SaluSafe is an encrypted email, chat, and file storage and sharing system. Your email and files are highly encrypted end-to-end, and cannot be intercepted by any third party. It was built from the ground up for security via strong cryptography, and is not just another security wrapper on top of an existing email solution.
PeaZip is a cross-platform file archiver utility that provides a unified portable GUI for many open source technologies like 7-Zip, FreeArc, PAQ, UPX, etc. Creates 7Z, ARC, BZ2, GZ, *PAQ, PEA, QUAD/BALZ, TAR, UPX, WIM, XZ, and ZIP files. It extracts more than 150 archive types: ACE, ARJ, CAB, DMG, ISO, LHA, RAR, UDF, ZIPX, and more. Features of PeaZip include extracting, creating, and converting multiple archives at once, creating self-extracting archives, split/join files, strong encryption with two factor authentication, an encrypted password manager, secure deletion, find duplicate files, calculate hashes, and export job definitions as scripts.
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.
The Open-Transactions project is a collaborative effort to develop a robust, commercial-grade, fully-featured, free-software toolkit implementing a full-strength financial cryptography library, API, CLI, and prototype server. Open-Transactions democratizes financial and monetary actions. You can use it for issuing currencies/stock, paying dividends, creating asset accounts, sending/receiving digital cash, writing/depositing cheques, cashier's cheques, creating basket currencies, trading on markets, scripting custom agreements, recurring payments, escrow, etc. Strong crypto is used. Balances are unchangeable (even by a malicious server). Receipts are destructible and redundant. The transactions are unforgeable. The cash is untraceable. The cheques are non-repudiable.
Moneychanger is a GUI built on top of Open Transactions, a financial crypto library. Moneychanger can be used to create pseudonyms, issue currencies, open accounts, withdraw and deposit cash (untraceable digital cash), write and deposit cheques, trade on markets, and much, much more.
GNUnet is a peer-to-peer framework with focus on providing security. All peer-to-peer messages in the network are confidential and authenticated. The framework provides a transport abstraction layer and can currently encapsulate the network traffic in UDP, TCP, HTTP, HTTPS, or direct 802.11 (WLAN). GNUnet supports accounting to provide contributing nodes with better service. The services built on top of the framework include anonymous file sharing and a virtual network providing IPv4-IPv6 transition via protocol translation over the P2P network.
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.
jEncrypt is a commandline file encryption archiver. Files are encrypted with the AES-CTR mode, which was recommended by the National Institute of Standards and Technology in 2001 (NIST SP 800-38A). AES-CTR mode only provides confidentiality. It requires a message authentication code such as CBC-MAC to ensure an encrypted message is not accidentally modified or maliciously tampered with, which jEncrypt currently does not provide.
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.