| Function | Layer | Implementation | 
|---|---|---|
| Establish system (not user) trust | DNS SEC | BIND 8.2+(soon) | 
| pre-shared secret key | ASCII string | |
| pre-shared public key | RSA key | |
| Set up keys | manual | hexadecimal string | 
| IKE(ISAKMP/OAKLEY) | FreeS/WAN Pluto (userspace) | |
| Photuris | none (yet) | |
| Protect information | IPSEC | FreeS/WAN KLIPS (kernel) |