Difference between self-signed CA and self-signed certificate

Question

I\'m not clear on the difference between a CA key and a certificate. Isn\'t a CA key simply a certificate? Let me try and clarify with an example.

I have a client

Answer 1

You can openssl x509 -noout -text -in $YOUR_CERT to see the differences between files contents:

In your self-signed CA, you can see：

    X509v3 extensions:                                                          
        X509v3 Basic Constraints:
            CA:TRUE, pathlen:0

And in your self-signed certificate, it's:

    X509v3 extensions:                                                          
        X509v3 Basic Constraints:
            CA:FALSE