On 28-02-2015 18:56, Christoph Anton Mitterer wrote: > I'm not sure but I fear you have some deep misunderstanding of > cryptography...
I'm not talking about mathematically proving something. After all, a government agency could make a false key with Werner Koch's name on it and send someone who looks like him with real ID documents to a keysigning party. Government-issued ID's are no mathematical proof either. > "Well-known", "often seen enough" or "not having heard any noise about > it" are absolutely no ways to prove the validity of a key's named > identity. No proof no - but nathematical proof does not exist in this matter. > If there was only one "Werner Koch" on the keyservers, and that key was > signed by thousands of other famous names (Linus Torvalds, and that > like) you still couldn't be sure of anything. Of course not, anyone can upload a key with any name to the keyservers. But I doubt anyone can publish a fake key on www.gnupg.org without anyone noticing for long. > An attacker that MitMs you could just set up a fake web-of-trust in very > little time and when you ask your favourite keyserver, block any of the > "real answers" and instead deliver you his faked key space with all the > mutual signatures and so on. I am not talking about keyservers at all, except maybe for obtaining a key with a given keyID. Nothing more, and no WoT issues. While I understand the concept I consider the WoT way to complicated and I use it only as additional evidence a key belongs to someone. > And you'd think "Only one Werner Koch, with an @gnupg.org email, even > signed by all these other people - that can't be coincidence, some of > the must have checked his ID, and if it was an impostor, I'd surely have > read on heise.de about it" - while in fact no one else than you ever saw > these faked keys. If the key was only on the keyservers, sure, then even I could do that myself easily. But I'm talking about keys on places where it is unlikely anyone has write access to, like the gnupg website or as a signature in mailinglist messages. Sure, it could be spoofed - but only a short time before it get noticed. It would not be the first time I read about a spoofed gpg key on a Linux distro server when the server was hacked. The attack works - but not for long. -- ir. J.C.A. Wevers PGP/GPG public keys at http://www.xs4all.nl/~johanw/pgpkeys.html _______________________________________________ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users