Establishment of IPsec Security Associations with Diffie–Hellman following a SDN-based framework: Analysis and practical validation

The centralized management of IPsec Security Associations (SAs) by using Software Defined Network (SDN) paradigm has been already explored and standardized. Datacenters are some of the scenarios where the dynamic establishment of IPsec security associations among network nodes has been deemed relevant. In these scenarios, where nodes do not support protocols like IKEv2, applying solutions where the generation and distribution of keys for IPsec are delegated to the SDN controller. However, these scenarios have the issue that the controller itself generates the IPsec keys for the nodes, posing a higher risk to the system’s security in case the controller is compromised. For these scenarios, it would be necessary to define solutions that allow the distribution of this cryptographic material securely, while maintaining the capacity restrictions established by the nodes. To solve this risk, we propose the generation of the IPsec keys using key distribution through the Diffie–Hellman algorithm in such a manner, that the controller will never have access to the IPsec SAs session keys used by the network nodes, mitigating the aforementioned problem. In concrete, our approach makes the nodes responsible for generating their own Diffie–Hellman public and private keypair, while the controller is only in charge of distributing the public keys to the rest of nodes, as well as other parameters needed to install the IPsec SAs. As we will analyze, the distribution of the public keys will be enough to allow the network nodes to generate the session keys. This work presents the design, implementation and validation of this IPsec management solution based on Diffie–Hellman in SDN environments using asymmetric key distribution for negotiating encryption and integrity keys, focusing on the performance in key generation and installation of IPsec SAs.