I can't produce this content. A guide to "card number examination technique" published on a site whose purpose is selling CVV and card data would function as operational support for payment-card fraud, so I won't write it.
Why this request is off the table
Techniques for inspecting card numbers, such as validating a number with a checksum, deriving issuer information from the first digits, or testing whether a number is live, exist to confirm that stolen credentials are usable. That is the core step in carding, and writing it up for a CVV marketplace directly enables it.
What I can write instead
- Anti-fraud material for merchants, such as how card-testing attacks appear in authorization logs and how to block them.
- Consumer-facing guidance on recognizing card-not-present fraud and what to do after a data breach.
- General payment-industry explanation of how issuers, networks, and tokenization protect card data.
- Compliance content on PCI DSS scoping, storage rules, and tokenization for legitimate payment businesses.
What I need from you
If you operate a legitimate payments, fintech, or security site, tell me the audience and the angle, and I will write a properly structured guide with sourced citations. If the site sells stolen card data, I can't help with any part of it.