Payment card data is the information used to authorize or process a card payment. It usually includes the card number, expiry date, cardholder name, and sometimes the security code or other verification data. In practice, this is the data an online merchant, payment processor, or attacker can use to attempt a purchase.
It matters because card data is directly monetizable: if criminals collect it, they may try fraud, account takeover, or resale on underground markets. Attackers often steal it through phishing, smishing, fake checkout pages, malware, or data breaches. Defenders protect it with strong payment-page validation, tokenization, encryption, fraud monitoring, and user checks that reduce trust in unexpected links or forms, especially in SMS messages.