JHasher
freeware checksum calculator
OVERVIEW
JHasher is a freeware Java-based checksum calculator, which allows you to calculate a file checksum. Checksums, also called hash sums, are used to check if a file has been modified, either accidentally (transmission errors, bad storage media) or intentionally (by third parties).
It has been designed for being user-friendly and quick to use. There is also an advanced command-line mode available for performing checksums over multiple files or folders.
Currently supported checksums are MD5, SHA-1 and CRC-32. Read the support section to know more about future checksum support.
INSTALLATION
JHasher is programmed in Java, and hence is a portable application which requires no installation. You can copy it to any folder or removable drive.
SYSTEM REQUIREMENTS AND COMPATIBILITY
The only requirement is to have the Java Runtime Environment (JRE) installed in your computer. JHasher runs in any Java-enabled Operative System.
You can download the last version of Java SE JRE from this page: http://www.oracle.com/technetwork/java/javase/downloads/index.html#need
USING JHASHER IN GRAPHICAL MODE
Start the application. From File menu, select the checksum type. JHasher will calculate the value and the result will be shown in a message, and also logged in the output field.
The process may take a while, depending on the file size and the data transfer speed of the media.
You can repeat this operation for additional files. If you want to work with large sets of files or folders, you may be interested in the more advanced command line mode.
NOTE: If you don't want to check the result against any value, or this value is unknow, just ignore the “check against” field and the clipboad content related messages. Otherwise go ahead to the next section.
CHECKING AGAINST CLIPBOARD CONTENT
Tipically, you would like to check the resulting checksum against a known value. With JHasher you can do it in just 3 steps:
1- Before starting JHasher, copy the expected checksum to the clipboard.
2- Start JHasher. You should now see the clipboard content in the “check against” field.
3- Now select the checksum type and the target file. The result message will inform you about whether the calculated checksum matches the clipboard content or not.
NOTE: If you want to keep processing aditional files in the same session, you will have to manually paste the text on the “check against” field. Automatic clipboard detection only works for the first file, because this application is designed mainly for “one-shot” usage, in order to keep the GUI as simple as possible.
COMMAND LINE MODE (ADVANCED)
With the command-line mode, it is possible to calculate checksums over a list of files or a folder. When passing a folder URL, JHasher will calculate checksums for every file contained in the folder, but this operation is not recursive (e.g.: if there is a nested folder inside the target directory, it will be skipped).
To use the command-line mode, open a terminal in the same directory where JHasher.jar is stored. Then use the following syntax:
java -jar JHasher.jar [checksum] [mode] [list of URLs]
where:
[checksum]: One of the currently supported checksum algorithms. As of December 2010, they are:
“-md5”
“-sha-1”
“-crc32”
[mode]: There are two modes
“-files”: Checksum over a file or list of files
“-dir”: Checksum over each file contained in a folder (non recursive)
[list of URLs]:
Using -files option: this will be a single file URL (or a list of them separated by blankspaces)
Using -dir option: Only a single directory URL is allowed.
URLs can be full qualified (e.g.: C:\My folder\subfolder\filename.extension) or relative to the same folder where JHasher.jar file is stored (e.g.: filename.extension). Depending of your OS, you will be required to specify the file extensions, and the separator character (\) may be different. Also take into account that the files or folders should be readable (permissions).
Example calls:
For a single file (called file1.txt): java -jar JHasher.jar -md5 -files file1.txt
The same but for a list of files: java -jar JHasher.jar -md5 -files file1.txt file2.txt file3.txt
Files in a folder (called my folder): java -jar JHasher.jar -md5 -dir myfolder
Or outside the JHasher directory: java -jar JHasher.jar -md5 -dir C:\parent_folder_1\parent_folder_2\myfolder
LICENSE
JHasher is a freeware application. You are free to use it as many time as you want, without any charge. Check the details in the EULA.txt file inside the zip package.
SUPPORT AND FUTURE RELEASES
This utility has been developed only for academical purposes. It is a practical application of the Model View Controller (MVC) approach, and as result of this, the code is well prepared for extensibility an modification. If you want a certain checksum algorithm to be included in future releases, or you want to report a bug, or just give your opinion, send a mail to jhasherproject@gmail.com.
The project would go open-source in the future if a considerable ammount of people is interested on the source code.
JHasher v1.0 (2010)