The following are binaries for the S/Key generation ultility, "key".

key.exe		- DOS
key.hqx		- MAC
winkey.exe      - Microsoft Windows
sunos5.key.Z	- SunOS 5.x (Solaris 2.x)
sunos4.key.Z	- SunOS 4.x (Solaris 1.x)
ultrix4.key.Z   - Ultrix 4.x

key.tar.Z is the source code for the above.