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File Syncing based on JFileSync with encryption and compression for local folders and WebDAV backends. Also (partly) compatible with encfs / boxcryptor (classic) volumes.

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Java based encrypting File Syncing Tool

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File syncing with optional compression and encryption for local and WebDAV folders. For local folders encryption can use EncFS and thus be compatible with encfs4win, BoxCryptor Classic, Encdroid and so on.

JFileSync3 comes with a GUI, command line tooling, and stored profiles.

Find more on the scenarios where this tool might help you in in the growing project wiki. Recently a little bit of discussion started in the issues area at GitHub so feel free to add your comments there.

This software was developed because I personally needed an easy to use syncing tool to have everyday backups - without the need of multiple versions in file history - of highly confidential material - business and private.

None of the services I came accross could suit these needs.

The second reason why I find it helpful is, that I very much rely on online-syncing tools for everyday backups and felt forced to use more than one of these services.

Using too many of them slows down your local machine too much, so I identified a set of backup areas which didn’t need online syncing but just regular cloud based backup. Some of the syncing services available provide WebDAV backends, so I can decide to use a service online or manual (scheduled).

JFileSync3 is heavily based on the work of Jens Heidrich and his JFileSync2.2. After some hacking aroung in his code I felt that this one here is a fork, ripping out his original remote backends and changing the purpose of the tool quite a lot.

I had to realise the Jens re-started his work on the original product, so that this decision now would need some rethinking. Be aware that this code here is based on the 2007 version JFileSync2.2 and not the more recent 2.3 and 2.4 work, which heads in part in similar directions as my code (ripping out the server, using VFS, presenting a new Windows and even Mac integration). I did a manual back sync with 2.3a recently.

JFileSync is a SourceForge project and available via the following URL:

Don’t mix the derived work here and Jens’ clean software on sourceforge. Only bother him if it’s related to his original version. Other complaints go here :-) Feel free to add any issues to this project here.

Other contributions - though not directly committed by him - are from Thanks so much for the fruitfull discussions.

Online Scenario

You replaced (or want to) your regular backups with online syncing tools and don’t have backup media anymore. This helps doing backups of your work in remote situations where e.g. don’t want to carry confidential backup media with you.

Possible Solutions:

a) Trust the providers

Select any of them - I have some personal notes on the in the wiki.

b) Trust the providers encryption

Use Teamdrive, or iDrive Sync. With Teamdrive you can - in some cases - even see the encrypted files depending on the backend you use. With iDrive Sync you have to provide a custom password as a base for the generated keys (This rips out some functions like sharing which gives you a hint, that they really do what they are saying).

c) Encrypt locally on every file access and thus only sync encrypted stuff which you can still see.

Boxcryptor, EncFS come into my mind. Disadvantage here is the de- and encryption on nearly every access. Really locally stored are only the encrypted files.

d) If you trust your local system and need to store frequently accessed files, you would like to encrypt only short before or on backing up/syncing files.

This is where this software fills the gap. It can sync directories, local or WebDAV, and it can do this with either of these encrypted. Additionally it can sync with encfs volumes stored in local folders. It is my common practice, that the local encrypted folders are in turn synced with one of the online syncing services.

If you use EncFS in this scenario, it is possible to access the encrypted and synced files from mobile devices with Boxcryptor Classic for iOS and Android and additionally EncFS tools for android. Also this EncFS solution is compatible with encfs4win and of course Linux based encfs.


Installation and Application Start

Unzip the distribution file to a directory of your choice.

You can start the application through

ATTENTION: Because JFileSync3 is distributed as a Zip archive, Unix users will have to give executable rights manually before launching the application, e.g.: ‘chmod a+rx bin/JFileSync3’.

Nearly all functions of JFileSync3 can be controlled via the Graphical User Interface (GUI). However, JFileSync3 provides full access to all features (apart from plug-ins) via the command line interface. Call bin/JFileSync3 -help to get an overview of all possible command line options.


JFileSync3 works with profiles controlling which folders to use, which files to include or ommit, how to log into WebDAV servers, and which encryption cipher and passphrase to use.

These profiles need to be set up and can be stored in XML files. The distribution contains a set of profile file examples illustrating all the intended scenarios.

License and Usage Terms

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA, 02110-1301, USA

JFileSync3 uses libraries or parts of Open Source projects. Some of them had to be included as source code for technical reasons in their distribution:

Some code in LZMA SDK is based on public domain code from other developers: 1) PPMd var.H (2001): Dmitry Shkarin 2) SHA-256: Wei Dai (Crypto++ library)

You can find a copy all licenses of JFileSync3 and the used libraries in the legal/ directory of this distribution.

Development Notes

Required packages for JFileSync3 development (not included in the distribution):

Used and as a result recommended development tools:

The following structure describes all directories and files included in the JFileSync3 source repository:

The encryption backend tries its very best to avoid known plaintext attacks with filenames like in directory names (src/main/java) and with the contents of the files.

The contents are compressed before they are encrypted (in most cases - depending on size and special file types) and the software tries three algorithms to do that - LZMS, BZIP2, Deflate - in parallel.

The filenames are encoded, scrambled and then encrypted.

Metafiles to speed up access of the directory structures don’t have constant names but calculated ones.

Passwords to derive keys from are not constant along the whole directory structure.

For oldish Java 8 setups you will need the unlimited encryption add-on by Oracle for your JDK, if you want to use anything except the default cipher AES.

Feel free to issue bug reports and ideas here.

Building and Packaging

Building requires a launch4j installation available from the path.

The software is built with the usual

./gradlew build

and can be started - e.g. for IDE integration - through

./gradlew run

Take the ZIP file from build/distributions.

A small test-suite can be found in profiles/test (which is not packaged in the distribtions zip) and can be called via

./gradlew encryptionTest