Published: 2005-11-02

Encryption experts met in Gaithersburg, Maryland, this week to discuss retiring the SHA-1 hashing algorithm and creating a stronger version of the cryptographic workhorse.

Over the past eighteen months, significant breaks of the Secure Hash Algorithm, SHA-1, have left confidence in the crypto algorithm essentially shattered. This week, a Who's Who of encryption experts met to discuss the problem and attempt to chart a course to a stronger hash function. While much of the proposed fixes build on old techniques, some new ideas did come our of the confab, according to a blog of the conference posted by well-known cryptographer Bruce Schneier.

Hash algorithms are mathematical techniques of producing digital fingerprints of files that perform a key function in encryption and digital signatures. A digital fingerprint, or hash, is a small string of numbers that represent a much larger file or document. A digital signature actually validates a document's fingerprint not the document itself, because signing an actual document would be far too processor-intensive.

The threat of a true break in the algorithm is not overwhelming. Cryptographers originally thought that a computer that could perform an attack calculation 1 million times every second would find a collision only once in 38 billion years. In February, the original break found by the researchers consisted of a method that could produce a collision once every 19 million years. A new technique found in August shortened that to once every 300,000 years. There's still some time left.

Posted by: Robert Lemos