Really free software
OSI certified

Multi-Platform support
  • It is platform independent (100 % Java), so you can run it on all common operating systems, such as Windows (95/98/ME/NT/2000/2003/XP/Vista), Linux (Debian, Fedora, Gentoo, JDS, Knoppix, Linspire, Red Hat, Slackware, SUSE, Turbolinux, Mandriva, Ubuntu, etc.), Unix (BSD, HP-UX, Mac OS X/PPC, Mac OS X/x86, Solaris/SPARC, Solaris/x86, etc.) or any other operating system (e.g. OS/2) with a Java Runtime Environment (JRE). Do you want to live with your current operating system for ever?
  • Keeps compatibility with JRE 1.3.1, but takes all the advantages of JRE 1.4.2, JRE 5.0 or JRE 6 if available, runs also on entirely free platforms with latest versions of gij or kaffe
  • Runs on both 32 and 64 bit systems. Yes, Jacksum is 64 bit ready, you just need a 64 bit JRE.
  • It is large file aware, it can process filesizes up to 8 Exabytes (= 8,000,000,000 Gigabytes), presupposed your operating system respectively your file system is large file aware, too.
  • As it has a commandline interface, Jacksum can be used in cronjobs and autostart environments
  • It is aware of special files like FIFOs and symbolic links on Linux/Unix and system folders on Windows
  • Works with the SendTo-feature on many file browsers (e. g. Mac OS X Finder, Microsoft Windows Explorer, Gnome Nautilus, KDE Konqueror, ROX Filer).
General program features
  • Supports 58 popular checksum algorithms including strong one-way-hash algorithms (Adler32, BSD sum, POSIX cksum, Bzip2's CRC-32, CRC-8, CRC-16, CRC-24, CRC-32 (FCS-32), CRC-64, ELF-32, eMule/eDonkey, FCS-16, GOST, HAS-160, HAVAL (3/4/5 passes, 128/160/192/224/256 bits), MD2, MD4, MD5, MPEG-2's CRC-32, RIPEMD-128, RIPEMD-160, RIPEMD-256, RIPEMD-320, SHA-0, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, Tiger-128, Tiger-160, Tiger, Tiger2, Tiger Tree Hash, Tiger2 Tree Hash, Unix System V sum, sum8, sum16, sum24, sum32, Whirlpool-0, Whirlpool-1, Whirlpool and xor8)
  • It can calculate customized CRC algorithms and it also supports the combination of multiple algorithms
  • Fully customized output is supported
  • It can calculate checksums, CRCs and hashes on both files and user input sequences (text, hexadecimal and decimal)
  • The program is mature and very stable
  • Algorithms are very fast (go ahead, and compare Jacksum's performance with similar tools)
  • Recursively file processing is supported (it operates not only on files from a specific directory, but also on files from all subdirectories of the specified directory)
  • It can verify both the content and timestamp of files
  • It helps you to find duplicates by knowing just only the checksum of a file
Compatibility and customizability
  • By default, output is 100% compatible to Unix-standard tools such as sum, cksum, md5sum and sha1sum
  • File output format is flexible and fully customizable (add filesizes to the md5 output, create SFV files, XML data or create lists with the eDonkey-Link format for example)
  • Additionally, the .jacksum file format is supported (it is an open, platform independent and compatible file format, so you will be able to check files and timestamps against a list even after many years and even if you have changed your Operating System!)
  • Multiple Encodings (hex, BASE 16, BASE 32, BASE 64 and BubbleBabble) for all checksums, CRCs and hashes are supported

Growing community

  • Jacksum 1.7.0 has been downloaded more than 30000 times
  • Jacksum has been incorporated in many other free projects
  • The Jacksum project has both a great and active community, it consists of both users and developers, all of them providing bug reports, support and feature requests, Jacksum users have brilliant ideas
Developer support
  • It returns an exit status which is dependent on the result of the calculation/verification process, so you can use Jacksum in scripts or batches
  • Jacksum provides an open API, so you can incorporate Jacksum in your own projects
  • Javadoc can be generated from the sources
  • Ant-script is available which is also ready for use with an IDE such as Netbeans



The Team

The long list of contributors can always be found in the latest download package and in the copyright section. The founder and lead for this project is Johann N. Löfflmann from Germany. Since 2002 he has been working with very talented people all around the world in order to improve Jacksum further.

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