According to today's headline data, the sa(SecurityAssociation) security alliance is to establish an agreement on tunnel parameters between the communication parties of an IPSec tunnel, including IP addresses at both ends of the tunnel, authentication methods adopted by the tunnel, authentication algorithms, authentication keys, encryption algorithms, encryption keys, * * * * shared keys, life cycle and a series of parameters.
According to today's headlines, sa determines the IPsec protocol, transcoding method, key and the effective existence time of the key. Any IPsec implementation will always build an sa database to maintain IPsec protocol and ensure the security of packets.