User Creation for Siebel Application:

Run the below SQL query @Database level along with sys or system privileges

create user username identified by password;
grant sse_role to username;


Register the user in Siebel UI:

Go to site map-> administration-user -> Employee

Create new record for the user along with relevant privileges.

after that logout and log in to check the access in Siebel application using New user.

Finding Encryption Key for User in Siebel

To find Encryption Key in Siebel to connect local database you can use below query providing USER ID.
SELECT PREF_CD, VAL FROM SIEBEL.S_NODE_PREF s1, SIEBEL.S_NODE s2 WHERE s1.PREF_CD =’RemLocSec:PlainKey’ AND s1.NODE_ID = s2.ROW_ID AND s2.NAME =’USER ID’