As you saw in Chapter 7, security is an essential part of any distributed application, and COM+ provides you with a rich, user-friendly security infrastructure. When a client makes a queued call, the queued component may still require the same level of security services and protection as if it were invoked synchronously, and rely on COM+ to provide authentication and authorization.
However, the underlying method call invocation is different, and the synchronous security mechanism simply will not do—by the time the actual object is invoked, the client may be long gone (with its security identity and credentials). The synchronous authentication that uses the challenge-response mechanism cannot be used.
The idea behind queued component security is simple—have the recorder capture the security identity (and other security-related information) of the client as it records the method calls. The security information is bundled in the message along with the method calls and sent to the queued component application queue. Before the player makes the call on the component itself, COM+ uses the captured security information to validate that the client is allowed to access the component.
The underlying implementation of this idea relies heavily on MSMQ security services to capture the client security details in the message and transfer it securely to the application queue. To ensure authenticity of the message, the messages can carry a digital signature from the client. ...