There are of course other Open Source projects that implement IKE, the two most widely known being the Linux FreeS/WAN project's Pluto, and Racoon, of the KAME project whose IPsec stacks exist for both NetBSD and FreeBSD. Both of these are only meant for their respective platforms, unlike isakmpd, which is meant to be a portable implementation. As a matter of fact, isakmpd runs on top of both the FreeS/WAN and KAME stacks. Racoon is, to our knowledge, the only IKE implementation with IPv6 support. There are also other key-management protocol implementations available, an example is photurisd, OpenBSD's Photuris implementation. An extensive overview of the employment of cryptography in OpenBSD may be found in [8].