PGP encryption uses a serial combination of hashing, data compression, symmetric-key cryptography and finally public-key cryptography; each step uses one of several supported algorithms. Each public key is bound to a user name and/or an e-mail address. A detailed example is here.
Also, you can encrypt files using a custom password, without a public key.
Install GnuPg tool:
emerge pv app-crypt/gnupg
apt-get install gnupg
I want to crypt my_work.zip file:
gpg2 -c my_work.zip
enter twice the password.
The result is a new encrypted my_work.zip.gpg
tmp # ls -l my_work.zip my_work.zip.gpg
Delete “my_work.zip”, do not forget this step if you wish to keep your work only in a encrypted file.
To get back your original file, issue this command:
tmp # gpg2 my_work.zip.gpg gpg: keyring `/root/.gnupg/secring.gpg' created gpg: CAST5 encrypted data gpg: encrypted with 1 passphrase gpg: WARNING: message was not integrity protected
It ask for password!
….wait….and now you have again “my_work.zip” file!