In M56, we will no longer support sites that use SHA1 certificates per http://crbug.com/652527

Visiting a test site like https://sha1.badssl.com/ in M56+ shows:

========

Your connection is not private

Attackers might be trying to steal your information from sha1.badssl.com (for example, passwords, messages, or credit cards). NET::ERR_CERT_WEAK_SIGNATURE_ALGORITHM
  
Automatically report details of possible security incidents to Google. Privacy policy

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This error message is not user friendly as the user has no idea why the site is not working. Additionally, it will be hard for gCon to separate out users who have encountered a site with this error from a user who is encountering another problem like captive portal, HSTS, ect. We've found in user feedback that the user searches for help content on "Your connection is not private" and do not specifically search for "ERR_CERT_WEAK_SIGNATURE_ALGORITHM".

Can we make the following request:
1) Have a dedicated error string specifically mentioning SHA1
2) Let the user know in the error message (or link to help content) so that the user is aware they cannot access the site, and that the website owner will need to update their certificate? It is super frustrating for the user who spends time trying to troubleshoot an error they cannot fix. (Our help center already has steps to fix general Connection Not Private errors: https://support.google.com/chrome/answer/6098869?hl=en, and the user may try these steps in vain)

Example user report: 
https://hotsauce.corp.google.com/product/237/neutron?rPaneMode=auto&lView=rd&rView=tl&lRSort=1&lROrder=2&lRFilter=1&lReportSearch=ERR_CERT_WEAK_SIGNATURE_ALGORITHM&lReport=50255126458
 

In M56, we will no longer support sites that use SHA1 certificates per http://crbug.com/652527

Visiting a test site like https://sha1.badssl.com/ in M56+ shows:

========

Your connection is not private

Attackers might be trying to steal your information from sha1.badssl.com (for example, passwords, messages, or credit cards). NET::ERR_CERT_WEAK_SIGNATURE_ALGORITHM
  
Automatically report details of possible security incidents to Google. Privacy policy

========

This error message is not user friendly as the user has no idea why the site is not working. Additionally, it will be hard for gCon to separate out users who have encountered a site with this error from a user who is encountering another problem like captive portal, HSTS, ect. We've found in user feedback that the user searches for help content on "Your connection is not private" and do not specifically search for "ERR_CERT_WEAK_SIGNATURE_ALGORITHM".

Can we make the following request:
1) Have a dedicated error string specifically mentioning SHA1
2) Let the user know in the error message (or link to help content) so that the user is aware they cannot access the site, and that the website owner will need to update their certificate? It is super frustrating for the user who spends time trying to troubleshoot an error they cannot fix. (Our help center already has steps to fix general Connection Not Private errors: https://support.google.com/chrome/answer/6098869?hl=en, and the user may try these steps in vain)

Example user report: 
https://goto.google.com/crbug-675229-report