Enigmail
After some time hesitating i have installed enigmail in Thunderbird. As i'm just a beginner i added my public key (PK) to a keyserver. I was now wondering about the fact that if a 3th party intercepts a mail from me to a friend, is that 3th party able to read the mail considering they can get my public key from the keyserver. Because that's the way i got the PK of my friends e-mailadress. I did not yet figure out how to send an (encrypted) mail to someone with my PK added to it as attachment.
Some thoughts ?
Well, i really did that, but i figured out that Layout of TB and Enigmail was differend in Win7, Ubuntu and Trisquel. I have read the manual.
I haven't really looked into it, but from what I can tell, the public key can only be used to encrypt, not unencrypt. To unencrypt a PGP-encrypted file, you need the private key. So you use someone else's public PGP key to encrypt e-mails you send to them, and then only they can read that e-mail, unless they make the mistake of sharing their private PGP key with others.
Someone more knowledgeable about PGP can correct me if I'm mistaken.
To authenticate a message, one uses her private key (to encode a hash of the message; the proper message is in clear). The recipient use the public key to check that the sender of the message really is who he pretends to be. With the sole public key, nobody can usurp the identity.
To encrypt a message, one uses the public key of the recipient (the message is *not* in clear). The recipient uses her own private key to decrypt the message. With the sole public key, nobody can read the message.
To both authenticate and encrypt a message, one uses both her own private key and the public key of the recipient (the message is *not* in clear). The recipient uses the public key of the sender to check her identity and her own private key to decrypt the message. With the public keys, an attacker cannot do anything.
All in all, it is normal that the public key is, well... public!
On 04/11/13 05:39, chris.arijs wrote:
> After some time hesitating i have installed enigmail in Thunderbird.
> As i'm just a beginner i added my public key (PK) to a keyserver. I
> was now wondering about the fact that if a 3th party intercepts a
> mail from me to a friend, is that 3th party able to read the mail
> considering they can get my public key from the keyserver.
onpon4 is correct, a public key can only be used to encrypt messages for
you and verify signatures created by you. A lot of people get confused
by the fact that you don't need your own key to encrypt a message for
your friend, you use your friend's public key.
Keyservers are useful for publishing a public key to the world, so
anyone can send you encrypted mail. Keep in mind that they can
theoretically be MITM'd, but in practice this is pretty rare.
Andrew.