The SHA-1 algorithm is aging due to both mathematical and technological advances. This poses a risk to digital signatures incorporating the SHA-1 algorithm since they may soon be forgeable.
Most browser vendors have a SHA-1 deprecation plan and will soon show warnings when users are visiting a site using such a certificate. Read more from
Google, Microsoft or Mozilla.
This site provides an Internet-Wide overview of the SHA-1 usage. More than 475 Million hostnames have been queried resulting in more than 90 Million successful SSL Handshakes.
As of February 2017 the global SHA-1 average was 6.3%. In January 2017 the average was 6.5 and in December 2016 the average was 7.7%.
The certificates were retrieved in the period 5 - 7/FEB/2017. Only countries with more than 1,000 SSL enabled hosts are colored.