Tcpcrypt

Tcpcrypt is a protocol that attempts to encrypt (almost) all of your network traffic. Unlike other security mechanisms, Tcpcrypt works out of the box: it requires no configuration, no changes to applications, and your network connections will continue to work even if the remote end does not support Tcpcrypt, in which case connections will gracefully fall back to standard clear-text TCP.
Platform：Windows/Linux/FreeBSD/MacOS；License： New BSD License (BSD-2-Clause)
Reference：https://github.com/sorbo/tcpcrypt

Thep

Thep project aims to provide homomorphic encryption libraries to developers so they can in turn create privacy and confidentiality aware software. Currently the code implements the Paillier cryptosystem in Java, along with it's homomorphic operations and key generation. Saving/transporting keys and encrypted integers can be accomplished using methods inherited from Serializable.
Platform：Java；License： GNU Lesser General Public License v3 (LGPL-3.0)
Reference：https://code.google.com/p/thep/

Paillier

Paillier is a very basic pure Python implementation of the Paillier Homomorphic Cryptosystem. The idea of homomorphic computation is to encrypt some numbers, perform algebraic operations like "add" and "multiply" on cyphertexts, then decrypt the result and find it to be exactly the same as if corresponding "+" and "*" operations were applied to the plaintexts. In other words, a homomorphic cryptosystem enables cryptographically secure computations in an untrusted environment.
Platform：Python；License： GNU General Public License v3 (GPL-3.0)
Reference： https://github.com/mikeivanov/paillier

Pccipher

Pccipher is the ProgClub encryption software. That's the software that allows you to encrypt and decrypt data in PHP and Javascript. It's compatible with 32-bit and 64-bit implementations of PHP, and should work in any Javascript capable web-browser.
Platform：Windows/Linux；License：MIT License or GNU General Public License v2 (GPL-2.0)
Reference：https://www.progclub.org/wiki/Pccipher

Sqlcipher

SQLite Cipher is an SQLite extension that provides transparent 256 bit AES encryption of database files. Pages are encrypted before being written to disk and are decrypted when read back. Encryption is provided by the OpenSSL crypto library.
Platform：Windows/Linux/FreeBSD/MacOS；License： BSD-3-Clause
Reference：https://github.com/sjlombardo/sqlcipher

Gibberish-AES

A fully OpenSSL compliant javascript library for AES encryption. It only supports CBC AES encryption mode, and it's built to be compatible with one of the most popular AES libraries available, OpenSSL. It also passed the FIPS certification from NIST.
Platform: Windows/Linux/FreeBSD/MacOS；License: MIT License
Reference: https://github.com/mdp/gibberish-aes

FBEncryptor

FBEncryptor is enabled to encrypt/decrypt a message. Supported encryption algorithm is AES 256 bit only. Additionally BASE64 encode/decode is supported.
Platform: MacOS；License: MIT License
Reference: https://github.com/dev5tec/FBEncryptor

GnuPG

GnuPG is the GNU project's complete and free implementation of the OpenPGP standard as defined by RFC4880 . GnuPG allows to encrypt and sign your data and communication, features a versatile key managment system as well as access modules for all kind of public key directories. GnuPG, also known as GPG, is a command line tool with features for easy integration with other applications. A wealth of frontend applications and libraries are available. Version 2 of GnuPG also provides support for S/MIME.

GnuPG is Free Software (meaning that it respects your freedom). It can be freely used, modified and distributed under the terms of the GNU General Public License .

effm

Encryption for Flash Memory. Supports: Encryption and Decryption / Hardware design / Filesystem tuning / User interface design. The main purpose is to protect text/data/images/video/audio fileformat in flash memory. This program is license under Apache License 2.0.

vcrypt

VCrypt is a small tool to encrypt and decrypt Folders. This project is a small and Java based tool that will allow you to easily encrypt and decrypt folders on your operating system. This program is license under Artistic License/GPL.

keyonzip

KeyOnZip is built upon the well-known open source software 7-Zip, by adding a new archive format .koz for supporting the smart key management KeyOnDemand service from the Kodsun system. The service of KeyOnDemand is free, which uses the standard XMPP technologies to provide the free, reliable and confidential digital key management and instant messaging services to 3rd parties. KeyOnZip is developed in C++ and currently running on Windows XP/NT/2000/2003/Vista in English, Simplified and Traditional Chinese.

encryptit

The piece of software when hosted on google app engine it will store the sensitive information in encrypted format (which is encrypted using blowfish.) One should login using google account before performing encryption or decryption after logging in user selected operation will be performed. This program is license under GNU General Public License v3 (GPLv3).

emount

eMount is a free system administrator tool for Linux that can mount, encrypt and manage disk image files and physical disk drives. It relies on cryptsetup, which implements the LUKS disk encryption specification. Supports all ciphers and hash algorithms provided by the operating system. This program is license under GNU General Public License (GPL).

duplicity

Duplicity backs directories by producing encrypted tar-format volumes and uploading them to a remote or local file server. Because duplicity uses librsync, the incremental archives are space efficient and only record the parts of files that have changed since the last backup. Because duplicity uses GnuPG to encrypt and/or sign these archives, they will be safe from spying and/or modification by the server.

The duplicity package also includes the rdiffdir utility. Rdiffdir is an extension of librsync's rdiff to directories---it can be used to produce signatures and deltas of directories as well as regular files. These signatures and deltas are in GNU tar format.

Bcrypt

Bcrypt is a lightweight blowfish file encryption utility which aims for cross-platform portability of not only the actual code, but the encrypted files as well. In addition to providing 448-bit encryption, bcrypt overwrites input files with random garbage. This program is license under BSD License.

Npk

File packing library with zip compression & tea encryption. Npk's features: C library / Store many files into one file / Support compression with zlib / Support encryption with tea / Header encryption / Platform independent. (linux/mac/windows) / Support command-line tool / Multithread safety. (windows only, yet) / Unit test with CMake / Minimal build option for read-only usages.

Aarni

Aarni is a small and easy-to-use file encryptor. It's based on Qt 4. Currently, AES-128 in the XTS mode (approved as the IEEE 1619 Standard) is used to encrypt data. SHA-384 is used to generate the encryption key and the initial tweak value from the password inputed by the user. All files are compressed before encryption. NOTE If you forget the password you use, the only way I know to decrypt the file is to crack it by brutal force. So, be careful.

Portable Encryption

Poratable file encryption. Portable file encryption utility, can be run from removable storage and leaves no trace on the computer it was run on. Source is pure python. Option to use either BLOWFISH or XTEA for encryption. This program is license under GNU General Public License v3.

Naranja

Naranja is mainly to build Linux systems that use the Padlock Hardware Encryption engine of VIA EPIA motherboards. Project Naranja uses the Padlock Security Engine of VIA EPIA mini-ITX motherboards in order to provide a toolkit that will let end-users easily set up and use encrypted filesystems with Linux. This program is license under GNU General Public License v2.