This isn’t how Sha works
Here, there's 91.7 bits of entropy in what goes into the hash function. Each guess shaves off more than 10 bits of entropy. After 9 guesses, only one password conforming to the generation format will be possible... yes, it will be very (impractically) hard to find this password, but the rest could be done offline to find the 10th value and solve it in 10 guesses.
e.g. Make 9 random guesses.
Then, for each of the 2^92 possible input strings:
1. Hash it.
2. See if the hash matches the things we know about the hash from the previous guesses.
You can do this in 9 online guesses with feedback + a very large number of offline guesses, and have the solution for the 10th.
The information is there-- just the best search strategies known are very expensive.
Right, the entire search space of random passwords.
The matching hash characters are tongue-in-cheek. They don't help you. They could've just given you the entire hash up front and you would still have to search the entire random password space. Sure, you could do it "offline", but it would still take forever to compute
It would be only be possible if the password length was below a certain threshold (maybe 30 characters) beyond that limit, there wouldn't be enough atoms in the known universe in order to store every hash/password combination.... making it physically impossible....
That is-- out of the range of current brute force, but if it were just a few characters shorter, it could be attacked with this oracle technique no problem.
If they give you the hash upfront (or this oracle), you can test passwords offline without using up a limited number of guesses. It may be very computationally expensive to brute force the space, but the information is there.
If they don't, you get 10 guesses, and you have effectively no chance of guessing the password.
> It may be very computationally expensive to brute force the space, but the information is there.
If the password is long enough, it will take longer than the heat death of the universe to brute force the space. So in practice, brute forcing secure passwords might as well be impossible.
Well, no-- I'm saying that if you have 9 guesses, you can get enough of the hash that you can eliminate all of the passwords but 1.
> If the password is long enough, it will take longer than the heat death of the universe to brute force the space. So in practice, brute forcing secure passwords might as well be impossible.
Here, the password has 88-90 bits of entropy. Out of reach to brute force, but just a few characters shorter and it wouldn't be. And, of course, if there's weaknesses in the hash function ever found, it may be able to elide some or all of this search process.