Crypto Suggestion/Help

[Paul Rubin]

Jimmy E Touma <jimmyetouma at earthlink.net> writes:
> I need some advise on doing the following. I have a Linux application
> that allows users to access it via a code (password). At the end of the
> day, I gather a log of activities of the users and zip the file and
> would like to encrypt it so that the users can not access it or tamper
> with it. Only manager should. If I use a private/public key for doing so
> I have to store the private key on my computer. What is a good way to
> encrypt a file and have the key well hidden on the same computer? If you
> have any other way to do, like MD5 or similar, please let me know.

Are you saying you have a desktop app that's running on the user's own
machine and you're trying to prevent the user from getting at the log
data?  That is impossible if the user has control over the machine and
is willing and able to hack the software.  If you just want to make an
encrypted file that the user can't decrypt, use a public key on the
user's machine, and only have the secret key on the manager's machine.