https://datatracker.ietf.org/doc/draft-mcdonald-simple-ipsec-api/
draft-mcdonald-simple-ipsec-api-02 - A Simple IP Security API Extension to BSD Sockets
In order to take advantage of the IP Security Architecture [Atk95], an application should be able to tell the system what IP-layer security services it needs...
ip securitybsd socketsdraftmcdonaldsimple