http://nacl.cr.yp.to/index.html
Introduction
NaCl (pronounced "salt") is a new easy-to-use high-speed software library for
network communication, encryption, decryption, signatures, etc. NaCl's goal is
to provide all of the core operations needed to build higher-level cryptographic
tools.
Of course, other libraries already exist for these core operations. NaCl advances
the state of the art by improving security, by improving usability, and by
improving speed.
The following report contrasts NaCl with other libraries from a security perspective:
(PDF) Daniel J. Bernstein, Tanja Lange, Peter Schwabe, "The security impact of a new
cryptographic library". Pages 159–176 in Proceedings of LatinCrypt 2012, edited by
Alejandro Hevia and Gregory Neven, Lecture Notes in Computer Science 7533, Springer,
2012. ISBN 978-3-642-33480-1.
http://nacl.cr.yp.to/features.html
No copyright restrictions
All of the NaCl software is in the public domain.