winsipolicy.p7b

PKCS #7 certificate file Reference

A .p7b file contains certificates in the PKCS #7 format. One file can hold a full certificate chain, but no private keys. Administrators use the format to move certificates between systems. Windows opens the file directly in the certificate viewer. The related extension .p7c means the same format.

A file extension is only a part of the file name. It does not give a guarantee about the format or the content of a file. But on Windows, the extension selects the program that opens the file.