handling certificates in protractor

问题:

I am trying to automate angularjs application using protractor which asks to select a certificate to authenticate as shown below.

Certificate for authentication:

I am unable to interact with it by following below ways.

1.  browser.actions().sendKeys(protractor.Key.ENTER).perform();
2.  browser.switchTo().activeElement().sendKeys(keys.ENTER);
3.  browser.switchTo().alert().accept();
4.  using Robot class as we do in webdriver 

I am not able to proceed until I crosses this authentication. Once the certificate is selected it prompts to enter some PIN as shown in attachment.

Authentication using PIN:

.