For generic encryption, I have came upon Lua Lockbox, which is a native lua implementation of many security algorithms (but not a random generator). Being native Lua it may not give very best performance, but for occasional encryption that may not be an issue.
Regarding TLS, I like the idea of extracting the abstraction layer from libcurl. I have very little experience with c, and also not with linux and mac os, so I am unable to do this myself or to help here.
Is this something that that you can and/or would like to do? In my opinion, it would be a huge complement to your framework to be able to 'speak ssl without hassle'.
First of all, thanks for the great work! It's amazing that you seem to be about the only one in the world that is not willing to build everything from source!
What I miss in your library is encryption and SSL. You do have libssh2 (but as far as I can see, for windows only?) and libcurl (which, as you indicate, use the native windows encryption library and for linux uses openssl, but is for fetching files only, not for generic encryption or ssl).
What I am looking for is a cross-platform solution, that offers both the primitives (ciphers, hashing, random generator, signing) as well as SSL. Preferably using the native OS libraries, instead of addons such as openssl.
Because most of the required ingredients are already provided by libcurl, would it be hard to make such an encryption/ssl library? Or is it already there, and did I complete miss it?