Mountain View says it's hoping you don't ever encounter the message, because Certificate Authorities are required to stop issuing SHA-1 certificates in 2016. Just in case, Google plans to continue issuing warnings until Chrome completely stops supporting SHA-1 on January 1st, 2017. When that day comes, a website that still uses the function will trigger a fatal network error.

SHA-1 has been growing weaker and more insecure everyday for a decade now, which is dangerous considering we tend to trust websites with "https://" in their URLs. Other browsers like Mozilla Firefox and Microsoft Edge also plan to stop supporting it in an effort to encourage website owners to switch to more secure SHA-2 certificates as soon as possible.