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.

Jan 29, 2020 OpenPGP OpenPGP is the most widely used email encryption standard. It is defined by the OpenPGP Working Group of the Internet Engineering Task Force (IETF) as a Proposed Standard in RFC 4880. OpenPGP was originally derived from the PGP software, created by Phil Zimmermann. 3 Best Free Full Disk Encryption Programs - Lifewire Jul 01, 2020 Open Source Key Management Solution - Stack Overflow

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The only open source full boot disk encryption alternative, simple and clean implementation, supports booting from network PXE image Guest • Jan 2017 Disagree Agree; Free Open Source Windows. Encryption Add a feature. 30 Like. Know any more alternatives to Windows BitLocker? Suggest an application to this list

Let's Encrypt - Free SSL/TLS Certificates

Cryptography/Open Source Cryptography - Wikibooks, open Mar 29, 2016 U.S. Export Controls and “Published” Encryption Source Aug 27, 2019 10 Best File and Disk Encryption Tools for Linux