Data protected on unlocked Web sites

Looking up information on the Internet is easy, but is it sometimes too good to be true? How do you know that a posted investment history, for instance, is correct and complete?

Existing technology allows an author to use a digital signature to authenticate a document. The author signs the document using a private key program, which performs a mathematical calculation on the document. To view the signature, the reader downloads the authors public key, which can be posted in a publicly available place.

But existing signature schemes only work with specific sets of data. To request the last two years of that investment history, for example, you might have to download the entire record to get an authenticated copy.

A team of researchers has come up with a signature scheme that allows portions of signed documents that are stored in Extensible Markup Language (XML) databases to be retrieved and authenticated. "The existing XML signature standard won't let you do that. You can only authenticate an entire document, not parts of it," said Premkumar Devanbu, ... // 83% Remaining