> On 2015-11-15, at 21:07, Uwe Brauer wrote: > That came out wrong, then. Part of my problem would be to figure > out the “real” e-mail address of “Ed Snowden”. If you registered > the fresh e-mail address “[email protected]” and uploaded a > matching key to usual keyservers, then I might fall for that. No > special attack skills required.
Correct but this applies to smime and gpg. > I don’t know too much about CAs that issue e-mail certificates for > free. However, based on your description of Comodo I guess that you > could also obtain an S/MIME certificate in the above case (for > [email protected] after registering that address). So the > “trust” built into S/MIME seems worthless. For class 1 certificate yes, for class 2 not, there you have to show up (and to pay.) > For me as malicious CA (or intruder into a CA) there is no reason to > steal the private key as I could generate a certificate with > matching private key in your name for your e-mail address, which is > “trusted”. Then I could send signed e-mails in your name. That > alone might get you into trouble, but you might receive responses > that alert you about some ongoing attack. If I was a powerful > attacker, able to replace e-mails on the way, I could additionally > re-encrypt (modified) responses to your real certificate (or drop > messages entirely), and you would never know I was there. > If I cannot replace e-mails on the way, I can still send “trusted” > signed e-mails in your name and tell the recipients to switch to > different e-mail addresses with “trusted” certificates. Then, > again, I can re-encrypt responses to your real certificate and > e-mail address. But in all of these scenarios you need to hack the email account. It is not sufficent just to use a linux smptmail server and manipulate the form field. You also have to intercept the reply. I don't see much of a difference between - the pgp scenario: to place a falsified pgp key on a server - the smime scenario: to crack a smime certificate by breaching a CA (which is more difficult that placing a falsified pgp key). Best Uwe Again the question was is smime easier to use. _______________________________________________ info-gnus-english mailing list [email protected] https://lists.gnu.org/mailman/listinfo/info-gnus-english
