Credit Point Web application

I have started working on a e-commerce website. This website will run PHP and MySQL and requires to have a credit system for the users; they will be able to pay with the credit, top it up by vouchers or regular payment, as well as withdraw.

Now I do have experience with credit cards processing APIs, so paying money in and out shouldn't be a problem; what however is a problem is how to securely store the credit information. Storing it as a single numeric field is not exactly ideal and potentially could be exposed fairly easily. What I was thinking is keep all the transactions and credit history of each user in a separate table, and every time they log in recalculate what should their credit be. Same would then apply开发者_如何学Python before any transaction that they attempt to do. I would like to hear what are your thoughts how this should be implemented.

EDIT: Just to clarify; my question is not on how to process credit cards and won't be storing credit card information. I will use a well known and secure API to process the payments (e.g. via paypal). However based on the credit card payments, I need to attribute the appropriate user points in a form of credit. These points would be a representation of funds on the website (whilst the money would be retained on the company account, until the user tried to make a payment/withdrawl) and would be used to make payments and withdraw funds. Again for the actual payment processing I would use secure API, however I am not sure how to implement the credit points properly from structural point of view in the application itself. I don't want to use a simple one field point system, as that I would consider very dangerous. I hope that clears it up a bit.

Cheers

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This might not be the answer you are looking for but here are my 2 cents.

In my personal opinion unless you have someone monitoring your dedicated servers 24/7 you should never in any format store credit card numbers in your database, it is just too risky.

A very nice solution I came across last year was BrainTree http://www.braintreepayments.com/. You can set up a very nice credit card payment system without taking on any liability yourself. Their API allows server to server and transparent redirect (form posts to their site and they redirect back to your site) transactions. At the same time their Vault service allows you to store credit cards on their end and you just use a token in the server to server API to process a payment. You can store the last 4 digits (which they provide in the transaction detail) in your DB along with the CC type and the token, with this you can display a drop down for the user to select which card they want to use and you just use the token when talking to their API.

The API is very nicely documented with full examples. I think you should look into them.

Edit: I believe you should have a table as you have suggested to store all the history and 'totals' field in the users table, which can be used to display in various places. Each time a transaction a made calculate the total and cache it in this field for ready usage. However it is a good idea to re-calculate this in certain crucial places to make sure everything is in order. Even though this field is exposed but you have a full log which can help you re-calculate everything if needed.