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Chrome a bit less secret as PDF reader goes open-source

The software Google's browser uses to show PDF files has been proprietary for years, but now it's an open-source project called PDFium that others can scrutinize or use themselves.

Stephen Shankland/CNET

Chrome, Google's mostly open-source Web browser, just got a little less proprietary.

Foxit's software for reading PDF (Portable Document Format) files, for years a proprietary part of Chrome, now is an open-source software called PDFium, Foxit announced on its blog. Google's François Beaufort pointed out the change on Google+ Wednesday. The change means there's one more useful tool that programmers can draw upon and one less piece of potentially suspicious software that Google critics can fret is lurking in Google's browser.

With open-source software, anyone may scrutinize and modify the underlying source code then distribute the finished software products built from that source code. The approach shuts off the obvious money-making opportunities of proprietary software such as Microsoft Word or Adobe Photoshop, but it can be good for security since more people can track down bugs and vulnerabilities. It also helps build a community of interested people and organizations that collectively develop the software and can rapidly encouraging the spread of the open-source software since it's available at no cost.

Security is a particularly important consideration in the case of PDFium: PDF software has been a high-profile way for people to launch attacks on Web browsers. By making PDFs easier for programmers to support, the PDFium move also could help the prospects of PDF, a file format standard originally created by Adobe Systems that's widely used today for archival data like bank statements and carefully formatted documents like online brochures.

It's common to see open-source software sponsored by companies that use it to serve a different end than direct sales. In Google's case, those ends are online services such as search, Gmail, YouTube, and Google Apps. Google doesn't sell Chrome, but Chrome furthers Google's money-making services.

One company's open-source project can also undermine the business prospects of another company's proprietary rival -- Google's open-source Android mobile operating system taking on Apple's proprietary iOS, for example. In the case of the open-source PDFium, Adobe Systems for years has given away its Adobe Reader software for viewing PDF files at no charge to users, but its higher-end Adobe Acrobat tool -- which can create and edit PDF files -- costs money.

Google runs another open-source project called Chromium that, when combined with some proprietary elements, becomes Chrome. Chrome has grown over the last year to become the second most used desktop Web browser behind Microsoft's Internet Explorer. Among Chrome's proprietary parts are software for decoding video compressed with the patent-encumbered H.264 technology, a version of Adobe Systems' Flash Player, and Google's own Widevine digital rights management (DRM) software for video copy protection. Now, the PDF reader is no longer on that proprietary list.

That's good news for Google and others, too, according to Peter Kasting, a founding member of the Chrome team.

"It reduces the number of closed pieces of Chrome, and thus the surface area for which people can be suspicious that we're doing something shady. It makes a high-quality PDF plugin available to users who only want an open-source product and were using Chromium as a result," Kasting said. "It is almost certainly the highest-quality PDF engine available in the open-source world, and can now serve as a reference for other projects, or be included in other browsers based on Chromium or other open-source projects entirely."

Google has enough power, exerted through search, Android, Chrome, and other avenues, that it attracts many critics. The transparency of open-source software makes it harder to hide something nefarious within a program, such as a service that secretly shares private data with a government surveillance operation.

One of the beneficiaries of the PDFium move is Opera Software, which scrapped its own browser engine last year and incorporated that of Chromium instead. Now it'll get a PDF reader of its own for free.

Mozilla has taken a different approach with its Firefox browser. It's build its own PDF reader called PDF.js that runs atop the browser engine itself using the JavaScript language. It's already open-source software, like just about everything Mozilla does.

Foxit, too, is of course affected by the open-source move.

"Our high-performance, highly accurate, and platform-independent software technology will help developers everywhere to incorporate powerful PDF technology when creating innovative applications," said company Founder and Chairman Eugene Xiong in the company's blog post. But it's not stopping sales of its product: the company still charges for use of its Foxit PDF SDK (Software Development Kit), which can be embedded in other software and which offers more features than the open-source PDFium.