-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 On 3/2/15 1:04 AM, Nadim Kobeissi wrote: > We have decided to forego with user-chosen passphrases entirely, > and to stick uniquely to the miniLock model of having a CSPRNG pick > a high-entropy (112-bit) passphrase for users.
Cool! This has always been the SecureDrop model, although the entropy of these passphrases is significantly higher than those of the default length 7-word SecureDrop passphrases (~89.1 bits). We might want to consider increasing the size of our dictionary (fairly small at 6800 words) or the default length of the passphrases; however, doing either introduces usability tradeoffs that must be carefully considered. The unfortunate downside is that to gain this security assurance, you've lost the usability that was theoretically the motivator for allowing users to pick their own passphrases in the first place. Nadim, have you considered adding a feature to Peerio to help train users to remember their long passphrases? Joe Bonneau (who commented extensively on this thread) co-authored a paper [0] recently about using spaced repetition to help people memorize high-entropy passphrases (both more traditional "passwords" and Diceware passphrases). It seems to me Peerio is at an interesting design mid-point between high security and general-purpose usability that might make this an interesting, novel, and potentially very helpful approach. Cheers, Garrett [0] http://www.jbonneau.com/doc/BS14-USENIX-towards_memorizing_random_passwords.pdf -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.22 (Darwin) Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJU+kRiAAoJEEZPConT75yusvQP/3Fd6qyQotr6sq5Eh0D3BC3Y booVH5MI6AcXOpocsc1G69ZEm70RFtY8pUiEbD6pJQU4iITWCQJRE7mqJs6qMV8d InKNK3nAJckI0rJhdVhqWI9xHjTyIyrwY1lykV9R22hZFpqicrPefpjM4xzb73Vm zAQVyMNXuFJB6zxEuQwzGhPuqzdASUZxpNPmzNKar+M2Bmyspdv8jZostm06W9WP Tkcfw/Dfdaq1Bd3nyqt/1kSFJOllNl0PZvf5M1X7M6dZLkRK5nZfnIeIjPENJG3/ B1MFwM3TRtjTc6Y2gIDBpdecDT1ApBWTvHHcGdb5O2qvmbCaBakeYnW/ycIeuVOr TWPj92IDYJ5W4UK+DUcvcnQ5iuTVQ4ZEHVVePPLIjMSH8nIVsr++ij2WbLKKU6lr AtLF4u6kLU4W7Pp7mRS8ngSVl6I+PC7IxDiVQAym8omHq27lHkd7TCM6yrusbSkj M+ihr0tjEqXte4YSACHv5hKpi5wJefhhSY/b024K+z1AY2EBWmodbXFr1Nnkw/+r /8TErxGpnWuf2+5kId9pHBrXK302SFGe9Zcek8KziLfuhvRAh1FT7apVDOkDMS9V 67bqMh/5+kR+a4mgcbPnbgxKTOp5ep6TcQ8dBoXQBOT+gYp5TMkyXgTjdnbQpcM9 gb7nwT0QKMTe+neceQwi =ewTh -----END PGP SIGNATURE----- _______________________________________________ Messaging mailing list [email protected] https://moderncrypto.org/mailman/listinfo/messaging
