Minecraft Java Edition – How to Find SMP Server Seed Based on Known Locations

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Is it possible to find the seed of a 1.4.5 map without having the .dat file by using landmark coords? Is there a program that can come up with a list of possible seeds by entering the coords of dungeon spawners or villages or temples,etc?

Best Answer

No, there is no such program and likely never will be.

As a programming task, it's identical to the least efficient method of password cracking. We can't reverse-calculate the seed no matter how many landmark coordinates we have, because the type of calculation Minecraft uses for seed generation is one-way. Thus, what such a program would have to do is try every seed until it finds one that matches the landmarks.

In computer security terms this is called a brute-force attack, and it can take a very long time:

  1. Minecraft's seeds have 18 quintillion possible values.
  2. A GPU-based password cracker on consumer-grade hardware today, very loosely, can try about a billion numbers a second, given a target result (such as our landmarks).
  3. 1 quintillion is a billion billion.
  4. That gives us about 18 billion seconds needed to try every possible seed.
  5. On average we will have to only try half the seeds, so that brings us down to an average of 9 billion seconds to find a match.
  6. 9 billion seconds is over 285 years.
  7. In reality the program would have to run world-generation (or some kind of faked world generation) on every seed in order to find out if it matches our landmarks, so multiply 285 years by how long it takes Minecraft to start a new world. If we're generous and say a fake-generation takes only 3 seconds, that gives us 856 years to find a match, on average.

And all that is ignoring the question of how the program would handle the fact that our coordinates of landmarks are going to be guesses (which block in a village is the coordinate the world generator got from the seed?) and not exact matches for what the seed actually produced. That adds at least a few processor cycles to every time the program needs to check a particular seed for matches.

So as you can see, the idea is lovely, but in practice finding a seed from landmark coordinates is impractical enough that no-one is going to write such a program – by the time it finishes running, we'd all be dead (and Minecraft will likely have changed its world-generation again…). At least, not practical until we have quantum computers.

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