free disk encryption
Download from PortableApps.com
VeraCrypt Portable can run from a cloud folder, external drive, or local folder without installing into Windows. It's even better with the PortableApps.com Platform for easy installs and automatic updates.
VeraCrypt is a free disk encryption software based on TrueCrypt 7.1a. It allows secure encryption of full disks as well as virtual volumes that can be mounted on the fly. VeraCrypt has support for various encryption algorithms (AES, Serpent, TwoFish), keyfiles, security tokens, hotkeys, and more.