Need Help Recovering Lost Part of My BIP39 Seed Phrase

[goldkingcoiner]

Hi everyone,

I’m in need of help and not sure where to ask.

The problem is that I lost part of my BIP39 seed phrase. I have the following words:

1, 2, 3, 7, 8, 9

However, I’m missing words 4, 5, 6, and 10, 11, 12.

I’ve done some research to understand how BIP39 seeds work. I know there are 2048 possible words in the wordlist, so recovering 6 missing words would result in
204
8
6
2048
6
  possible combinations, which is infeasible. But I still have hope because the last word in a BIP39 phrase is derived from the previous ones, meaning in theory, only 5 words are truly lost.

Additionally, I’ve read that the seed phrase must match a checksum, which greatly reduces the possibilities.

The main asset I had is in Ethereum (ETH), and I still have the ETH address linked to the wallet, which could help narrow things down. However, I lack the technical expertise to code custom tools or use GPU-based or distributed computing for a brute-force attack.

Given that there’s over $25 million USD in this wallet, I have a considerable budget to potentially recover the seed, and I’m willing to pay for the necessary computational resources or a solution.

Before investing heavily in brute-forcing the missing words, I want to first see if there’s any feasible way to recover the seed using computational power.

If anyone has a good solution, I’m offering a generous reward.

Thank you!

That is 2048^6 different combinations you would have to try to brute force. I consider that practically unfeasible for realistic brute force, but technically possible, on paper. I probably would not waste my time and money on cracking it, but perhaps you get extremely lucky?

[Cricktor]

That is 2048^6 different combinations you would have to try to brute force.

No, the search space is only 1/16 of what you write and that answer has already been given in this thread. Twelve mnemonic recovery words represent 128 bits of entropy and 4 bits of partial SHA-256 checksum. Therefore OP's search space is 2⁶² and not 2048⁶. You don't have 2048 choices for the last word, only 128 are actually valid to give a correct checksum.

Still not feasible because to find the correct private key you have to perform 2048 PBKDF2 rounds and further derivation of private keys to check for a match for every sample in the entropy search space.

I wonder how the split recovery words got lost and if there isn't by any means another copy or backup?