how to charge a few credit cards after a period of time?

groupon.com is a great 开发者_开发技巧example when you register they take your credit card information. once a limited amount of people have purchased a coupon a mass amount of credit cards get charged. what is the best method of doing something like this and at the most safest possible way? one thing that i will be doing is encrypting the credit cards in the db with an encryption method that salts the encryption and that i can unencrypted it to use it when needed. would they possibly have a cron that goes through at a period of time to check and see if the coupon time limit has expired then do a mass charge? i cannot wrap around my head to how something can be written that queues transaction charges to a merchant. i am thinking of either using authorize.net or paypal pro.. what do you think from what ive said?

Don't store the credit card information on your server. It would need to follow PCI DSS security standards:

http://en.wikipedia.org/wiki/Payment_Card_Industry_Data_Security_Standard

There's just no reason for it these days. A large percentage of payment processing vendors provide these services for you. You submit the information and receive back a token that can be used to charge the card at a later time.

Furthermore, you are not allowed to store the CVV code.

I personally work with Paypal as the processor, you need to request reference transactions (this will require a background check, probably credit worthiness related and is not guaranteed to be approved). In this way I can authorize a card ($1 authorization only is common and accepted practice) and later charge the card any amount that is appropriate (in our case we have a payment model similar to pay-as-you-go mobile phones). Upon the first charge or authorization I receive a token that I can late use to charge against the "referenced transaction" (essentially just copying the details from the original txn).

Another really interesting option that we looked into was www.paysimple.com, they now have a new API, an attractive pricing structure, and if memory serves, all of the above features.

Many others exist as well that you can and should research. Do watch out though, some card processing providers don't charge anything for the functionality described above (paypal doesn't), but some charge gobs of money for the service. Look, it's generally readily available info on the sites.

Start reading PCI Compliance and periodical payments parts of the source code of an open source cart like Magento. There is a lot to it, if you want to do it all properly.