Yes, The role based security can be applied to the individual operation contract in WCF services.
if we have the set of users under the particular role, we can provide the security so that only particular group of user can get those operations when consuming the service.
To assign the security based on the operation, we have the predefined annotation PrincipalPermission which can be set as:
[PrincipalPermission(SecurityAction. Demand,Role = "Role1")]
[PrincipalPermission(SecurityAction. Demand,Role = "Role2")]
Hope it will be helpful to you.
Pawan Awasthi(DNS MVM)
+91 8123489140 (whatsApp), +60 14365 1476(Malaysia)