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.
yaSSL is a C++ based SSL library for embedded and RTOS environments, designed for individuals who prefer to use the C++ language. For a C-based solution, please see CyaSSL. yaSSL supports the industry standards up to TLS 1.2, and also includes an OpenSSL compatibility interface.
KCrypto is a KDE2 file encryptor. It uses the Rijndael public domain C++ class implementation, and is capable of encrypting and decrypting every kind of file (text and binary) in CBC mode with a 32-byte key (256 bits) very quickly. Its purpose is to provide a more secure alternative to passworded .zip files or giving the user the chance to store or send a file via the Internet in reasonable security.
CAKE (Key Addressed Crypto Encapsulation) is a bunch of Python and C++ for implementing the CAKE protocol. The CAKE protocol is a protocol in which all messages have source and destination addresses that are public keys. This is in the same way that IP packets have a source and destination address that is an IP address.
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.
OpenSignature is a project for the digital signature of documents. It works with all cards supported by OpenSC, and focuses on adding support for cards from accredited Italian CAs. The goal is to provide the first single product capable of supporting cards from multiple vendors/countries. This contrasts the approach taken by card vendors/providers whose software follows an exclusive single-vendor approach. OpenSignature attempts to make a major contribution to interoperability in the digital signature domain, and aims to greatly facilitate the setup of public access points that are currently the objective of several projects in Italy.
Botan is a crypto library written in C++. It provides a variety of cryptographic algorithms, including common ones such as AES, MD5, SHA, HMAC, RSA, Diffie-Hellman, DSA, and ECDSA, as well as many others that are more obscure or specialized. It also offers SSL/TLS (client and server), X.509v3 certificates and CRLs, and PKCS #10 certificate requests. A message processing system that uses a filter/pipeline metaphor allows for many common cryptographic tasks to be completed with just a few lines of code. Assembly and SIMD optimizations for common CPUs offers speedups for critical algorithms like AES and SHA-1.
Dar is a shell command that makes backup of a directory tree and files. Its features include splitting archives over several files, DVD, CD, ZIP, or floppies, compression, full or differential backups, strong encryption, proper saving and restoration of hard links, extended attributes, file forks, Door inodes, and sparse files, remote backup using pipes and external commands (such as ssh), and rearrangement of the "slices" of an existing archive. It can run commands between slices, before and after saving some defined files or directories (for a proper database backup, for example), and quickly retrieve individual files from differential and full backups. Several external GUIs exist as alternatives to its CLI interface, like kdar, DarGUI, SaraB, etc.