GNU Privacy Guard for dummies
To Generate a keypair in Gnupg, the command that you have to write in the linux terminal is:
This is the output of the command.
gpg (GnuPG) 0.9.4; Copyright (C) 1999 Free Software Foundation, Inc.
This program comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it
under certain conditions. See the file COPYING for details.
Please select what kind of key you want:
(1) DSA and ElGamal (default)
(2) DSA (sign only)
(4) ElGamal (sign and encrypt)
for this tutorial im going to select the "DSA and ElGamal" type of key.
DSA keys have a minimum length of 1024 and a maximum lenght of 3072 bit.
What keysize do you want? (2048)
For this example i am going to use the default settings, which is 2048bits of length.
Then GPG will asks how long our key should last before expiring
now, i will put in 0, as it is the default setting, and it is handy for this guide.
Please specify how long the key should be valid.
0 = key does not expire
(n) = key expires in n days
(n) w = key expires in n weeks
(n) m = key expires in n months
(n) y = key expires in n years
Key is valid for? (0)
Next thing GPG will ask, is our name and email address
GnuPG needs to construct a user ID to identify your key.
then after i input my name, and press enter we need to input our email address
and, then press O to confirm the data that you have given in input to gpg
You selected this USER-ID:
Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit?
After this, a popup window will open, prompting you for a passphrase, please make sure to remember it
Congratulations! you have succefully created your first keypair!
Exporting our key and crypting a document
Now, we need to export our public key to a gpg file.
gpg --output nKey.gpg --export emailChiave
replace emailKey with the email you put in at the start, this command will export the key in a file named nKey.gpg, be free to name it another way.
now, send the key to another computer, using whatever medium you prefer, it can be either a storage medium, or an email service ecc...
gpg --import nKey.gpg
then, on the computer you sent the key to, write this command to import your public key
now we will finally encrypt a file with our public key
gpg --output nameOfTheCryptedDocument.gpg --encrypt --recipient emailKey nameOfTheDocument
you did it! now send the encrypted document back to your first computer
gpg --output document --decrypt nameOfTheCryptedDcomument.gpg
with this command, after writing your passphrase, the document will finally be readable again.