Command line encryption

We want to encrypt customer credit card numbers using a strong algorithm when we save them into our database which does not have this option. We want a Windows/DOS command line utility that works something like this: [login to view URL] number key on (encrypt cc number) or [login to view URL] number key off (decrypt cc number) The result would go into the environment variable FPCCNUM ## Deliverables 1) All deliverables will be considered "work made for hire" under U.S. Copyright law. Employer will receive exclusive and complete copyrights to all work purchased. (No 3rd party components unless all copyright ramifications are explained AND AGREED TO by the employer on the site per the worker's Worker Legal Agreement). ## Platform Windows XP and/or Win7 Console DOS