Encryption & digital signatures

[Don Coleman]

A Pharmacy client of mine has begun to include a diskette (I know, I 
know, starting out low-tech) of prescription order information with 
their daily order for several customers.  Their customer will then 
import the data into a small fP app. that I wrote and will receive in 
their orders via bar-code scanner and reconcile the items they receive 
with the what the pharmacy shows they shipped to the customer.  This 
diskette currently contains patient names and numbers which should 
probably be encrypted and digitally signed to alleviate HIPPA and JCAHO 
patient privacy and confidentiality concerns.  Can anyone make any 
recommendations concerning methods to encrypt and digitally sign the 
data file here at my client site and then reverse (un-encrypt) the 
process at their client site?  My client's hardware is Windows 2000 
Advanced Server with WIN2000 and WIN XP PRO clients.  Their clients are 
using fP single user native versions on either WIN98, WIN2000, and WIN 
XP clients.  All suggestions appreciated.

Don Coleman