Windows demo program for de-crypting files inside Cryptomator vaults
This demo application is provided to illustrate how C# can be used to decrypt Crytomator-encrypted vaults.
It provides only one-at-a-time single-file decryption, although a Windows-form front-end is provided which will render a tree-view of the vault to make file selection simple. Encryption of plaintext files is not supported, and access to Cryptomator vaults is read-only. No modifications are made either to the Cryptomator files nor the vault file structure.
I am not part of the official Cryptomator development team and this project is not supported or sanctioned by the team. Use this program at your own risk.
.Net 4.6.1 on compatible Windows systems. This program was not intended for, and will not run on other operating systems.
The project uses several NuGet packages, all of which are MIT-licensed or are public-domain:
- Miscreant 0.3.3
- Json.Net
- RFC3394
- SCrypt 2.0.0.2
...and a variety of Microsoft .Net packages that are dependencies because the Miscreant library targets .Net Standard 1.3
This program supports version 6-8 vaults, including vaults maintained by current Cryptomator releases (which add a dirid.c9r recovery file to each folder).
Note: format 8 vaults using the SIV_GCM cipher combo (the default for vaults newly created by Cryptomator 1.6 and later) are not supported. Vaults upgraded from earlier formats retain the supported SIV_CTRMAC cipher combo.
This demo application and related source code are licensed under GPLv3 unless otherwise noted.
7/13/2026 (v1.3) - Fixed vault passwords containing non-ASCII characters (now encoded as UTF-8, matching the Cryptomator reference implementation). Fixed a crash when browsing vaults maintained by Cryptomator 1.6.9+, which write a dirid.c9r recovery file into every folder; unrecognized or undecryptable entries (e.g. sync conflict copies) are now skipped instead of aborting the listing. Updated NuGet dependencies to address security advisories.
4/1/2022 - Added support for version 8 vaults.
9/11/2020 - Added Explore Encrypted File right-click context menu option. This will open a Windows file explorer at the encrypted file location. This can facilitate restoring previous versions of the encrypted file in some cases (for example, when the vault is stored on Microsoft OneDrive). Restore previous versions with caution and at your own risk.