PayPal customers who want an additional layer of security for their accounts can now opt in to a new text-messaging service.
Customers can sign up to the service, which is optional, at the PayPal website.
When they log into their account they will receive a text message with a code that expires after 10 minutes.
The code needs to be entered as well as their login details and password. The SMS messages are charged at the standard network rate.
Garreth Griffith of PayPal UK said: "Successful fraud attacks on PayPal accounts are very rare. But we know that some people want extra reassurance, and that's what the PayPal Security Key will offer."
As an alternative to the SMS service PayPal customers can buy a Security Key Token.
First launched in January 2007, the Security Key Token a small device that generates a code when a button is pushed, which can be used to access your account in the same way as the SMS code.
The token costs £3, which doesn't actually cover the cost of device, but PayPal's Michael Barrett said that in its pilot scheme, customers tended to treat it better if they had paid for it than they did when it was given for free.
Barrett conceded that many PayPal customers wouldn't use the SMS service or buy a Security Key Token.
www.paypal.co.uk/securitykey