Title:       ReHash
Author:      Dominik Reichl 
Email:       dominik.reichl@t-online.de
Environment: VC++ 5.0-7.0, NT 4.0, Win95/98/ME, Win2k, WinXP
Keywords:    Hash, Security, Cryptography, Win32
Level:       Intermediate"
Description: 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.
Section      Cpp
SubSection   Cryptography

ReHash screenshot


Contents


Introduction

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:

Algorithm
Standard
Inventor
Hash Digest Size
CRC-16    
16 bits
CRC-16-CCITT    
16 bits
CRC-32 ANSI X3.66, FIPS PUB 71  
32 bits
FCS-16    
16 bits
FCS-32    
32 bits
GHash (GHash-32-3, GHash-32-5) - -
32 bits
GOST-Hash R 34.11-94  
256 bits
HAVAL (5 passes, 256 bits)   Zheng, Pieprzyk,
Seberry
256 bits
MD2 RFC 1319 Rivest
128 bits
MD4 RFC 1320 Rivest
128 bits
MD5 RFC 1321 Rivest
128 bits
SHA-1 FIPS PUB 180-1 NIST/NSA
160 bits
SHA-2 (SHA256/SHA384/SHA512)   NIST/NSA
256/384/512 bits
SizeHash-32 - -
32 bits
Tiger   Anderson, Biham
192 bits


Usage

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:

Option
Description
-help / -h / -?/
-version / -v		 Print some information about ReHash.
-fullpath / -f Output the full paths of hashed files.
-nopath Just output the filenames of hashed files, not the full paths to the files.
-rcrsv / -recur / -r Recursive scanning. Scan all files in the specified path including files in subdirectories.
-norcrsv / -norecur Disable recursive scanning. Scan only the files in the specified path not including subdirectories.
-all / -a Enable all algorithms.
-none / -n Disable all algorithms.
-crc16 / -nocrc16 Enable/disable the CRC-16 algorithm.
-crc16c / -nocrc16c Enable/disable the CRC-16-CCITT algorithm.
-crc32 / -nocrc32 Enable/disable the CRC-32 algorithm.
-fcs16 / -nofcs16 Enable/disable the FCS-16 algorithm.
-fcs32 / -nofcs32 Enable/disable the FCS-32 algorithm.
-ghash3 / -noghash3 Enable/disable the GHash-3 algorithm.
-ghash5 / -noghash5 Enable/disable the GHash-5 algorithm.
-gost / -nogost Enable/disable the GOST-Hash algorithm.
-haval / -nohaval Enable/disable the HAVAL-5-256 algorithm.
-md2 / -nomd2 Enable/disable the MD2 algorithm.
-md4 / -nomd4 Enable/disable the MD4 algorithm.
-md5 / -nomd5 Enable/disable the MD5 algorithm.
-sha1 / -nosha1 Enable/disable the SHA-1 algorithm.
-sha256 / -nosha256 Enable/disable the SHA-256 algorithm.
-sha384 / -nosha384 Enable/disable the SHA-384 algorithm.
-sha512 / -nosha512 Enable/disable the SHA-512 algorithm.
-size32 / -nosize32 Enable/disable the Size-32 algorithm (simply the byte-count of the message).
-tiger / -notiger Enable/disable the TIGER algorithm.


Thanks / acknowledgements

Thanks to (no particular order):

History