VeraCrypt

Creates a virtual encrypted disk within a file and mounts it as a real disk. Encrypts an entire partition or storage device such as USB flash drive or hard drive. Encrypts a partition or drive where Windows is installed (pre-boot authentication). Encryption is automatic, real-time(on-the-fly) and transparent. Parallelization and pipelining allow data to be read and written as fast as if the drive was not encrypted. Encryption can be hardware-accelerated on modern processors. Provides plausible deniability, in case an adversary forces you to reveal the password: Hidden volume (steganography) and hidden operating system.