All transaction information passed between our website and the SagePay Payment System is encrypted using 128-but SSL certificates. No cardholder information is ever passed unencrypted and all messages from SagePay are signed using MD5 hashing to prevent tampering. You can be completely secure in the knowledge that nothing passed to SagePay can be examined, used or modified, by any third-parties attempting to gain access to sensitive information.
Once one the SagePay system, all data is secured using internationally recognised 256-bit encryption standard used by many organisations, including the US Government. The encryption keys are held on state-of-the-art, tamper proof systems in the same family as those used to secure VeriSign's Global Root certificate, making them all but impossible to extract. The data they hold is extremely secure and they are regularly audited by the banks and authorities to ensure it remains so.
SagePay also has multiple private links into the banking network that are completely separate from the rest of the Internet and do not cross any publicly accessible networks. Any cardholder information sent to the banks and any authorisation message coming back is secure and cannot be tampered with.
No individuals within our company or SagePay are able to decrypt transaction or cardholder details. Their systems only allow access to our most senior staff and only in extenuating circumstances (such as investigations of Card Fraud by the Police). Your card information is secure even from their own employees because the systems never display the full card numbers, even on administration screens.