Some crypto apps let users inspect the public-key hash (aka "fingerprint") of the other party, so that it can be compared with a value received through a different channel (phone call, business card, online directory or website, etc.)
There's a lot of variation in how public-key fingerprints are presented (alphabet, number of chars, capitalization, grouping, separators, etc). For example: SSH: 43:51:43:a1:b5:fc:8b:b7:0a:3a:a9:b1:0f:66:73:a8 GPG: 7213 5CAA EA6B 0980 126A 0371 8373 DD15 4D42 48BD OTR: C4E40F71 A92175F8 597A29A7 CB7E0943 B27014FF TACK: g5p5x.ov4vi.dgsjv.wxctt.c5iul Bitcoin: 31uEbMgunupShBVTewXjtqbBv5MndwfXhb SSH: 128 bits, 32 hex chars GPG: 160 bits, 40 hex chars OTR: 160 bits, 40 hex chars TACK: 125 bits, 25 base32 chars (RFC 4648) Bitcoin: 200 bits, 34 base58 chars (160 bits hash + version/checksum) There's also some fingerprint innovations that aren't widespread: - Zooko's z-base32 - "Hash extension" from RFC 3972 to squeeze more bits into a smaller fingerprint - Phonetic alphabets like the PGPfone wordlist Anyways, these are somewhat large strings for users to handle, so it seems worth trying to streamline the experience and reduce error-rates due to soundalike or lookalike characters as much as we can. I'm a little surprised I can't find more useability research here, except for: - https://blog.crypto.cat/2014/01/cryptocat-at-the-openitp-dc-hackathon - https://moderncrypto.org/mail-archive/curves/2014/000011.html Are there other studies? Are there any "best practices" emerging? Trevor _______________________________________________ Messaging mailing list [email protected] https://moderncrypto.org/mailman/listinfo/messaging
