taCrypt is an application to encrypt, decrypt and wipe files. It runs on Android, but also provides a version that runs on a Java VM.
taCrypt
What is taCrypt?
Getting started
Define the salt
Modify the script
Java application
Debugging
Legal issues
1. Introduction
taCrypt (in the following termed "the APP") is an application to encrypt, decrypt and wipe files. It runs on Android, but also provides a version that runs on a Java VM.
The APP has following features:
- Runs on Android and Java VM (1.6 or higher)
- Encryption and decryption of files with AES-128
- Secure erasing of files by overwriting them before deletion
- Crypto code (BeanShell script) is open source and can be modified by the user
- The APP detects unauthorized modification of the BeanShell script
- The Android version supports the VIEW Intent for any file type
There is a free and a PRO version of this APP. The free version has all functionality of the PRO version but only supports files with a maximum size of 50 KB. It is therefore only a demo to try the (PRO) APP.
2. Getting started
Before you use the APP for the first time, you should define the encryption salt. This makes the encryption of your files stronger.
If you access the storage card of your Android handy from your desktop PC, then you should export the Java application to the storage card. This will allow you to decrypt your encrypted files from your desktop PC.
3. Define the salt
The encryption salt is a static text which is hashed together with the password to create the AES key. This augments the quality of the key.
If you define a salt, make sure you always remember it! Should the salt get lost (e.g. because you deinstall and reinstall the APP) and you don't know it anymore, you will not be able to decrypt your already encrypted files anymore!
4. Modify the script
The real work of the APP is done by a BeanShell script. It is not necessary that you modify the script, but you can if you want. The script can only be changed from the Android APP which will then saveguard it from modification from outside the APP. An upate of the APP will never overwrite an existing script.
If you change the script, keep following points in mind:
- The modification of the script can result in the inability to decrypt already encrypted files!
- In the editor you can always load the default script by clicking on 'Load default'.
- Make a backup of the script by exporting the Java application. The script will then be exported along with the application.
5. Java Application
The Android APP also contains a version which runs on a Java VM ≥1.6. You can export the Java version to the storage card of your Android device. The Java application, the BeanShell script and some other files are stored in the subdirectory taCrypt of your chosen target directory.
The Java version can be started as follows:
java -jar taCrypt.jar
6. Debugging
If you have problems with the APP, you can set the Log Level in the APP settings to analyse them. If you define a value higher than NONE, the APP will log informationen to the logcat. The highest amount of information is written with log level VERBOSE.
7. Legal issues
Thank you for choosing this SOFTWARE! You may only use this SOFTWARE if you agree with the conditions listed further below:
COPYRIGHT
This SOFTWARE has been developed by Tanapro GmbH, www.tanapro.ch, (in the following termed AUTHOR). All rights reserved.
NO WARRANTY
The SOFTWARE is provided AS IS without a warranty of any kind. All express, implied or statutory warranties, including any implied warranty of merchantibility or fitness for a particular purpose, are hereby excluded. The AUTHOR does not warrant that the SOFTWARE is fail-safe or error-free. The user must bear all risks when using the SOFTWARE.
NO LIABILITY
In no event will the AUTHOR be liable for direct, indirect or consequential damages related to the use (or the inability of the use) of the SOFTWARE, even if the AUTHOR has been advised of the possibility of such damages.