McAfee 5 manual How does encryption work?, McAfee Internet Security

Internet Security and Privacy

Certificates are Microsoft technologies designed to guarantee a person’s identity and Web site security. Personal certificates verify that you are who you claim to be. Web site certificates verify that a Web site is secure and what it claims to be (so Web sites can’t falsify their identity). When you open a Web site that has a certificate, Internet Explorer checks if the certificate is correct. If the certificate is not OK, Internet Explorer warns you. Certificates are great, in theory. The problem is that they only establish a security standard—Web sites are free to choose to use certificates, or not.

How does encryption work?

The only way to keep a secret is if you do not tell anyone, and if you do not jot it down. If you need to share the secret, you can hide it within another message, and let the intended recipient know how to find it. Computer encryption hides messages by making the original data unintelligible. The intent is to garble the data so that it can not be read. In this case, the data it self is useless if access by an unintended recipient.

The simplest encryption systems use letter shifting, in which a message is encrypted by shifting every letter n letters later in the alphabet. For example, say A is changed to B, and B to C, etc. As long as the recipient knows how you shifted the letters, they can easily decrypt the message by reversing the process. Of course, a brute force approach to breaking this sort of encryption would simply try all possible 26-letter combinations until the final message was retrieved—not a very strong method of encryption.

Computer encryption uses a much more difficult technique of hiding the message. Rather than a simple letter-shifting scheme, the original message is transformed by a mathematical algorithm. The algorithm uses a secret “key” to scramble the message, and the key is necessary to unscramble it. The key is similar to a house key: The more teeth a key has, the more difficult it is to pick the lock. Similarly, “strong” encryption uses keys with many “teeth”—in this case, bits of data.

There are two commonly used levels of encryption. The international standard is 40-bit encryption, but some sites in the United States use a higher level of 128-bit encryption. The number of bits indicates the length of the key used to encrypt data. The longer the key, the stronger and more secure the encryption.

On the Web, your browser works with secure Web sites to establish and manage the encryption that secures information. If your browser security options include the Secure Sockets Layer (SSL), which ensures data transmission privacy, you should turn on this option to facilitate secure data transmission.

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McAfee Internet Security’s Security Check automatically checks your browser’s security level, and lets you know if you need to change it.

104 McAfee Internet Security 5.0