What this means
Valve says that if you pay by credit card, you provide your name, address, card number, expiration date and security code to Valve, which processes it and transmits it to the payment service provider you choose to enable the transaction and perform anti-fraud checks.
Why this matters
Your full card details pass through Valve on their way to the payment company.
What the policy says
If you pay by credit card, you need to provide typical credit card information (name, address, credit card number, expiration date and security code) to Valve, which Valve will process and transmit to the payment service provider of your choice to enable the transaction and perform anti-fraud checks. Likewise, Valve will receive data from your payment service provider for the same reasons.
From Steam Privacy Policy Agreement
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