The access control of a queue is first set when the queue is created (see Creating a Queue). However, MSMQ also provides two functions for managing access control after the queue is created: MQGetQueueSecurity and MQSetQueueSecurity.
Access control determines who can perform specific operations on the queue. Operations that can be set include creating, deleting, and opening the queue; sending messages to and reading messages from the queue; getting and setting the queue's properties; and getting and setting the queue's security descriptor. These operations can be restricted to a specific user or group of users.
For information on how MSMQ uses these settings, see Access Control.