Programmable networks aim at the fast and flexible creation of services within a network. Often cited examples are audio and video transcoding, application layer multicast, or mobility and resilience support. In order to become commercially viable, programmable networks must provide authentication, authorization and accounting functionality. The mechanisms used to achieve these functionalities must be secure, reliable, and scalable, to be used in production scale programmable networks. Additionally, programmable nodes must resist various kinds of attacks, such as denial of service or replay attacks. Fraudulent use by individual users must also be prohibited. This paper describes the design and implementation of an <em>secure, reliable, and scalable</em> signaling mechanism clients can use to initiate service startup and to manage services running on the nodes of a programmable network. This mechanism is designed for production scale networks with AAA-functionality.