Protect Chrome users from attackers who might use the broken SHA-1 hash algorithm to obtain counterfeit website authentication certificates.
Docs: https://security.googleblog.com/2014/09/gradually-sunsetting-sha-1.html https://security.googleblog.com/2015/12/an-update-on-sha-1-certificates-in.html https://sites.google.com/a/chromium.org/dev/Home/chromium-security/education/tls/sha-1