Getting an error while generating ssl certificates

On Windows you can also set the environment property OPENSSL_CONF. For example from the commandline you can type:

set OPENSSL_CONF=c:/libs/openssl-0.9.8k/openssl.cnf

to validate it you can type:

echo %OPENSSL_CONF%

You can also set it as part of the computer's environmental variables so all users and services have it available by default. See, for example, Environment variables in Windows NT and How To Manage Environment Variables in Windows XP.

Now you can run openssl commands without having to pass the config location parameter.

You can do that in one command:

openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -sha256 -days 365

You can also add -nodes (short for no DES) if you don't want to protect your private key with a passphrase. Otherwise it will prompt you for "at least a 4 character" password.

The days parameter (365) you can replace with any number to affect the expiration date. It will then prompt you for things like "Country Name", but you can just hit Enter and accept the defaults.

Add -subj '/CN=localhost' to suppress questions about the contents of the certificate (replace localhost with your desired domain).

Self-signed certificates are not validated with any third party unless you import them to the browsers previously. If you need more security, you should use a certificate signed by a certificate authority (CA).