Is 128-bit md5 do full mapping for 128-bit binary set?

Question

I'm writing a utility to convert md5 (or sha1) digest to a distinguishable image, something like ssh-keygen -lv. Usually, similar messages can have digests very different, but hackers can modify the message bit by bit to try to get a similar but still different md5 digest to mock the original one. When matching is done by machine, the trick will certainly fail. But when matching is done by human eye, user could be fooled.

To avoid of such trick, the convert program can generate the image from a modified digest as follow:

image = generateImage( md5(md5 + Random_Secret) )

The Random_Secret will reshape the digest, the similarity introduced by hacker will be removed after the transformation.

Now comes the question, since the final md5() take input of another md5 variable, which is only 128-bit length, (here ignore the Random_Secret which is a constant in all) is it safe to generate enough different values for feeding generateImage()?

Question also for other digest algorithms: sha1, etc.

Answer 1

A hash function should have the following properties, among others:

In cryptography, the avalanche effect is the desirable property of cryptographic algorithms, typically block ciphers and cryptographic hash functions, wherein if an input is changed slightly (for example, flipping a single bit), the output changes significantly (e.g., half the output bits flip).

see https://en.wikipedia.org/wiki/Avalanche_effect

Thus, hackers should not be able to slightly modify the message to obtain a similar digest unless the hash function is broken. Also it should not be possible to create a message that results in a specific hash value (so it should resist preimage attacks, see https://en.wikipedia.org/wiki/Preimage_attack).

md5 is cryptographically broken

So would the use of a simple md5 hash already be sufficient?

No. Although md5 is a widely used hash function, it has the problem that it is cryptographically broken and therefore insecure.

One basic requirement of any cryptographic hash function is that it should be computationally infeasible to find two distinct messages that hash to the same value. MD5 fails this requirement catastrophically; such collisions can be found in seconds on an ordinary home computer.

see https://en.wikipedia.org/wiki/MD5

Therefore, it is generally recommended to stop using md5 in a cryptographic context.

Since such a collision would result in the same hash in the first inner hash operation in your approach, the repeated hash with an additional constant random secret would also be the same. This means that this attack can successfully exchange the message or file with a different one.

The other hash algorithm you mentioned, SHA-1, is also cryptographically broken.

In this context, there is a worth reading article from Arstechnica from 2008 about the exploitation of md5 collisions to create bogus CA intermediate certificates.

Example of a hash collision

Finally to illustrate a hash collision, here are two .jpg files with the same md5 hash. The collision was created using the following open source project published on Github: https://github.com/cr-marcstevens/hashclash.

The following small Python program writes the files yes.jpg and no.jpg into the current directory to be able to compare the files visually, and then calculates the md5 hash for them - which results in exactly the same value for both files.

import binascii
import hashlib

yes = b'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'
no = b'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'


def write_file(filename, data):
    with open(filename, 'wb') as f:
        f.write(data)


if __name__ == '__main__':
    yes_data =  binascii.unhexlify(yes)
    write_file("yes.jpg", yes_data)
    no_data = binascii.unhexlify(no)
    write_file("no.jpg", no_data)

    md5_yes = hashlib.md5(yes_data).hexdigest()
    md5_no = hashlib.md5(no_data).hexdigest()
    print("yes.jpg, md5 =", md5_yes)
    print("no.jpg, md5 =", md5_no)