DB user should not be able to find the other user names in the instatnce

[rao_manne]

How can a user created in Oracle DB, should not know other users names in the instance. Meaning how can I revoke the privilege to access all_tables view.

[reydp]

all_tables will only show tables that a user have been granted with privilege either directly to a user or thru role. query the dba_tab_privs:
select grantee, privilege, table_name from dba_tab_privs where grantee = 'YOURUSER';
or the role that being granted to the user:
select grantee, granted_role from dba_role_privs
where grantee = 'YOURUSER';

[rao_manne]

Thanks, Please let me know how one user can not know about the other usernames exisiting in the DB instatnce

[davey23uk]

dont think you can as the view all_users is granted to public and contains user information