{"id":18540,"date":"2022-03-10T10:30:59","date_gmt":"2022-03-10T18:30:59","guid":{"rendered":"https:\/\/engineering.fb.com\/?p=18540"},"modified":"2023-06-29T15:12:09","modified_gmt":"2023-06-29T22:12:09","slug":"code-verify","status":"publish","type":"post","link":"https:\/\/engineering.fb.com\/2022\/03\/10\/security\/code-verify\/","title":{"rendered":"Code Verify: An open source browser extension for verifying code authenticity on the web"},"content":{"rendered":"

Update on June 16, 2023 at 10:30AM PT:<\/strong><\/span><\/p>\n

Today we\u2019re announcing the introduction of Code Verify for Instagram Web. The Instagram Code Verify extension is <\/span>offered by<\/span> Meta Open Source<\/span><\/a> and is available on the official browser extension stores for <\/span>Google Chrome<\/span><\/a>, <\/span>Microsoft Edge<\/span><\/a>, and<\/span> Mozilla Firefox<\/span><\/a>. <\/span>With Code Verify, you can confirm that your Instagram Web code hasn\u2019t been tampered with or altered, and that your Instagram Web experience is the same as everyone else\u2019s. <\/span><\/p>\n

Update on August 11, 2022 at 10:30AM PT:<\/strong><\/span><\/p>\n

Following our introduction of Code Verify for WhatsApp Web, today we\u2019re announcing the introduction of Code Verify for Messenger. The Messenger Code Verify extension is offered by <\/span><\/i>Meta Open Source<\/span><\/i><\/a> and is available on the official browser extension stores for Google Chrome<\/a>, Microsoft Edge<\/a>, and Mozilla Firefox<\/a>. As with WhatsApp, using <\/span><\/i>Code Verify enables you to confirm that your Messenger Web code hasn\u2019t been tampered with or altered, and that the Messenger Web experience you\u2019re getting is the same as everyone else\u2019s.\u00a0<\/span><\/i><\/p>\n

Originally published on March 10, 2022 at 09:00AM PT:<\/strong><\/span><\/p>\n

Since WhatsApp introduced<\/span> multi-device capability<\/span><\/a> last year, we\u2019ve seen an increase in people accessing WhatsApp directly through their web browser via WhatsApp Web. With this shift in mind, we\u2019ve been looking at ways to add additional layers of security to the WhatsApp Web experience. Starting today, you can now use Code Verify, an open source web browser extension that automatically verifies the authenticity of the WhatsApp Web code being served to your browser. Code Verify confirms that your WhatsApp Web code hasn\u2019t been tampered with or altered, and that the WhatsApp Web experience you\u2019re getting is the same as everyone else\u2019s.\u00a0<\/span><\/p>\n

For years, WhatsApp has protected the personal messages you send on WhatsApp Web with end-to-end encryption as they transit from sender to recipient. But security conscious users need to be confident that when WhatsApp Web receives these encrypted messages, it is protected as well. In contrast to a downloadable mobile app, a web app is usually served directly to users, without a third party reviewing and auditing the code. There are many factors that could weaken the security of a web browser that don\u2019t exist in the mobile app space, such as browser extensions. Additionally, because the mobile app space was built after the web was created, the security guarantees offered on mobile can be stronger, particularly given that third-party app stores review and approve each app and software update. But today, that\u2019s changing, as Code Verify is bringing even more security to WhatsApp Web.\u00a0<\/span><\/p>\n

Code Verify works in partnership with Cloudflare, a web infrastructure and security company, to provide independent, third-party, transparent verification of the code you\u2019re being served on WhatsApp Web. We hope this gives at-risk users peace of mind.\u00a0<\/span><\/p>\n

No other end-to-end encrypted messaging service has this level of security for people\u2019s communications on the web. In addition to deploying Code Verify for WhatsApp Web, it is also being offered as open source so that other services can use it as well. Below is an overview of how Code Verify works, how to use it, and the value of open-sourcing it.\u00a0\u00a0<\/span><\/p>\n

How Code Verify works<\/h2>\n

Code Verify expands on the concept of <\/span>subresource integrity<\/span><\/a>, a security feature that lets web browsers verify that the resources they fetch haven\u2019t been manipulated. Subresource integrity applies only to single files, but Code Verify checks the resources on the entire webpage. To do this at scale, and to enhance trust in the process, Code Verify partners with Cloudflare to act as a trusted third party.\u00a0<\/span><\/p>\n

We\u2019ve given Cloudflare a cryptographic hash source of truth for WhatsApp Web\u2019s JavaScript code. When someone uses Code Verify, the extension automatically compares the code that runs on WhatsApp Web against the version of the code verified by WhatsApp and published on Cloudflare. If there are any inconsistencies, Code Verify will notify the user.<\/span><\/p>\n

While comparing hashes to detect files that have been tampered with is not new, Code Verify does so automatically, with the help of Cloudflare\u2019s third-party verification, and at this scale for the first time. <\/span>WhatsApp\u2019s security protections, the Code Verify extension, and Cloudflare all work together to provide real-time code verification. <\/span>Whenever the code for WhatsApp Web is updated, the cryptographic hash source of truth and extension will update automatically as well.\u00a0<\/span><\/p>\n

\"WhatsApp
Code Verify matches the WhatsApp Web code you\u2019re served with a source of truth verified by WhatsApp and published on Cloudflare to ensure the version of WhatsApp Web you\u2019re using is authentic. (Image source: Cloudflare)<\/figcaption><\/figure>\n

Cloudflare has provided a deeper dive on how this system works, including their role as a trusted third party, on their blog which can be found here<\/a>.\u00a0<\/span><\/p>\n

How to use Code Verify<\/span><\/h2>\n

The Code Verify extension is offered by <\/span>Meta Open Source<\/span><\/a> and will be available on the official browser extension stores for Google Chrome, Microsoft Edge, and Mozilla Firefox. <\/span>The extension doesn\u2019t log any data, metadata, or user data, and it does not share any information with WhatsApp. It also does not read or access the messages you send or receive. In fact, neither WhatsApp nor Meta will know whether someone has downloaded the Code Verify extension. Additionally, the Code Verify extension never sends messages or chats between WhatsApp users to Cloudflare.<\/span><\/p>\n

Once installed, Code Verify will run automatically when you go to WhatsApp Web and <\/span>act as a real-time alert system for the code you\u2019re being served on WhatsApp Web<\/span>. Pinning the extension to your web browser\u2019s toolbar will allow you to see its findings without any additional steps. You can think of Code Verify as a traffic light for your WhatsApp Web code:<\/span><\/p>\n