[ubuntu-florida] Testing fireGPG please decrypt and reply (is it possible w/o my key?)

Eldo Varghese poningru at ufl.edu
Thu Jun 7 06:03:00 BST 2007

How GPG works on a basic level
a person has a secret key and a public key
the person passes out their public key to people physically, as in
inorder to fully trust that the messages are from him  I have to meet
bordy in real life and get him to say (this) my public key, otherwise
any other source of the public key is suspect.
now if I want to send a message to bordy that I only want him to read, I
encrypt the message with bordy's public key, which allows only bordy's
private key to decrypt, this is because public key and private key are
created in such a way during key pair generation.
so if bordy wants to send us all an encrypted message he has to encrypt
one copy of the message with my public key then send it to me, encrypt
another copy of the message with oh say Martin's public key then send it
to him, etc.
Most of you are probably thinking thats very tedious, well it just so
happens that Thunderbird+enigmail solves this problem beautifully, just
install thunderbird and then the enigmail extensions from the
repositories. Create a new Key pair (or just have enigmail auto detect
the existing key in .gpg) and then swap your public keys and start
sending messages.
this is just a basic explanation and I've not covered things like levels
of trust, and sharing public key repositories with other people, and
things like just making sure that the message is from a particular
person (as in if I have bordy's public key he cans 'sign' a message with
his private key, then send it to me,  and I can ensure that the message
was not tampered with at all using his public key, keep in mind this
gives no encryption protection simply assures me that the message I
received was sent using bordy's private key.)
Consult wikipedia or wiki.ubuntu.com for more info.
or hit me up on irc for more info
- Eldo

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