How do I validate a credit card number in ASP?
While with ASP alone you can't verify that a credit card belongs to this person, that it isn't stolen, that the credit is good or that the purchase price doesn't exceed the card's limit -- you can verify that it is a possible number (using a rough translation of Luhn / checksum) before bothering to waste transaction time with a true verification authority.
Most hosts will have credit card acceptance already set up for you. However, if you're doing it yourself, you're going to need a little bit more than a Luhn validation function. You will need an SSL certificate from Thawte or Verisign. For various reasons, I recommend Thawte. You will also need a secure place to store customer information. Keep in mind that you should try to avoid storing credit credit information if possible; the potential liability here is enormous. If you're going to store this information, you better have a well-guarded fort, and consider encrypting the number (see Article #2249 and Article #2397).
You can look at these other vendors for credit card processing, either in component form or as a real-time service:
You can also see some of the shopping cart products listed in Article #2225. (Depending on capabilities, some vendors might be listed in both articles.)
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