encrypting a file
 

i am trying to encrypt a file with cryptsetup, but it doesn't work. what is the code?

cryptsetup is used to encrypt hard drives. cryptsetup is the wrong tool for your needs.

If you want to encrypt a single file it is best to use GnuPG. Here is a nice tutorial for you to read:

http://www.cyberciti.biz/tips/linux-...-password.html