The OpenSSL Project is a collaborative effort to develop a robust, commercial-grade, fully featured, and Open Source toolkit implementing the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) as well as a full-strength general-purpose cryptography library.
GnuPG (the GNU Privacy Guard or GPG) is GNU's tool for secure communication and data storage. It can be used to encrypt data and to create digital signatures. It includes an advanced key management facility and is compliant with the proposed OpenPGP Internet standard as described in RFC2440. As such, it is meant to be compatible with PGP from NAI, Inc. Because it does not use any patented algorithms, it can be used without any restrictions.
CryptoHeaven offers secure email and online file sharing/storage. Its main features are secure and highly encrypted services such as group collaboration, file sharing, email, online storage, and instant messaging. It integrates multi-user based security into email, instant messaging, and file storage and sharing in one unique package. It provides real time communication for text and data transfers in a multi-user secure environment. The security and usability of CryptoHeaven is well-balanced; even the no-so-technically oriented computer users can enjoy this crypto product with very high level of encryption.
The stunnel program is designed to work as an SSL encryption wrapper between remote client and local (inetd-startable) or remote server. It can be used to add SSL functionality to commonly used inetd daemons like POP2, POP3, and IMAP servers without any changes in the programs' code. It will negotiate an SSL connection using the OpenSSL or SSLeay libraries. It calls the underlying crypto libraries, so stunnel supports whatever cryptographic algorithms you compiled into your crypto package.
The CyaSSL embedded SSL library is a lightweight SSL library written in ANSI C and targeted for embedded and RTOS environments, primarily because of its small size, speed, and feature set. It is commonly used in standard operating environments and cloud services as well because of its royalty-free pricing and excellent cross platform support. CyaSSL supports industry standards up to the current TLS 1.2 and DTLS 1.2 levels, is up to 20 times smaller than OpenSSL, and offers progressive ciphers such as HC-128, RABBIT, and NTRU.
Bitcoin is a peer-to-peer electronic cash system that is completely decentralized, without the need for a central server or trusted parties. Users hold the crypto keys to their own money and transact directly with each other, with the help of a P2P network to check for double-spending.
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, CMP, CRMF, EAC, DVCS, OpenPGP, DTLS, and TLS. Versions are provided for the J2ME, and JDK 1.0-1.7.
haveged is a daemon that feeds the /dev/random pool on Linux using an adaptation of the HArdware Volatile Entropy Gathering and Expansion algorithm invented at IRISA. The implementation attempts to be self-tuning on a wide variety of hardware and includes runtime validation testing. The tarball uses the GNU build mechanism and includes a devel sub-package, self test targets, init system options, and spec file samples for building an RPM. haveged may be used independently of the /dev/random interface through the filesystem at the command line. haveged functionality may be incorporated directly into other components directly through the devel sub-package.