Step 1: Install OpenSSL for Windows 3.4 Step 2: Run Windows cmd prompt Step 3: Run the command line to get the .per format: openssl x509 -in star_abccer.crt -out cert.pem or run this command to get .pfx format openssl pkcs12 -export -out certificate.pfx -inkey abccer.key -in star_abccer.crt -certfile abccerca.crt For example: Ref: https://www.youtube.com/watch?v=-SpFcBfwfZY&t=35s