After WhatsApp‘s developer team enabled simultaneous multi-device support on its beta version, it also announced a new browser extension.
This add-on is called Code Verify and its sole purpose is to ensure that the web version of WhatsApp is safe enough and that end-to-end encryption has not been compromised.
WhatsApp claims that just shortly after it launched the multi-device support, it has actually been witnessing an increase in the number of WhatsApp web logins. The web app is naturally more susceptible to attacks, so the Code Verify essentially ensures that it also gets the same level of security as the native app on Windows, iOS, or Android.
The browser extension is very simple, it just compares the presented hash code with the one uploaded to a trusted and secure Cloudflare. If all is well, then the extension allows you to access your conversations.