Google Shrinks Chrome Updates With 'Courgette'

Part of Google's security strategy for Chrome involves the use of 'silent updates,' browser patches downloaded without specific authorization by the user. It's a controversial practice because spyware and malware also download files without the express consent of users.But Google has studied the issue and found that silent updates produce the best results. Though one should be skeptical of any study backed by a company that presents the company's products or actions in a positive light, one should also acknowledge the obvious: When you leave update decisions to people, not everyone will choose to update. And the consequence of not updating one's browser may mean being "owned" by a hacker and having one's computer become part of a botnet that menaces others.

On Wednesday, Google said that it was improving its silent update process by introducing a new compression algorithm called Courgette, the term used in Britain for zucchini. Feel free to decide whether there's some hidden significance in this chosen name.

Google had been using a compression utility called "bsdiff," which generates the difference between two files so that the original file can be updated with only the changed information. But the company wasn't happy with the size of the files produced. So its engineers created a new algorithm to make the patch files even smaller and thereby improve the silent update process in Chrome.

Courgette's results are pretty impressive: a bsdiff update that weighed in at 704,512 bytes was 78,848 bytes when processed by Courgette.

With smaller updates, less bandwidth is used and the user's computing experience isn't affected as much.

"The small size in combination with Google Chrome's silent update means we can update as often as necessary to keep users safe," said software engineer Stephen Adams in a blog post.

Google has posted a summary of Courgette and plans to publish a more detailed academic paper at a later date.