack? Maybe the answer is that they don't. There's no special UX for a MITM attack - no flashing red warning that the sky is falling. If the server MITMs a verified contact, they switch back to unverified, just as they would if they reinstalled. Caveat, uh, usor. > 2. Building a trustworthy binary auditing and distribution process, > so people can be assured that they're using what they think > they're using. I have some ideas on this and have been doing a bit > of work on it myself for Lighthouse, which features a threshold > signature based auto update system. But the bulk of this work > involves things like finding people who can be trusted to audit the > source code in a variety of jurisdictions, making the builds > reproducible, and finding a way to make the platform auto update > mechanisms thresholded. I have some threshold RSA code I was able > to extract from some academics a year or two ago that should in > theory be compatible with Android, but I never tested it. Do you need threshold signatures for this, or would a quorum of ordinary signatures work? Cheers, Michael -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQEcBAEBCAAGBQJUa6AxAAoJEBEET9GfxSfMVYAH/1cKR0CRmtMtYipzS0SQZN/P iJVO98NwzQYFodgrTQiL/aImYhhUoTrBR/AHQXLsaBF/3XBBr3Jvuo5ETr+Hs2gw J3yspA7Jdg/wNKuWECX0Z9fL8WM+G81EEPwK/tEvI9j9aZYD4waKCgsQO7GlU1WH CbVNDu4cp/CVcH2vLdxhck7ifhFszXqw55idMJOgIXyJuWKHHvrHvp//TkvbUdh8 4/eOIvWmZt5pm4B5gboamXuNRHtnelxUCqn/svi3KckvU4JXGtDZvPUBONe1bzka w16WD/flJyOwH1r5OxFN+mUrGmvJB4iCgR69USMSWog5UxVG0zcVP6yMqpw90lk= =9/xr -----END PGP SIGNATURE----- _______________________________________________ Messaging mailing list [email protected] https://moderncrypto.org/mailman/listinfo/messaging
