Quote from: simplyred on March 06, 2018, 02:00:12 PM

but the thing is i just cant see how it would be easy to find some 3 word in the exact right order. That would be so many possibilities.

Because, as previously explained, the word list is known: https://github.com/bitcoin/bips/blob/master/bip-0039/english.txt

There are only 2048 words in this list... so the total number of combinations is "only": 2048 * 2048 * 2048 = 8,589,934,592 combinations.

While that might look like a large number (and it is, if you're attempting to test them manually), computers are particularly good at doing repetitive things quite fast... a simple python script can generate all of those combinations in a matter of hours (if not minutes)

Additionally, not ALL combinations are actually valid seeds, the last word is a form of "checksum"... so the number of VALID seeds is actually a LOT less than the total number of combinations... for instance, I ran a script I use for finding missing seed words... I stopped it after it had tested a little over 500,000 combinations (in about 3 or 4 minutes)... it had only found 1960 valid combinations.

The real time consuming part is actually converting these seeds to addresses and checking if they have any BTC value (or match a known address)... It would no doubt take days to check all combinations for a match when trying to find the missing 3 words... but it would certainly be doable in a "reasonable" amount of time.

However, if the order/position of the words is not known, the difficulty increases by a significant amount... as the number of combinations that need to be checked increases by orders of magnitude.