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1  Bitcoin / Hardware wallets / Re: 19 out of 24 words of BIP39 passphrase (brute-force last 5?) on: April 29, 2019, 10:53:53 PM
Quote from: Lucius on April 29, 2019, 09:59:43 AM
Quote from: JGoodwin10 on April 29, 2019, 01:32:50 AM
I guess I would have to wait for hardware to get significantly better for it to be feasible. Maybe in 10 years time Tongue I guess it's the ultimate HODL.
Is there any chance that you find the lost words without brute-force them? I know you say that you lost them, but are you sure they are irretrievably lost or you can not find them right now? If you do not mind to share where / how you store this backup? Maybe somebody can help you with advice, and may also help someone else to not make the same mistake.



They are irretrievably lost. The details are not important.
2  Bitcoin / Hardware wallets / Re: 19 out of 24 words of BIP39 passphrase (brute-force last 5?) on: April 29, 2019, 01:32:50 AM
Quote from: HCP on April 29, 2019, 12:41:47 AM
I think the original calcuation of "1.4x10^14 combinations" is probably about right.

As the OP correctly identified a large percentage of combinations are invalid, because the mnemonic checksum will fail before you even get as far as calculating keys. That is to say, for a given set of 23 words... it seems that only around 8 (3 bits) out of the 2048 words in the BIP39 word list will actually be a "valid" 24th word.

The 'btcrecover' script can probably be leveraged as a starting point... although from memory I think it will only find up to 2 or 3 missing words at the most. If OP is sure that they have the first 19 words and needs to "only" find the final 5... well, it'll still take a "long" time. 3 missing words and I would have said you might have been "OK"... 4 and you'd be looking at a time measured in months if not years.

I dug up my old hacky script (find_missing_seed_word.py) that allows you to specify the words you know and put an 'x' in for missing words. On my system it seems to be able to "find" valid seeds (not even generating keys etc) at a rate of around 1,000,000 in 7-8 minutes... Granted, it probably isn't the most optimised script (it has file writes for logging etc) as my python skills are pretty poor, but it should be "ballpark"

Given the total possible number of valid seeds to find when missing 5 words is around 1.4*10^14... I think it'll take "quite a while"[1] at that rate to go through all the valid seeds Tongue



[1] Some rough maths suggests that will be something like ~1864 years. Undecided

Thanks for the insightful response. I guess I would have to wait for hardware to get significantly better for it to be feasible. Maybe in 10 years time Tongue I guess it's the ultimate HODL.
3  Bitcoin / Hardware wallets / Re: 19 out of 24 words of BIP39 passphrase (brute-force last 5?) on: April 27, 2019, 07:41:16 PM
Quote from: Lucius on April 27, 2019, 04:50:10 PM
JGoodwin10, just for info, are you the same person who asked this question 2 years ago?

I know that some users manage to find / brute force one or two missing words from seed, but I am not sure is it possible to get 5 missing words. Maybe fact that you know the exact sequence of words and that you have your public address can make the job easier, but you should wait for answer from a technically experienced user (HCP).

Did you try to do anything with : https://github.com/gurnec/btcrecover

No I am not. This individual seems to have had only 5 words, whereas I have 19 words and I am missing 5. I haven't tried btcrecover yet since based on the math I've done, it doesn't seem like a feasible option.

It would be great if a technically experienced user could provide some insight. Do you have any suggestions for who would be a good person for this?
4  Bitcoin / Hardware wallets / Re: 19 out of 24 words of BIP39 passphrase (brute-force last 5?) on: April 27, 2019, 01:29:31 PM
Quote from: gt_addict on April 26, 2019, 08:54:48 PM
Quote from: JGoodwin10 on April 26, 2019, 08:31:13 PM
Quote from: NotFuzzyWarm on April 26, 2019, 08:16:23 PM
Quote
Is there any hardware out there designed for this? I am aware of ASICs that compute sha-256 hashes but not sha-512 hashes.
Perhaps I could tweak one to work with sha-512 since they are very similar.
No tweaks are possible with an ASIC-based miner because the SHA256D algo is hard coded into the chips and cannot be changed.

Oh and fyi these days 'typical' ASIC-based BTC miners run well over 13THs and the latest run over 70THs.

Thanks very much for the info. Do you know if there are any ASICs that compute SHA512 hashes?
Good to know typical miners run so fast! I wonder how these chips are designed and if one could be 3d-printed.

You want to 3d print a silicon chip?Huh  Roll Eyes Cheesy
Just looking for a solution, whatever that may be Cheesy
5  Bitcoin / Hardware wallets / Re: 19 out of 24 words of BIP39 passphrase (brute-force last 5?) on: April 26, 2019, 08:31:13 PM
Quote from: NotFuzzyWarm on April 26, 2019, 08:16:23 PM
Quote
Is there any hardware out there designed for this? I am aware of ASICs that compute sha-256 hashes but not sha-512 hashes.
Perhaps I could tweak one to work with sha-512 since they are very similar.
No tweaks are possible with an ASIC-based miner because the SHA256D algo is hard coded into the chips and cannot be changed.

Oh and fyi these days 'typical' ASIC-based BTC miners run well over 13THs and the latest run over 70THs.

Thanks very much for the info. Do you know if there are any ASICs that compute SHA512 hashes?
Good to know typical miners run so fast! I wonder how these chips are designed and if one could be 3d-printed.
6  Bitcoin / Hardware wallets / 19 out of 24 words of BIP39 passphrase (brute-force last 5?) on: April 26, 2019, 07:53:36 PM
I have managed to lose 5 words of my 24 word Ledger Nano S recovery phrase. I have words 1-19 but I am missing words 20-24.
I have significant holdings on the wallet so would very much like to recover it if possible.
The passphrase is a BIP39 mnemonic (see https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki).
I have the bitcoin and ethereum public addresses for this mnemonic. I am wondering if it's feasible to brute force the passphrase.

Each word is 11 bits (2^11 = 2048 possible words).
The last (24th) word of the passphrase is of the following form [3 random bits][8 bit checksum].
Therefore I only have to check 2^(55 - Cool = 2^47 = 1.4x10^14 combinations.
I would have to compute SHA-512-HMAC with an iteration count of 2048.
As far as I understand, that means I'd have to compute 1.4*10^14 * 2048 = 2.87*10^17 hashes in total.

Is there any hardware out there designed for this? I am aware of ASICs that compute sha-256 hashes but not sha-512 hashes.
Perhaps I could tweak one to work with sha-512 since they are very similar.

Assuming a fairly typical ASIC hashrate of 1TH/s (10^12 hashes per second), I could exhaust the search space in 2.87*10^5 = 287000 seconds = 3.3 days. I'd probably get there sooner, of course (expected 1.65 days). Time is not something I am worried about. Even if I have to wait months, I don't mind - so if I can get 10GH/s at a reasonable price, that would be great.

I would really appreciate any help/information you could provide to help me out and make sure I haven't missed anything.
I could also use GPUs for this (I calculate I can run them at roughly $1/10TH/s - so it would cost me $28.7k to exhaust the search space, which I will do if there are no cheaper options).

Many thanks,
James
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