Creating test certificates for 802.1x

Note: If you're using Windows and using gitbash, prefix all the commands with winpty so as to ensure openssl captures input correctly.

1. Create the CA Private Key:

First, we will create our own Certificate Authority (CA). Initially, we will make a private key for the CA.

openssl genpkey -algorithm RSA -out ca.key -aes256

You will be asked to set a password for this key, please make sure to remember it as it's required for the next steps.

2. Create the Root Certificate (CA Certificate):

Next, we will use the private key to create a new root certificate (CA certificate) which can be used to sign client certificates.

openssl req -x509 -new -nodes -key ca.key -sha256 -days 1024 -out ca.crt

You will be asked to provide details for the certificate like Country, State, etc.

3. Create Client Private Key:

Now, let's create the client's private key.

openssl genpkey -algorithm RSA -out mydomain.key

4. Create a Certificate Signing Request (CSR) for the Client:

We will now create a certificate signing request (CSR) for the client's private key.

openssl req -new -key mydomain.key -out mydomain.csr

You will be asked again to provide details like before.

5. Sign the CSR with our CA:

Now we will use the CA to sign the client's CSR and get back the client certificate.

openssl x509 -req -in mydomain.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out mydomain.crt -days 1024 -sha256

The client certificate (mydomain.crt) is now signed by the CA and can be used in client applications.