Security is probably one of the most significant concerns for both the consumer and the retailer during an on-line transaction. In reality an on-line transaction is probably more secure than a card transaction in a shop or conducted over the telephone or by fax. Information transmitted on-line is encrypted using complicated logarithm combinations, unlike these other methods that use standard medium coding. The WorldPay Select payment gateway uses a combination of both established and innovative techniques to ensure the security and integrity of all sensitive data, protecting both the retailers and their shoppers. All communication between the shopper and WorldPay is encrypted to the maximum strength supported by the shopper's browser using TLS or SSL (security). Our public web servers are certified by Thwate, a public Certificate Authority, ensuring that shoppers and retailers alike can have confidence that nobody can impersonate WorldPay to obtain confidential information. All communication between the retailer and WorldPay, including the details of the purchase, are encapsulated using our own encrypted and digitally-signed protocol; this uses a combination of standard methods such as PGP, RSA and MD5 to ensure that the information passed is secure and tamper proof. Data storage on WorldPay systems, and the communication between WorldPay and the worldwide banking networks, is regularly audited by the banks themselves. We ensure that we stay up-to-date with the latest versions of any third-party code we use, and continually review our own proprietary code, using current best practice at all times. The cardholder is further protected: Card issuers protect cardholders from fraudulent use of their card in a "card not present" environment, such as over the internet or telephone. As the shopper did not sign for the goods, they have the absolute right to demand a chargeback if those goods did not arrive or the card was used fraudulently.