commandliners

For encrypting small text files, I use ccrypt, a nifty utility which uses Rijndael-256 (aka AES-256) and just does it work as it is supposed to do.

$ ccrypt -e my_file

Asks you for a password twice, encrypts my_file (naming the new encrypted file my_file.cpt) and overwrites the old my_file (however, notice that journaling filesystems like ext3 or non-block filesystems might keep some or all the data elsewhere).

$ ccrypt -d my_file.cpt

Asks for the password and, if correct, decrypts my_file.cpt as my_file (and deletes my_file.cpt).

A more useful option for small text files is:

$ ccrypt -c my_file.cpt

which, after asking for the password, sends the unencrypted data to stdout (cats it, so to say).