Steghide - Steghide is a steganography program that is able to hide data in various kinds of image- and...
VeraCrypt - VeraCrypt is a free open source disk encryption software for Windows, Mac OSX and Linux.
DeepSound - DeepSound is the way of hiding your message in an audio file.
Windows BitLocker - This topic provides a high-level overview of BitLocker, including a list of system requirements, practical applications, and deprecated features.
OpenPuff - OpenPuff is a professional steganography tool: HW seeded random number generator (CSPRNG)
Knox - Knox offers easy disk image encryption and comes with a built-in backup service.