Home Screenshots Video License Download Roadmap Feedback Donate Share Feature-Requests DE

Welcome to the official CrococryptMirror Homepage:
Encrypted File Backups

CrococryptMirror is a free software without registration, without activation, without limitations and without ads.


File and Folder encryption software CrococryptMirror 1.4 released - New password features and stability improvements

Added on 01/10/2017 by Frank Hissen

HissenIT released a new version of the file and folder encryption tool CrococryptMirror. It includes a password change function and - as requested by many users - a command-line option to provide the keyfile password. Although not recommended, this function can be used to provide the password, e.g., in scripts for automation purposes. The feature can also be used to "store" the keyfile password. continue

News: CrococryptMirror 1.2 released – 32bit support and bugfixes

Added on 01/18/2016 by Frank Hissen

We released an update of CrococryptMirror as version 1.2. This relates to the setup and the portable version. Beside some bugfixes, we added a 32bit version for Windows XP and above. continue

News: CrococryptMirror and CrococryptFile ready for Windows 10

Added on 07/31/2015 by Frank Hissen

We were able to test CrococryptMirror and CrococryptFile on Windows 10 successfully. Both applications run without problems in their respective current versions. continue


CrococryptMirror (aka "Crococrypt") is an encryption tool which mirrors complete folders to encrypted folders. The encryption algorithms that are used are AES and Twofish (256 bits, cascading). The keyfile is secured by a password using PKCS #5 (PBKDF2) with a SHA512/Whirlpool based HMAC using 100000 iterations and also AES and Twofish.

Additionally, a ZIP compression for storage space optimization is used. For reasons of performance the synchronization of source and destination folder is done in the background.

A backup copy of the keyfiles has to be stored at a secure place. Without the keyfile the containers cannot be decrypted.

In the portable version of CrococryptMirror keyfile and settings are stored together with the application folder. Hence, the complete application can be transported on an external storage device. Moreover, the folder "container" can be used to store portable containers.

Mirroring can be done manually (on-demand) or by using the sync service which detects directory changes on the fly.


Use Cases

Some use case and feature examples:

Encrypted Cloud backup

Mirroring of folders on your computer into your cloud storage folder in encrypted form.

Encrypted backup on USB drive

Mirroring of folders on your computer to an external storage device in encrypted form.

Encrypted multi-backup

Multiple storage locations can be used in parallel, e.g., an USB drive, Cloud storage and a local NAS. When using the sync service all encryption destinations while be queued and processed sequentially.

Two encryption modes

Use the automatic sync service or mirror a directory on-demand simply by clicking on CrococryptMirror's tray icon. Use the latter if you work constantly on a certain directory and do not want to create to much load for a backup.

Synchronizing means that also deleted files will be deleted in the container's destination, at the end both directories have the same content. The source directory is not touched.

Two decryption modes

A complete directory can be efficiently decrypted in a bulk operation. When only single files shall be restored, the Explorer view can be used. For this purpose, a local WebDav view on the encrypted container is opened (read-only), so files can be browsed and copied.

Technical Background

For technology enthusiasts, we want to describe some implementation details. CrococryptMirror uses two well-known cryptography providers: Oracle (originally Sun) for AES and Bouncy Castle (open source) for Twofish. These are popular implementations, the cryptography is done using these providers not by implementing the algorithms myself. On computers with CPUs which include AES hardware support, this AES implementation is used automatically. This is also done by other popular encryption tools today.

By using two different encryption algorithms and different implementations, the risk of compromising the whole encryption scheme is minimized. For instance, if you store an archive of your personal data in a cloud storage for a very long time, it might happen that weaknesses in the algorithms itself come up or that security vulnerabilities in the implementations are discovered.

The iteration count of 100000 used for the password protection of the keyfile is upwards compatible with future versions and is not hard coded, for maximum flexibility.


(click to enlarge)



This software is provided 'as-is', without any express or implied warranties or conditions of any kind.
In no event will the author be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, subject to the following restriction: You may not distribute or redistribute this software without permission.

Official Download

CrococryptMirror is available in English and German. All languages are included in a single installer.

Current AV Warnings

From time to time products of the Crococrypt Product Family are detected by individual antivirus software products as malware. These messages are so called "false positives". In such cases, you receive a warning by mistake because some binary pattern in the heuristics database of your antivirus software matches some random pattern in our product.

You can always verify that it is indeed a false warning by using, e.g., VirusTotal to scan our website or software. Sometimes even the whole website might be listed as malicious by SINGLE services.

If you are affected by such a case, please inform us via e-mail. We have and will correspond with the respective AV manufacturer which usually updates its virus pattern database.

The are no known warnings at the moment.

Downloads for Windows (Freeware)

All Windows versions since XP and above are being supported.

CrococryptMirror 1.4
Setup, 64Bit
CrococryptMirror Portable 1.4
Self-extracting, 64Bit

CrococryptMirror 1.4
Setup, 32Bit
CrococryptMirror Portable 1.4
Self-extracting, 32Bit

General Information

Version History

1.4 (01/10/2017):

1.3 (02/22/2016):

1.2i (02/10/2016):

1.2 (01/18/2016):

1.1 (07/20/2015):

1.0 (03/26/2015):

0.9b (02/26/2015):


These are simply feature "ideas", there is no plan or schedule to implement them.

Idea backlog


For suggestions, bug reports or other requests simply write me an e-mail to crococrypt@frankhissen.de or use our anonymous feature request form at the bottom of this page.


Donate / Support

CrococryptMirror is freeware. Nevertheless, if you like to support the project's further development financially:

Support with

The payment is done via PayPal using HTTPS (separate window). In case you want to support the development of CrococryptMirror in a different way, simply contact me.


If you like CrococryptMirror, it would be a great thing if you share it with others!

e-Mail Facebook Twitter Google+ Pinterest LinkedIn
reddit Digg StumbleUpon XING



Post your request