I am using Windows and have been given a .cer file. Where can i see what information i have?
OpenSSL will allow you to look at it if it is installed on your system, using the OpenSSL x509 tool .
openssl x509 -in cerfile.cer -noout -text
The format of the .CER file might require that you specify a different encoding format to be explicitly called out.
openssl x509 -inform pem -in cerfile.cer -noout -text
openssl x509 -inform der -in cerfile.cer -noout -text
On Windows systems you can right click the .cer file and select Open. You can then see most of the meta data
On Windows you run Windows certificate manager program using certmgr.msc command in the run window. You then import your certificates and see the details