nCrypted Cloud!

[TrueCrypt is not exactly "Open Source", but the source is available. See the reviews to get more information.]

Cryptomator provides transparent, client-side encryption for your cloud. Protect your documents from unauthorized access. Cryptomator is free and open source software, so you can rest assured there are no backdoors.

GnuPG allows to encrypt and sign your data and communication, features a versatile key management system as well as access modules for all kinds of public key directories. GnuPG, also known as GPG, is a command line tool with features for easy integration with other applications. A wealth of frontend applications and libraries are available. Version 2 of GnuPG also provides support for S/MIME.

odrive is a free application that makes it easy to manage, access, and share all of your files from one place. Integration into more than 20 services, full bi-directional desktop sync, placeholder files, a robust web client, and advanced sharing capabilities.

AxCrypt is a simple file encryption software for Windows. It integrates seamlessly with your workflow to encrypt, decrypt, store, send and work with files.

AES Crypt is an advanced file encryption utility that integrates with the Windows shell or runs from the Linux command prompt to provide a simple, yet powerful, tool for encrypting files using the Advanced Encryption Standard (AES). A Java library is also available for developers using Java to read and write AES formatted files.

Disk Utility is the name of a utility created by Apple for performing disk-related tasks in Mac OS X. These tasks include:

Boxcryptor is an easy-to-use encryption software optimized for the cloud. It allows the secure use of cloud storage services without sacrificing comfort. Boxcryptor supports all major cloud storage providers (such as Dropbox, Google Drive, Microsoft OneDrive, SugarSync) and supports all the clouds that use the WebDAV standard (such as Cubby, Strato HiDrive, and ownCloud). With Boxcryptor your files go protected to your cloud provider and you can enjoy peace of mind knowing that your information cannot fall into the wrong hands. »

No encryption of dynamic disks, but command-line-encryption! Dynamic disks must be converted to basic disks with EasyUS Partition Master or Partition Guru before encrypting with Bitlocker. Windows BitLocker & "Bitlocker To Go" Drive Encryption is a data protection feature in Windows 10 Professional, Windows Vista Enterprise and Windows Vista Ultimate for client computers and in Windows Server 2008. BitLocker protects against data theft or exposure on computers that are lost or stolen, and offers more secure data deletion when computers are decommissioned. Bitlocker To Go (BTG) is essentially Bitlocker for external drives. It’s full volume encryption for all your USB drives: http://blogs.msdn.com/b/rockyh/archive/2009/03/01/bitlocker-to-go.aspx »

CryptSync is a small utility that synchronizes two folders while encrypting the contents in one folder. That means one of the two folders has all files unencrypted (the files you work with) and the other folder has all the files encrypted.

LibreCrypt (formerly DoxBox) is an open-source disk encryption for Windows and the successor of FreeOTFE

DiskCryptor is the only truly free solution, provided under GNU General Public License (GPLv3), which offers encryption of all disk partitions, including the system partition. The main criteria for open-source software is the availability of its source code under one of the open source licenses. The only open-source alternative to DiskCryptor that has comparable features is TrueCrypt. However, because of the restrictive license under which TrueCrypt is provided — the TrueCrypt Collective License — TrueCrypt cannot be classified as a truly free software, as it places limits on the use and modification of its source code by developers. There are other alternatives with similar functionality, but they are fully proprietary ones, which makes them unacceptable to use for protection of confidential data. »

GPG for Mailis an open source plugin for Apple Mail. Encrypt, decrypt, sign and verify mails using OpenPGP with a few simple clicks.

Pismo File Mount Audit Package is an application that allows users to mount the contents of ZIP, ISO, Compact ISO, Compact File Set and Private Folder files to the file system as virtual folders.Pismo File Mount Audit Package is available free of charge for personal and business use

If your computer were ever to be stolen, are you certain that your personal information cannot be discovered? Jetico’s BestCrypt software automatically encrypts your files so that nobody can read the data unless they have the right password or keys.