Last updated: 14/01/2016
Server Gated Cryptography (SGC) is a technology that allows older browsers to seamlessly step up the weak 40-bit encryption they use to a strong encryption rate using 128 bits. Certain certificate authorities, such as Symantec/Verisign, Thawte and Comodo offer SGC versions of their SSL certificates, usually at a significantly higher cost, up to 50% more than the non-SGC version of the same certificate.
SGC was created in response to the restrictions the US government imposed on the export of strong cryptography in the 1990s. By 2000, those restrictions were dropped, and browser manufacturers such as Microsoft started releasing browsers with 128-bit SSL encryption built-in, starting with Internet Explorer 5.0.1 SP1 and Internet Explorer 5.5. Over the years, the percentage of browsers not capable of using 128-bit encryption has steadily dropped.
According to W3 Schools, usage of Internet Explorer 4 and 5 has dropped to 0.0% in October 2014, making SGC SSL certificates no longer cost-effective or even remotely useful to buy.
In addition, GlobalSign, one of the premium Certificate Authorities, explicitly takes a stand against SGC SSL Certificates.
Thawte, Comodo and Symantec each have an SGC SSL certificate in their product line-up. Please visit Kinamo's SSL Certificates page to find out which SSL certificate is exactly fits your needs.