HASH 2X

Name: Hash 2X Author: Bxsciencer (aka Jason Lee) Download: Hash2x.zip Compatibility: Parent page not set File Size: 1356 bytes

This is a multivariable hash function that I created. Its pretty fast (especially on a computer), and can have outputs of any size greater than 8 (any less is ridiculously insecure, although a simple edit to the program will allow for any output size greater than 0). However, due to the limitations of the 83/84, 256 is the max inputs and outputs for the moment. The outputs are stored in Str1, so they can be recalled. There has been no editing of anything except for the files included in this download. PS. Any help in analyzing this algorithm is most welcome and greatly appreciated.

What the community thinks:

Second preimage attack

Aumasson 07 Nov 2008 12:34

Dear Jason,

Have found a method to find second preimages for HASH 2X. It exploits the fact that two digits with the same integer value modulo 154 will produce the same value of "password" after the loop

    for x in range(3):
        password[0] += password[len(password) - 1]
        temp_num = 0
        for i in range(len(password)):
            password[i] += temp_num
            temp_num = password[i]
        password = [(j % mod_list[x]) for j in password]

The code below, if put in the main program of the Python program in Hash2x.zip, can be used to find second preimages instantaneously, for any digest length.

# second preimage attack

    length = int(raw_input("Digest bitsize: "))                
    m1 = raw_input("First message: ")    
    m2 = [unichr( ord(i)+154 ) for i in m1]

    hash1 = candidate(m1, length)
    hash2 = candidate(m2, length)

    print "\nhash(",m1,")="
    print hash1

    print "\nhash( ",
    for i in m2: print "\b%s" % (i),
    print ")="
    print hash2,"\n"

    if ( hash1 == hash2 ):
        print "Collision"
    else:
        print "No collision"

Best,
JP

Last edited on 07 Nov 2008 12:38 by Aumasson Show more

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