You can use:
- GPG – for single files
- TrueCrypt – for entire directories/partitions
TrueCrypt
Home page of this piece of software.
Very easy-to-follow how-to.
The encryption doesn’t use a public key algorithm because the purpose doesn’t require it.
GPG
Basically:
To encrypt myfinancial.info file, type the command:
$ gpg -c myfinancial.info
Output:
Enter passphrase:<YOUR-PASSWORD> Repeat passphrase:<YOUR-PASSWORD>
This will create a myfinancial.info.gpg file.
To decrypt file use gpg command:
$ gpg myfinancial.info.gpg
N.B.: GPG is mostly used for asymmetric key encryption.
