Information about the .cer (cer) file type

Below is all the information we have available on file about the .cer (cer) file type.

.cer
Certificate file. A security certificate.

Security certificates have a number of different roles. Typically they are used as part of the process of providing secure access to a website (i.e. https), in which case the certificate is generally provided by a trusted third party. It is also possible for a website to generate its own certificate in which case it is said to be self certificated, but these are uncommon because as a user would see a configuration dialog because the certificate would not then be from a trusted source.

Certificates are also used by the EFS recovery agent to enable a trusted account to be able to recover encrypted files.

Security certificates can have different file formats, but the following formats are widely supported:

  • DER encoded binary X.509
  • Base-64 encoded X.509

cf .crt, .der

Where this is available we would like to include file format information on .cer files, as well as information on how to view or open files of type .cer. If you know of any information which we have missed then please let us know.