What are some "robust crypto tools" that are available for unix, and also aren't available for DOS/Windows?

Mixmaster, CFS, premail, the alias system at alpha.c2.org, etc. I know there are similar versions of some of these on pc boxes (sfs, secure drive, and private idaho), and those are good packages. But using private idaho on a pc is still a lot more of a hassle than using premail on a unix box (the latter can be completely transparent), and although I haven't seen the source code to private idaho, I'll be willing to bet it's a lot more complicated than the premail script. If you want to do something like Raph's remailer list, would you rather implement it on a pc running windows or with a perl script on a unix box? SFS is a great program, it works well, and it's very useful. But the design of CFS, which runs as an NFS server, is more elegant. Would you rather drop a new cipher into secure drive or sfs, or into CFS?

I kinda think the reason more tools aren't available for PCs (Windows/Mac) is because there is no appreciable MARKET for such tools yet. If there were, since PCs have a market share an order of magnitude or two larger than unix, such tools would have a greater influence anyway.

Did the market produce these unix tools? If Zimmermann was a businessman, wouldn't he have produced weak exportable code? Sometimes innovative products create the market, rather than the other way around. If there's a market for remailers, I'm inclined to think it's because we were able to glimpse the possibilities thanks to the original perl based type I remailer. As I said before, unix has a lot of problems. It's a crummy os if you want to write letters or do desktop publishing: even if you have good software to do these things, the system's going to cost you too much if that's all you're using your computer for. But if have an idea for a remailer and you'd like to throw something together over a weekend that will work, it's hard to beat it.