I just released a module for working with the nettle cryptographic library.
http://newlisp-on-noodles.org/wiki/index.php/Nettles
Enjoy!
PS - I haven't been able to get it to work on Mac OS X. Nettle is in Fink but there's no dylib. If anyone knows how to make libnettle.dylib from libnettle.a I'd appreciate a tutorial in converting. For now it's been tested with Linux only.