End-to-end encryption at the network layer

Both network-layer and transport-layer encryption are permitted by the OSI Security Addendum. The advantages of network-layer encryption are discussed. Secure data network system (SDNS) protocols are described. In the SDNS, SP is a single, simple encryption protocol between end-systems. This protocol has two descriptions, SP3 (network layer) and SP4 (transport layer). Both definitions are OSI compliant. Extensions of the basic protocol allow SP3 to be used at intermediate systems and allow SP4 to provide a more connection-oriented service.<
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