VeraCrypt
Open source disk encryption with strong security for the Paranoid
...All released files are PGP signed with key ID=0x680D16DE, available on key servers and downloadable at https://www.idrix.fr/VeraCrypt/VeraCrypt_PGP_public_key.asc
VeraCrypt can mount TrueCrypt volumes. It also can convert them to VeraCrypt format.
Documentation: https://www.veracrypt.fr/en/Documentation.html
FAQ : https://www.veracrypt.fr/en/FAQ.html