Bitcoin Forum

Dear BTC members,
My friend lost the password for his bitcoin wallet. however many BTC companies offer to help him by sharing wallet.dat file.  I stopped him because of scammers.

My question is, is there a way to help recover his wallet?

please share your thoughts.

Regards

What is the name of the wallet software? Hopefully it's not a custodial wallet.

Does he not have a seed phrase for their wallet? The seed phrase allows for universal funds access even if you lose your wallet file or password.

Nothing but bruteforce which depends on how much he can remember and how strong was the password.
Because wallet.dat passwords aren't saved in any online server nor in his local files, no one can recover it from a database.

If you do not really mean "wallet.dat file" which is for Bitcoin Core or an altcoin fork of it, then the recovery options are based from the wallet.

Assuming either the password is either short or your friend remember parts of the password, brute-force is possible within reasonable time. It comes down whether you choose to,
1. Use your own computer. Least amount of trust is required, but you usually either need to be patient (if you have slow computer) or make big initial investment (if you're willing to buy high end GPU).
2. Use cloud computing service such as vast.ai. Some trust is required, but usually is cheaper for short term usage.
3. Ask for help reputable from service. Few member mention https://www.walletrecoveryservices.com/ (https://www.walletrecoveryservices.com/), but i never try to use this service.

The good thing you did is that you stopped your friend from sharing his wallet.dat with unknown people never trust anyone online with your wallet.dat file there are lots of scammers out there.

I don't know precisely what Crypto wallet your friend is using but you can check the tool from this link below that includes a guide on how to recover your friend's wallet.dat password.

Here's the old one https://github.com/gurnec/btcrecover it only supports a few coins but mainly for BTC
And this is the other one https://github.com/3rdIteration/btcrecover it supports more coins but I don't know if your friend's wallet is supported.

You can also trust walletrecoveryservices.com mention above but I suggest only give the hash of the wallet.dat.

The thing with my friend was 10 years ago. when he started mining and wallet using https://bitcoinknots.org.

his computer was lost and he had the password and words list on it. thus we lost access to his wallet.

I'm not comfortable sharing wallet.dat online and using it on the amazon server.
we knew the password length and what special signs were used. but we have zero experience in how to use any software to crack it down. what kind of high-end GPU is recommended for such a task?


@BitMaxz, how to get HASH of the wallet.dat?


Thank you


 

He might be suggesting to give an encrypted file, which probably won't work....

The problem with all wallet recovering services is that they involve some kind of trust. You are correct in stopping your friend, as there are many scammers around.

walletrecoveryservices don't look to be scammers, but I have never used them as well.

Probably, the best and most secure way is to try to crack it down by yourselves. It might take some time and effort, but if you have a lot of bitcoin, that is probably worth the effort.

By using command-line interface : you can use command line tool such as  sha256sum on Linux or shasum on Mac to obtain the hash of the wallet.dat file.
You can also use checksum calculator that can be downloaded, the software can be used to generate hash from wallet.dat
You can also use online hash calculator.

But you must bear in mind that wallet.dat contains your private keys so better proceed with caution.

You may also try to look at this conversation : https://stackoverflow.com/questions/66869197/what-actually-is-wallet-dat-hash-and-how-does-hashcat-actually-brute-force-the-h

What do you mean by "words list"? Are you referring to a series of 12/24 words that is called seed phrase or mnemonic phrase?
If so, the wallet in question can't be bitcoin core, because it doesn't support seed phrase at all.

Better never share your data with strangers, surely those who come forward will be scammers.  Here in the forum there are people who can help you, such as Babo who has already recovered some doomed wallets.  Or are you sure you don't have the private key stored anywhere?

I guess you could try to bruteforce the password. Just start by installing the bruteforce software and then try to configure it by entering the data that you have (like approximate length, characters it contains etc). It should be pretty straightforward. If you'll face issues with configuration, just ask here and the community will guide you. Good luck with recovering your funds!

First step is to never share his wallet.dat, that was a very good thing of you to not do.
Second step: You have all the time in the world to brute force the password or try to remember it.
IF you can not find it out in the next weeks or month you can try to find a person who can do it, but you should be careful and maybe do it in a public thread on this forum.

There are several very similar services that have a similar name, but the one you are referring to has a good reputation so far and has its own thread on this forum. Of course, the service has its price, but if the OP and his friend can't find a solution on their own, this service might be their best option.

https://bitcointalk.org/index.php?topic=240779.0

Dear gurus,
I've listened to your advice and I will never share a wallet.dat file with anyone.

I've learned a lot of information about Bitcoin, Hash, etc.

But honestly, I Don't know how to use Brute-Force. or other methods more effective. Thus I would like to ask for a mentor or someone who did it in the past and If we will succeed I promise I would consider him/her.

The wallet is with Bitcoinknots, How we could know the type of encryption they are using?
2nd, how to use Brute-Force to recover the password?
3rd, what are the circumstances for using Brute-Force?
4th, If we know the length of the password, for example, 12 characters, how we could start, and where we could finish? how long it takes with a good GPU?
5th, Is there a method for choosing the letters and special signs and symbols to be used to find the password?


We really need expert advices.

regards

If you decide to use software "btcrecover", the author also provide video tutorial on youtube (https://www.youtube.com/playlist?list=PL7rfJxwogDzmd1IanPrmlTg3ewAIq-BZJ (https://www.youtube.com/playlist?list=PL7rfJxwogDzmd1IanPrmlTg3ewAIq-BZJ)) which should give you an idea how to use this tool.


It also depends on which character do you use, which affect total possible password combination. Here's an calculation example with following detail,

• 8 character length.
• The password use lower case (a-z) and number (0-9).
• 1 (One) Nvidia RTX 2080 Ti. Speed data is taken from https://btcrecover.readthedocs.io/en/latest/Usage_Examples/2020-10-06_Multi-GPU_with_vastai/Example_Multi-GPU_with_vastai/#performance (https://btcrecover.readthedocs.io/en/latest/Usage_Examples/2020-10-06_Multi-GPU_with_vastai/Example_Multi-GPU_with_vastai/#performance).

Total unique character used = 26 (lower case)  + 10 (number) = 32 character.
Total possible password combination = 32 character ^ 8 character length = 1099511627776 (about 1.09E12).
Speed of RTX 2080 Ti = 6.4 kP/s or 6400 password per seconds.
1 day in seconds = 60 * 60 * 24 = 86400 seconds.
Brute force time (in days) = 1.09E12 / 6400 / 86400 = ~1971 days.

Unless I'm mistaken, OP friend uses Bitcoin Knots, which is a fork of Bitcoin Core. It is a decentralized wallet where you manage your own coins, I doubt any support will be able to help them recover his password other than suggesting some methods that have been mentioned above.

As far as I understand it, BTCrecover supports variations of Core like Bitcoin Unlimited, XT, etc, so I think you can give it a shot even if Bitcoin Knots is not explicitly mentioned. CMIIW.