Finding hash less than a target (instead of an exact match)
#1
Hey,
Can hashcat look for a hash that's less than a given value instead of matching a hash?

Example:
Given Target: b169fc6a126d98e2c888859ce0efa3df74186982016772a2ecdd98a7969e44d7
Input: Wordlist/Mask/etc.

Output: find a word whose hash < target, like:
00000000718c60db655b71d8cabb23ca56a68876a00306132159ac5d5bf51fd0
Reply
#2
no this is not possible with hashcat

you assume that the hex hash representation is a number, thats not really the case, of course you could read it as number but thats just because you defined it that way

finding a "lower" hash will be relativ simple tough, just throw some random word at the hashalgo as every output starting with 0-9 or an "a" will be "lower" in your meaning, hex is 0-f so with 0-a you have 11 out of 16 possibilities to get a "lower" hash, in other words, statistically speaking around 70% of your given wordlist should result in a "lower" hash

depending on the algorithm you want to use, your goal can be easily achieved with a small piece of script (python or maybe even as simple as bash)
Reply
#3
(11-01-2022, 02:25 PM)Snoopy Wrote: finding a "lower" hash will be relativ simple tough, just throw some random word at the hashalgo as every output starting with 0-9 or an "a" will be "lower" in your meaning, hex is 0-f so with 0-a you have 11 out of 16 possibilities to get a "lower" hash, in other words, statistically speaking around 70% of your given wordlist should result in a "lower" hash

Unfortunately the target I want to use starts with a few zeroes. The b* hex was just an example. It's more like how proof-of-work works, but my case isn't related to mining.

I was hoping to use hashcat for it's multithread and gpu support mainly. A simple cpu script likely cannot find it in reasonable time.

Thanks for the answer! And sorry about the late reply, I didn't know mybb needed to subscribe to the thread manually for notifications.
Reply