Free cryptography software for linux

CODEX is a software designed for applications with a moderate number of clients requesting authentication keys
When designing secure applications, it is not uncommon to assume some out-of-band mechanism for distributing keys or other secrets. Other applications without inherent security features could, given a key distribution system, employ symmetric key encryption to add a cryptographic access control mechanism. These applications motivated the development of the CODEX (the Cornell Data Exchange) key distribution system. CODEX is designed for applications with a moderate number of clients (tens or hundreds) requesting keys that change often but not continuously (on the scale of minutes to hours).
CODEX is an moving forward from the ideas implemented in COCA. It employs the RSA and ElGamal encryption schemes, as well as techniques such as threshold cryptography and proactive secret sharing. The COCA page contains a number of useful links for these topics.
Part of the development of CODEX was the creation of a general-purpose toolkit for the various primitives needed by the system. These primitives are discussed in the Implementation section, and the full source code is also available.
Since a random search on Google revealed that this project is now listed on Freshmeat, it is worth mentioning a few significant aspects of the implementation. First, the code is research-quality, not production-quality. The system employs spin-waiting, which can substantially impact the host on which a server runs. For an effective proactive-recovery system, servers must periodically be placed into a known-good state.
This typically involves rebooting from clean (and, if necessary, patched) media and installing new server-specific public/private key pairs, as well as the proactive secret sharing procedure included in the implementation. If, at this point, you still trust the implementation and your operating system enough to use CODEX, be advised that there is currently no credentials mechanism in place.
The existing policy object always accepts any credentials object as valid. Since the entire system depends on enforcing policies for access control, if you want to deploy a CODEX system (as opposed to using the libraries to build your own system) you must implement an actual policy/credentials mechanism.
Enhancements:
- This release was updated for compatibility with Doxygen 1.4.1 and to work with g++ through version 3.3.5.
- CODEX_Quorum/Socket.cc is now able to handle non-stream sockets (i.e. UDP).
- CODEX_Quorum/SocketBuilder.h now has a copy constructor.

The Legion of the Bouncy Castle Java Cryptography API provides a lightweight cryptography API in Java. A provider for the JCE and JCA, a clean-room implementation of the JCE 1.2.1, generators for Version 1 and Version 3 X.509 certificates, generators for Version 2 X.509 attribute certificates, PKCS12 support, and APIs for dealing with S/MIME, CMS, OCSP, TSP, and OpenPGP. Versions are provided for the J2ME, and JDK 1.0-1.5.
Main features:
- A lightweight cryptography API in Java.
- A provider for the JCE and JCA.
- A clean room implementation of the JCE 1.2.1.
- A library for reading and writing encoded ASN.1 objects.
- Generators for Version 1 and Version 3 X.509 certificates, Version 2 CRLs, and PKCS12 files.
- Generators for Version 2 X.509 attribute certificates.
- Generators/Processors for S/MIME and CMS (PKCS7).
- Generators/Processors for OCSP (RFC 2560).
- Generators/Processors for TSP (RFC 3161).
- Generators/Processors for OpenPGP (RFC 2440).
- A signed jar version suitable for JDK 1.4/1.5 and the Sun JCE.

CryptoServer is OpenSource Server-side cryptography tool and run as daemon.

It is already tested in very busy environment and can support over one million transaction an hour.

CryptoServer accept the GPL License and can use it for any purpose as is.

FlexiCrypt is a universal cryptography toolkit for managing certificates and symmetric keys. FlexiCrypt can perform many kinds of encryption, decryption, signing, and several related tasks.
Main features:
- key managing (asymmetric and symmetric)
- generate certificates
- symmetric encryption
- asymmetric encryption
- hybrid encryption
- decryption
- XML-signatures
- message digest computation
- secure file deletion (wipe files)
- performance comparison

libbasiccard is a library to access BasicCards (programmable smart cards). It closely follows the official APIs defined by ZeitControl (Cri, Bci, and zccrypt), extending them where needed. The project also includes support for the MultiApplication BasicCard and the BasicCard cryptography functions.
Enhancements:
- A port of the BasicCard cryptographic API (zccrypt) in the form of a new library called libbccrypto was added (elliptic curve cryptography support is available on request.)
- Support for all the commands of the MultiApplication BasicCard was added.

Cryptonit project is a client side cryptographic tool which allows you to encrypt/decrypt and sign/verify files with PKI (Public Key Infrastructure) certificates.
Main features:
- Encryption/decryption based on highly reliable algorithms
- Signature/verification procedures ensuring tamper-proof documents
- Use of passwords, certificates & smart (chip) cards for file encryption
- Address book for saving and organizing contacts
- Ability to import contacts and their certificates from the corporate directory (LDAP import)
- Multiple user account management
- Interfaces in both English and French
- CRL download
- RSA cryptography (public key cryptography standard)

epiOS is a Gentoo based GNU/Linux distribution designed and optimized for VIA Epia systems.

epiOS is developed to detect and support all integrated hardware components like the onboard MPEG-2 decoder or the PadLock (Cryptography) engine out of the box.

Otherwise its main purpose is to provide a system which is easy to install, maintain and of course very easy to use even for unexperienced users but keeping all the advanced features Gentoo provides.