We use cipher5.fll, works with all versions of VFP, never had any problems so far.

You encrypt the data before writing to the table, like:

lnTest = "Hello World"
replace table1.field1 with encrypt(lnTest, YourKey)

The same call encrypts/decrypts, so reading is Store encrypt(table1.field1, YourKey) to lnTest

If a user tries to read the VFP data outside of your app, it is all encrypted.

If you want to go 1 step further and prevent them even seeing the encrypted data, add an audit trail like FoxAudit. The only way to see the data is if FoxAudit successfully instantiates itself, which would be very difficult outside of the VFP environment. Password protect the FoxAudit startup, and only the most determined hacker has a chance.