QUERY: S/Keyish PGP?
-----BEGIN PGP SIGNED MESSAGE----- A quick question: Has anybody considered the possibility of hacking something into PGP's password protection to allow an S/Key like access? IE, I'm sitting here in FL on a 2400 bps modem, telnetted through Netcom's dialup to hks.net, so I'm not bloody likely to be typing my passphrase in and thus am barred from using PGP (without hideous contortions, that is). My questions: - Has anybody done any work on making an S/Key-like mechanism with the assumption that the machine running PGP is (somewhat) secure? This I'm certain is technically possible. More complex: - Has anybody put any thought into a mechanism based upon one-time passwords for regulating PGP private key use on shared, insecure machines (strength == quality of password, of course)? If people could have a widget very much like the Macintosh S/Key widget on their Mac fom which they could cut-n-paste their one time password, it seems like we'd be one step closer to addressing concerns like Tim's. Just a thought... A GUCAPI would make such a mechanism easier, of course (I haven't abandoned the GUCAPI thought: I'm just gestating). - --- [This message has been signed by an auto-signing service. A valid signature means only that it has been received at the address corresponding to the signature and forwarded.] -----BEGIN PGP SIGNATURE----- Version: 2.6.2 Comment: Gratis auto-signing service iQBFAwUBLvOEUSoZzwIn1bdtAQGRSgF8DAt6/1WjmiU3clMy0E+EU4RDmcF0JaGC Y+pNb8dgOzWXEr9b5EyWM0BS4uqw13mK =Xsa9 -----END PGP SIGNATURE-----
| A quick question: Has anybody considered the possibility of hacking | something into PGP's password protection to allow an S/Key like access? I thought of this, bounced it off a few people, none of whom caught the flaw. When I got around to implementing it, I realized that for it to work, your key would have to be securely stored on your unix box without encryption. The way S/key works is it uses your ability to provide the input to a one way function whose expected output S/key knows. There is no secret data stored on the server. In contrast, PGP needs secret data which it uses to encrypt your key while it is stored. Offhand, I doubt it can be done without storing your key in the clear, or trusting the local CPU. If you can store your key in the clear because you feel the comprimise of your key is an acceptable risk, you are all set. Similarly, if you trust the local CPU, you can probably do an encrypted telnet or somesuch. Don't take that to mean it can't be done; I'm not even an amateur cryptographer, and there may well be some clever way of doing this that I haven't thought of. Adam -- "It is seldom that liberty of any kind is lost all at once." -Hume
participants (2)
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Adam Shostack -
cactus＠seabsd.hks.net