Postman app - 403 Invalid client certificate

Question

I'm trying to test API that requires a client certificate with postman.

Postman app that comes with google chrome built in app works fine as it loads the correct certificate from user local store.

But this built in app will be deprecated soon. I'm trying to get Postman standalone app. I keep getting

403 Invalid client certificate

It requires the certificate to be loaded manually:

Questions:

I only have pfx certificate loaded on to my local certificate store.

1. How do I generate CRT file and key file off pfx
2. How do I generate passphrase

Thanks.

Answer 1

You can convert pfx certificate into cer and key files by using OpenSSL application (Windows installed can be found under https://slproweb.com/products/Win32OpenSSL.html). Once OpenSSL is installed, run PowerShell and execute the following commands.

openssl pkcs12 -in test.pfx -nocerts -out test.key

You will be asked to provide password to pfx certificate and set passphrase. Then execute the following commands and provide password to pfx certificate.

openssl pkcs12 -in test.pfx -clcerts -nokeys -out test.crt

In the case above, cer and key files will be stored under user's directory.