A few months ago I offered to help with testing web browser implementations of the Web Cryptography API. I’d never written any tests using the Test the Web Forward frameworks, but I figured I could add a test case or two to other people’s tests.
It didn’t work out that way. I ended up writing tests for the entire subtle crypto API. Which was quite a challenge for someone who didn’t know how to do that. But I learned by doing, and the resulting tests helped show that the specification is already well supported in enough browsers to qualify for advancement to a W3C recommendation. They also uncovered a few bugs, most of which are very minor. But they’ve been reported to the browser makers and many have already been fixed.
You can do the same thing thing to help advance the state of the web. If you encounter inconsistent or apparently wrong behavior in any web browser, why not write a test and submit it to the W3C web-platform-tests repository as a pull request? You’ll be helping the web be more useful and reliable if you do.
Charles Engelke's Blog 
Can I ask you about your digital signature post two years ago..Can the button sign and verify separate ? I mean one person can sign the file and sent to others. The person that received the file can verify the file that was submitted.
Comment by syifazaidi — October 26, 2016 @ 4:01 am