
\S encrypt:  decrypt \S

You encrypt a file when you want to keep its contents secret.  To encrypt a
file, you specify a key or password that transforms the contents so that it
is unintelligible and difficult to decode.  If the file contains encrypted
information, then the key or password decrypts the information and returns
it to its original form.  You can encrypt a file using the UNIX system
command crypt(1).

