I think you need to do some carefull thought anbout this and what you are trying to achieve
storing credit card inforamtuon in clear in a db, especailly MS Access / JET is not a smart idea.
depending on where you are based there may well be leagl implications, not just db implications. ferinstance the UK has the data protection act, and doing what you propose may fall foul of that.
OK granted you can circumvent the DPA and its siblings by storing the information in a (paper) file nearby to the computer.
I think you need to read up on security in the Access world (there is a FAQ on Access security on t'web). read it, read it again, read it once more, take a back up each time you try to apply changes.
tie down youyr db using user accounts and passwords. then test those assumptions that the b is secure vbyt5 tryin to connect to the data from another tool.
security also varies with which versions of JET you use, new versions of Access use a different security model.
look athe Microsoft encryption libray, forget what its called, but that may well work for encrypotion for you. whatr you probably need is to encrypt the card number and the ***2 number, then retieve that inforamtion using the correct decryption key.
bear in mind what you have is valuable information, you are not just protecting your own custoemrs data, you are demonstrating to your auditor or the police or whoiever that in the event of a problem (an employee, theft of equipment, disposal of old equipment) and so on that you have taken the 'right' steps.
I'd rather be riding on the Tiger 800 or the Norton