Free security library software for linux

GNU Transport Layer Security Library is a library which implements a secure layer over a reliable transport layer such as TCP/IP. GNU Transport Layer Security Library implements the TLS 1.0 and SSL 3.0 protocols, accompanied with authentication methods such as X.509, OpenPGP, and SRP.
Main features:
- Support for TLS 1.1 and SSL 3.0 protocols
- Support for TLS extensions
- Support for authentication using the SRP protocol
- Support for authentication using both X.509 certificates
- and OpenPGP keys Support for X.509 and OpenPGP certificate handling.
- Supports all the strong encryption algorithms
- Supports compression
- Runs on most Unix platforms
Enhancements:
- Support for Proxy Certificates as per RFC 3820 were added.
- The --generate-proxy option was added to certtool.
- certtool --certificate-info now prints information for Proxy Certificates.
- New APIs were added to set proxy subject names and get or set a proxy cert extension.
- Parsing of pathLenConstraints in BasicConstraints with missing CA was fixed.
- A self-test was added to test for regressions of pathLenConstraint.
- Certtool now prints times in UTC when printing certificate/CRL info.
- Importing of ASCII armored OpenPGP keys was fixed.

ShmFIFO library provides an easy-to-use interface to shared memory for programs where one process needs to send blocks of data to other processes.

It was developed because pipe(2) and mkfifo(3) have a very small buffer size (4k) and are unsuitable for many applications. Shmfifo allows you to put a block of data in shared memory, get the oldest block of data from shared memory.

ShmFIFO library also has the feature to share one instance of a private data structure among all processes which use the library.

How to use shmfifo

Before using, shared memory should be created. After creating shared memory, process which wants to use it, should attach to memory. Then it can put and get blocks to FIFO. After process is finished working with FIFO, it calls shfifo_detach. When no processes will use FIFO, shared memory should be deallocated.

Usally, lifecycle of shmfifo-based program is following:

[parent] shmfifo_create
[parent] fork(2)
[both] shmfifo_attach
[both] shmfifo_put, shmfifo_get (many times)
[both] shmfifo_detach
[parent] wait(2) or waitpid(2)
[child] exit
[parent] shmfifo_dealloc

shmfifo comes with test.c program, which is good sample of how to write programs with shmfifo. It forks into 2 processes, parent generated variable-length blocks, writes checksum into each block and put it into FIFO. Child gets blocks from fifo, check if checksum is valid (its always valid if there is no bug in program) and prints debug info. after large number of blocks gets transferred, both processes are exit.

Additionally, shmfifo allows processes to share one private structure. test.c uses this structure to store counter, which is increased each time when parent cannot put block to FIFO because its already full and has to wait until child will get block. If small amount of memory allocated for FIFO, then parent will wait more often.

Installation:

make
make test
su -
make install

test.c is sample test program which is builts into test binary. You can run it to test if library is working

GNU Generic Security Service Library provides a Generic Security Service (GSS-API) implementation.

It is used by network applications to provide security services, such as authenticating SMTP/IMAP, via the GSSAPI SASL mechanism.

It consists of a library and a manual, and a Kerberos 5 mechanism that supports mutual authentication and the DES and 3DES ciphers.

GNU C library (glibc) is one of the most important components of GNU Hurd and most modern Linux distributions.

GNU C library is used by almost all C programs and provides the most essential program interface.

The history of Unix and various standards determine much of the interface of the C library. In general the GNU C library supports the ISO C and POSIX standards. We also try to support the features of popular Unix variants (including BSD and System V) when those do not conflict with the standards. Different compatibility modes (selectable when you compile an application) allow the peaceful coexistence of compatibility support for different varieties of Unix.

The GNU C library is primarily designed to be a portable and high performance C library.

It follows all relevant standards (ISO C 99, POSIX.1c, POSIX.1j, POSIX.1d, Unix98, Single Unix Specification). It is also internationalized and has one of the most complete internationalization interfaces known.

conexus is a generalized C++ I/O library that includes support for BSD sockets, serial/TTY, and packet capture (via pcap).

conexus library utilizes sigc++ for object communication. A companion library, conexusgtk, provides a set of gtkmm widgets.

Meta Matrix Library is a modular designed collection of C libraries. Meta Matrix Library was developed as part of the Free Finite Element Package to provide easy and consistent access to numerical linear algebra software for sparse and dense matrices.

The dense matrix and vector operations of the package are based on LAPACK and BLAS (focused upon ATLAS). For more details of LAPACK and BLAS see Related Links. Beyond this MEML supports UMFPACK ( SuperLU projected ) as solver for linear systems of equations with sparse matrices.

DBPrim project is a library providing basic building blocks for creating in-memory databases.
Main features:
- Linked lists
- Hash tables with optional auto-resize
- Memory-efficient sparse matrices built on hash tables
- Red-black trees.