What's the point of a 'security code' on credit/dbit cards?

[TinyGang]

If you've got the card with the number on it, then you can see the security code too. How does that make the card secur? I don't get it

When you order stuff over the phone or net, you need the code. Hence you need the card. It's to stop a lot of card fraud that comes from people nicking number details from rubbish bins or from the net etc, rather than just nicking the card.

CVV stands for Creditcard Validation (or Verification) Value. Visa, MasterCard, American Express and Discover all have a version of the CVV to reduce merchant risk in Card-Not-Present transactions (like Internet, telephone or mail-order). The CVV code adds assurance that the consumer placing the order has access or physical possession of the credit card itself in order to use the CVV code.

The CVV is a 3 or 4 digit code embossed or imprinted on the reverse side of Visa, MasterCard and Discover cards and on the front of American Express cards. Visa, MasterCard, American Express and Discover have been using the CVV since the late 1990's. The CVV is an important layer of security to help you reduce your risks in accepting card-Not-Present transactions and may be required or recommended by your payment processor or merchant bank.

Extra security device - if the card has been tampered with at an ATM or someone has seen number over your shoulder at till, they can't order stuff via telephone/Internet without the security number.

Oh, I sort of see. But if I pay for something over the phone, and I give the code to the person on the phone, then they have all the details too so they could use it. Or anyone that sees the card for that matter. Wouldn't the security code be more secure if you just had to memorise it, like a PIN number?

But if you give your card details over the phone, surely you're trusting who you're paying? The local curry house or washing machine dealer are unlikely to run up your card as they'll be found out.

also god help us if we had to remember security codes as well as pin numbers..