IPsec (3)

IPsec on OpenBSD consists of two main programms

isakmpd(8), IKE key management daemon

This daemon is responsible for establishing security associations for encrypted and authenticated network traffic

Traditionally it was configured through isakmpd.conf(5) 
Of course this daemon is privilege seperated

In OpenBSD 3.8 ipsecctl(8) got introduced, makes setting up IPsec soooo much easier

ipsecctl(8) parses the config file /etc/ipsec.conf 

used to configure flows

retrieval of information from the kernel's Security Policy Database (SPD) and Security Association Database (SAD)