For mac users, there is a trick for export certificate public key from chrome. Follow these steps : 
For mac users, there is a trick for export certificate public key from chrome. Follow these steps : 1. Open Google Chrome, go to the site. For example, I want to get a google certificate.
2. Click the icon to the left of the URL in the address bar.
3. Click Certificate
4. Arrange windows so that the Chrome window and the Desktop window are both visible.
5a. If you want to get a .cer certificate, drag from the large certificate icon to the desktop.
5b. If you want to get a .pem certificate, hold down option, and drag from the large certificate icon to the desktop.
