encryption tools

• AxCrypt is a free, open source, GNU GPL-licensed encryption tool for Windows that prides itself on being simple, efficient, and easy to use.

It supports 128-bit AES encryption only, offers protection against brute force cracking attempts, and is exceptionally lightweight (less than 1MB.)

• 7-Zip is actually a lightweight file archiver. It's completely free, even for commercial use, supports 256-bit AES encryption, and while the official download is Windows only, there are unofficial builds for Linux and OS X systems as well

• VeraCrypt is a fork of and a successor to TrueCrypt, which ceased development last year.VeraCrypt supports AES (the most commonly used), TwoFish, and Serpent encryption ciphers, supports the creation of hidden, encrypted volumes within other volumes

http://lifehacker.com/five-best-file-encryption-tools-5677725

• AES Crypt

Platforms: Windows, OSX, Linux (Crypt4All Lite for Android is compatible).This very easy to use Java based file encryption program integrates with the OS, providing simple file encryption using the right-click menu button (Windows and Linux, or drag and drop for OSX).

• DiskCryptor

Encryption: AES_256, Twofish and Serpent.DiskCryptor is a full disk encryption program for Windows that allows you to encrypt hard drives (including CD’s USB sticks etc.), or individual partitions, including the ability to encrypt the partition and disk on which Windows is installed.

• EncFS

EncFS creates an encrypted volume, which is typically stored in a cloud storage folder (e.g. Dropbox) for easy cloud synching. This folder can be mounted locally as virtual drive, from where files can be accessed unencrypted, just as if they were files in a regular folder.

• dm-Crypt/LUKS

LUKS (Linux Unified Key Setup) is the standard for Linux hard disk encryption. It is built-in to most Linux distros, and can be used with the dm-crypt subsystem to provide transparent full disk encryption.

• Secrecy

This promising new Android app lets you create password protected vaults in which you can store any kind of file (including local Google Docs). 
https://www.bestvpn.com/blog/10995/6-best-open-source-alternatives-to-truecrypt/