BeeCrypt is an ongoing project to provide strong and fast cryptography in the form of a toolkit usable by commercial and open source projects. Included in the library are entropy sources, random generators, block ciphers, hash functions, message authentication codes, multiprecision integer routines, and public key primitives.
PLIB is a set of libraries to write games and other realtime interactive applications that are 100% portable across a wide range of hardware and operating systems. It's used by Majik3D, FlightGear, and others, and includes libraries for GUI widgets, sound replay, geometry, scene graph, joystick, and fonts/text.
OpenSC provides a set of libraries and utilities to work with smart cards. Its main focus is on cards that support cryptographic operations, and facilitates their use in security applications such as authentication, mail encryption, and digital signatures. OpenSC implements the PKCS#11 API so that applications supporting this API (such as Mozilla Firefox and Thunderbird) can use it. On the card, OpenSC implements the PKCS#15 standard, and aims to be compatible with every software/card that does so.
OpenXAdES enables people to work with legally-binding digital signatures (primarily giving and verifying them). Legislation often defines a set of requirements that legal digital signature technologies and infrastructures must be compliant with, and OpenXAdES aims at meeting many, if not all, such requirements from different legislations.
GNU SASL is an implementation of the Simple Authentication and Security Layer framework and a few common SASL mechanisms. SASL is used by network servers such as IMAP and SMTP to request authentication from clients, and in clients to authenticate against servers. The library includes support for the SASL framework (with authentication functions and application data privacy and integrity functions) and at least partial support for the CRAM-MD5, EXTERNAL, GSSAPI, ANONYMOUS, PLAIN, SECURID, DIGEST-MD5, LOGIN, NTLM, and KERBEROS_V5 mechanisms.
TnFOX is a modern secure, robust, multithreaded, exception aware, internationalizable, portable GUI toolkit library designed for mission-critical work in C++ and Python, forked from the FOX library. It replicates the Qt API in many places, comes with a full set of Python bindings, and has been designed primarily for Tn, the port of Tornado to FOX.
MpNT is a multi-precision number theory library that provides a base for building cryptographic applications. It may also be used in any other domain where efficient large number computations are required. The library supports integer, modular, and floating point arithmetic with practically unlimited precision. It is both speed efficient and highly portable without disregarding code structure and clarity.