-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 24/03/14 09:57, Daniel Thomas wrote: >> Identicons are a catastrophe for cryptographic use - there's no >> way an average person can distinguish more than 2^20 different >> polygonal pictures. Given one picture, it's not hard to make a >> key whose fingerprint has the roughly the same polygons and >> colours. Do not use!
Depending on the use case, it may be possible to work around this limitation by including a private salt (known only to the verifier) in the hash. An attacker trying to match a given identicon would then have to guess at random, without knowing how close their match was for any given verifier, and without being able to find a good match for all verifiers at once. The downside, of course, is that each verifier would see a different identicon for a given identity - it wouldn't be possible to print identicons on business cards etc. I guess this is analogous to the difference between fingerprints and short authentication strings. Cheers, Michael -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQEcBAEBCAAGBQJTNrh7AAoJEBEET9GfxSfMsFUIAL1fY/0CrqudggZOeIQgg9F/ bQkED2dTNLxhzYyO/MZ0fyT5MWDjflruJ4xuu74kYcsD75n70ibPfNIgPMNUNTYQ OcnkVqA59fMYZSqa7Oo75wRQ46kULpDaezH4B+QY3G71ePBUEWqqZ4L4/fx9o3L9 7eUE3SfzCHKzjoEXhG8ZvlHGVLnbXqJdbmSaxUYaYbQ4zIJekSjLJoOWWWCSR2VN IsqWkVdtj+1AFjUVHXyfV7dcwpAGPIeKBZhzD3VfWOwnxNKsx9kJWl9mze37UpRJ HN8alfnsWk5igwdgfo9CS9d/HNGJL3euokKwDlaZqH2EO0zMhcS+lPChDsXwoA0= =BDc5 -----END PGP SIGNATURE----- _______________________________________________ Messaging mailing list [email protected] https://moderncrypto.org/mailman/listinfo/messaging
