In this paper we identify and address the challenges unique to providing a secure ATM network. We analyse the network environment and consider the correct placement of security mechanisms, with particular attention to data transfer protection, in such an environment. We then introduce and describe a key agile cryptographic device for ATM networks. We present the techniques to provide data confidentiality, synchronisation, dynamic key change, dynamic initialisation vector change, data integrity and replay protection on ATM data transfer. Finally, we discuss the corresponding control functions for setting up such a secure channel. We examine the impact of key exchange protocols on the design of ATM signalling protocols. Our effort in providing novel security services in ATM signalling systems has also been presented.