The Secure Sockets Layer Protocol
The data that is sent between web servers and browsers can be protected using the encryption services of the Secure Sockets Layer protocol, SSL. The SSL protocol addresses three goals:
- Privacy
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The content of a message transmitted over the Internet can't be understood by a casual (or determined) observer.
- Integrity
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The contents of a message received are correct and has not been tampered with.
- Authentication
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Both the sender and receiver of a message can be sure of each other's identity.
SSL was originally developed by Netscape, and there are two versions: SSL v2.0 and SSL v3.0. We don't detail the differences here, but Version 3.0 supports more security features than 2.0. The SSL protocol isn't a standard as such, and the Transport Layer Security 1.0 (TLS) protocol has been proposed by the Internet Engineering Task Force (IETF) as an SSL v3.0 replacement.