Security Association (SA) is a fundamental concept in IPsec. A Security Association is a data structure that specifies communication security properties between IPsec nodes. To communicate, these nodes need at least one Security Association between them. A Security Association is identified by the following three parameters:
Security Parameter Index (SPI), which is an arbitrary 32-bit number
Destination IP address
Security protocol identifier (AH or ESP)
Security Associations contain cryptographic keys, algorithm types, addresses of communicating nodes, and other information. They are stored in a repository called Security Associations Database (SADB). In Solaris 8, the Security Associations Database is accessed using ...