openssl for Windows

Question:

Where can I find the openssl command line tool for Windows?

Answer:

The openssl command line utility comes with Unix, but not with Windows. It is used for working with security certificates.

The main site is

https://www.openssl.org/

There are no binaries on this site but in the Community section there is a link for binaries which leads to:

https://www.openssl.org/community/binaries.html

This contains a link to "An informal list of third party engines":

https://wiki.openssl.org/index.php/Binaries

At the time of writing this had two entries for OpenSSL for Windows. I chose the first one:

https://slproweb.com/products/Win32OpenSSL.html

On this page there are several options. For 64 bit Windows I chose this one: "Win64 OpenSSL v1.1.0c Light".

I installed and ran this on Windows 10 successfully.

For example:

1. Convert certificate from binary to PEM format:

[install_dir]\bin\openssl x509 -in cert.cer -inform der -outform pem -out cert.pem

2. Display binary certificate as text:

[install_dir]\bin\openssl x509 -in cert.cer -inform der - text

You can find the Unix man pages here:

https://linux.die.net/man/1/openssl