app-authentication

How to authenticate windows application against other application/COM Object

I have 3 components in my system: COM Object - Provide Services to application that has func1(), func2() App1 - Trusted Application that need to use the com object funcs (1 and 2) App2 - Malicious application, not authorized to use func1(), can use func2() it is not harmful. How can the COM Object can "authenticate" App1 and allowin...