PGP (Pretty Good Privacy) is a cryptography system of the texts based on algorithms with double symmetrical key.

	to read received e-mail: you know for sure that it is sent by the owner of the private key
	to write sending e-mail: you know  for sure that only the owner of the private key can read it.

 

If you are interested you can find other informations here and you will be able to download the program too.

They for the filing of sensitive data on the PC exist many programs and ways of proceed. Kremlin is a coding tool really effective.