You can achieve this using OpenSSL. (Mac OSX includes OpenSSL within Terminal.app)
SHA is a popular hashing algorithm used by the majority of SSL certificates. As computing power has increased the feasibility of breaking the SHA1 hash has increased.
A warning is displayed in the Chrome console window regarding your certificate
This usually means the implementation of SSL on your server is not correct. The error is usually caused by a server side problem which the server administrator will need to investigate.
This message is sometimes displayed when accessing an SSL page via a proxy (including our own payment page PayPal).