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Posted 11 Apr 2003


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ReHash - A console-based hash calculator

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4.43/5 (45 votes)
11 Apr 20033 min read
A console-based hash calculator. Supported algorithms: CRC-16, CRC-16-CCITT, CRC-32, FCS-16, FCS-32, GHash-32-3, GHash-32-5, GOST-Hash, HAVAL-5-256, MD2, MD4, MD5, SHA-1, SHA-256, SHA-384, SHA-512, Tiger.

Sample Image - rehash.jpg



ReHash is a free, open source console-based hash calculator.

You can disable hash algorithms selectively per command-line if you don't need or like them, you can choose if you want to use recursive directory scanning or not.

This tool is ideal for webmasters who wish to provide their users hash values of their (downloadable) files. The complete hashing process can be automated by using a shell/batch script. No additional user interaction is needed (i.e. the program won't ask for anything, it's just using the command-line).

ReHash is distributed under the terms of the GNU General Public License v2.

Supported algorithms

The current version of ReHash supports the following hash algorithms:

Hash Digest Size
16 bits
16 bits
CRC-32ANSI X3.66, FIPS PUB 71 
32 bits
16 bits
32 bits
GHash (GHash-32-3, GHash-32-5)--
32 bits
GOST-HashR 34.11-94 
256 bits
HAVAL (5 passes, 256 bits) Zheng, Pieprzyk,
256 bits
MD2RFC 1319Rivest
128 bits
MD4RFC 1320Rivest
128 bits
MD5RFC 1321Rivest
128 bits
160 bits
256/384/512 bits
32 bits
Tiger Anderson, Biham
192 bits


rehash.exe [options] filespec [> outputfile]

The command-line is parsed from the left to the right. So if you execute ReHash like this:
rehash.exe -all -none *.*
it will output nothing, because you first activate all algorithms and then deactivate them all.

Some usage examples:

Hash all INI files in C:\Windows (including subdirectories) using all hash algorithms:
rehash.exe C:\Windows\*.ini

Hash all INI files in C:\Windows (excluding subdirectories) using all hash algorithms:
rehash.exe -norecur C:\Windows

Hash all BAT files on C:\ (including subdirectories) using only MD5 and SHA-1 (remember command-line is parsed from the left to the right):
rehash.exe -none -md5 -sha1 C:\*.bat

Hash all files in C:\Temp (excluding subdirectories) using only the GOST algorithm:
rehash.exe -norecur -none -gost C:\Temp\*

Hash all ZIP files in C:\homepage (including subdirectories) using only the MD5 algorithm and output the hashes to C:\homepage\downloads\hashes.txt:
rehash.exe -none -md5 C:\homepage\*.zip > C:\homepage\downloads\hashes.txt

All options:

-help / -h / -?/
-version / -v
Print some information about ReHash.
-fullpath / -fOutput the full paths of hashed files.
-nopathJust output the filenames of hashed files, not the full paths to the files.
-rcrsv / -recur / -rRecursive scanning. Scan all files in the specified path including files in subdirectories.
-norcrsv / -norecurDisable recursive scanning. Scan only the files in the specified path not including subdirectories.
-all / -aEnable all algorithms.
-none / -nDisable all algorithms.
-crc16 / -nocrc16Enable/disable the CRC-16 algorithm.
-crc16c / -nocrc16cEnable/disable the CRC-16-CCITT algorithm.
-crc32 / -nocrc32Enable/disable the CRC-32 algorithm.
-fcs16 / -nofcs16Enable/disable the FCS-16 algorithm.
-fcs32 / -nofcs32Enable/disable the FCS-32 algorithm.
-ghash3 / -noghash3Enable/disable the GHash-3 algorithm.
-ghash5 / -noghash5Enable/disable the GHash-5 algorithm.
-gost / -nogostEnable/disable the GOST-Hash algorithm.
-haval / -nohavalEnable/disable the HAVAL-5-256 algorithm.
-md2 / -nomd2Enable/disable the MD2 algorithm.
-md4 / -nomd4Enable/disable the MD4 algorithm.
-md5 / -nomd5Enable/disable the MD5 algorithm.
-sha1 / -nosha1Enable/disable the SHA-1 algorithm.
-sha256 / -nosha256Enable/disable the SHA-256 algorithm.
-sha384 / -nosha384Enable/disable the SHA-384 algorithm.
-sha512 / -nosha512Enable/disable the SHA-512 algorithm.
-size32 / -nosize32Enable/disable the Size-32 algorithm (simply the byte-count of the message).
-tiger / -notigerEnable/disable the TIGER algorithm.

Thanks / acknowledgements

Thanks to (no particular order):
  • Markku-Juhani O. Saarinen - GOST-Hash implementation
  • Yuliang Zheng - HAVAL implementation
  • Wei Dai - implementations of various algorithms
  • Dr Brian Gladman - SHA-1/SHA-2 implementation
  • Tom St Denis - Tiger implementation


  • 12 April 2003 - v1.0
    First public release


This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


About the Author

Dominik Reichl
Software Developer
Dominik started programming in Omikron Basic, a programming language for the good old Atari ST. After this, there was some short period of QBasic programming on the PC, but soon he began learning C++, which is his favorite language up to now.

Today, his programming experience includes C / C++ / [Visual] C++ [MFC], C#/.NET, Java, JavaScript, PHP and HTML and the basics of pure assembler.

He is interested in almost everything that has to do with computing; his special interests are security, cryptography and data compression.

You can find his latest freeware, open source projects and articles on his website:

Comments and Discussions

QuestionThank you Pin
juankre29-Dec-11 12:12
Memberjuankre29-Dec-11 12:12 
Generalsha1 16 bits Pin
wassimznaidi15-May-08 7:35
Memberwassimznaidi15-May-08 7:35 
GeneralSHA-0 Pin
Gelly Mazour24-Feb-08 22:57
MemberGelly Mazour24-Feb-08 22:57 
GeneralNice work! Pin
WillianBR7-Feb-08 4:23
MemberWillianBR7-Feb-08 4:23 
QuestionThanks Pin
gamakanna30-Jan-07 23:34
Membergamakanna30-Jan-07 23:34 
GeneralDoesn't beat crypto++ Pin
haploid30-Nov-06 2:32
Memberhaploid30-Nov-06 2:32 
QuestionMistake in SHA-512 calculation. Pin
patti ashwin17-Nov-06 17:37
Memberpatti ashwin17-Nov-06 17:37 
Questionwhat is the polynomial used in the CRC-16 algorithm? Pin
PauMs2-Oct-06 12:22
MemberPauMs2-Oct-06 12:22 
Generala small bug Pin
Waldermort30-Sep-06 21:47
MemberWaldermort30-Sep-06 21:47 
GeneralThank you so much Pin
calsurferpunk28-Aug-06 5:28
Membercalsurferpunk28-Aug-06 5:28 
GeneralNice work Pin
Hatem Mostafa24-Mar-06 0:08
MemberHatem Mostafa24-Mar-06 0:08 
GeneralRe: Nice work Pin
<marquee>ElNoNo15-Aug-06 4:28
Member<marquee>ElNoNo15-Aug-06 4:28 
Generalhelp maual Crypto++ Pin
Anonymous25-Dec-03 0:23
MemberAnonymous25-Dec-03 0:23 
Generalneed a way to be able to use this in VB 6 Pin
wtyd66612-May-03 6:19
Memberwtyd66612-May-03 6:19 
Generalprova0 Pin
ocean06-May-03 2:04
Memberocean06-May-03 2:04 
GeneralCRC algorithms Pin
Tim Smith13-Apr-03 6:09
MemberTim Smith13-Apr-03 6:09 
GeneralRe: CRC algorithms Pin
jacques_freedom31-Mar-04 22:10
Memberjacques_freedom31-Mar-04 22:10 
GeneralRe: CRC algorithms Pin
Dominik Reichl1-Apr-04 0:19
MemberDominik Reichl1-Apr-04 0:19 
GeneralRe: CRC algorithms Pin
Panic2k324-Jan-05 13:34
MemberPanic2k324-Jan-05 13:34 
Generalcould be cool but... Pin
Jim Crafton13-Apr-03 5:01
MemberJim Crafton13-Apr-03 5:01 
GeneralRe: could be cool but... Pin
Chris Losinger13-Apr-03 6:50
professionalChris Losinger13-Apr-03 6:50 
GeneralRe: could be cool but... Pin
Jim Crafton13-Apr-03 11:05
MemberJim Crafton13-Apr-03 11:05 
GeneralRe: could be cool but... Pin
Tim Smith14-Apr-03 5:11
MemberTim Smith14-Apr-03 5:11 
GeneralUseful... but would like to see a managed code version :-) Pin
Jabes12-Apr-03 5:53
MemberJabes12-Apr-03 5:53 
GeneralRe: Useful... but would like to see a managed code version :-) Pin
darkfader9-Jul-03 8:06
Memberdarkfader9-Jul-03 8:06 

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