Dear Werner, Thank you for your kind reply.
On 06/01/2014, Werner Koch <w...@gnupg.org> wrote: >>> The question is whether this is really helpful. Yes, it protects your >>> PIN That is helpful. No question about this part! > After a successful verification of the PIN the card allows the use of > the PSO Decrypt command until a power down or a reset operation. I have several questions about this statement. If, after reading them, you believe there exists documentation that should be able to answer them, then please simply point me to that documentation. 1. The document "Functional Specification of the OpenPGP application on ISO Smart Card Operating Systems, Version 2.0.1"[1] mentions "PSO:DEC" but does not define it. That document also mentions "PSO:DECRYPT" but does not define it. And finally, that document defines "PSO: DECIPHER". Are these three terms synonyms, or do they denote different things? 2. I assume that your "PSO Decrypt" means the same as "PSO:Decrypt" in the specification document mentioned above. Is this assumption correct? 3. When you say, "a power down or a reset operation", do you mean (a) "the card is powered down or reset", or (b) "the host computer is powered down or reset", or (c) something else? > Thus > an attacking malware only needs to trick you [into decrypting] an arbitrary > message and is then free to use the smartcard without having the reader > ask you again for a PIN. That is somewhat disappointing to me, although perhaps that is because my knowledge is limited and I am simply unaware of a good reason for this behaviour. Anyhow, am I right in thinking that, having verified the PIN and decrypted a message, disconnecting the reader from the PC (or removing the card from the reader, or both), would cause subsequent malicious attempts to call PSO Decrypt, to result in failure (at least until the card and reader have been reconnected to the host PC and the PIN verified again)? > For the signature key we have this "forcesig" command which switches the > card into a mode which requires a VERIFY command before each PSO Sign > command. I can't find the string "PSO Sign" in [1]. Are you using it synonymously with "PSO: COMPUTE DIGITAL SIGNATURE" (and/or "PSO:CDS")? If not, please can you tell me where the "PSO Sign" command is documented? I can't find the string "forcesig" in [1]. Please can you tell me where it is documented? Many thanks, Sam [1] http://g10code.com/docs/openpgp-card-2.0.pdf _______________________________________________ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users
