Systems and methods are provided for managing and distributing keys between routers using protocol exchange messages between routers as key distribution vehicles. According to one embodiment of the invention, a router of an autonomous system uses its private key to send cryptographic information associated with another router to a peer router as part of its protocol exchange messages. The peer router is able to extract the cryptographic information and store it in a look-up table. Such protocol exchange messages may occur as part of an Interior Gateway Protocol or an Exterior Gateway Protocol. According to another embodiment of the invention, a chain authentication system is created as boundary routers of autonomous systems having a trust relationship share cryptographic information for other autonomous systems as part of protocol exchange messages for the exterior gateway protocol.