User authentication on Web service

Hello Gurus,

We are calling a webservice from oracle (external system) and pass username and password.

Now, because of company compliance we cannot pass the username and password via URL when calling a web-service. The only option I am told is to go for X.509 certificates (user authentication via certificates).

I have checked Sap system, SNC is already configured.

Kindly, advice how should I implement the solution to apply/generate certificate and using it on the external system.

Question: Does SSO needa to be configured to generate a certificate?

Question: How to Generate (Sap system) and consume certificate (External system)?

Any step by step document would be real help.

Regards,

Abhishek.