When I set my first BTC wallet in 2011 I was basically illiterate in computer things. The wallet software told me to create a very hard password, which I did, I thought of a very long password, however memorable -- and I remember it to this day.

I thought my bitcoins were safe because I had remembered that long password (I have probably written it on paper somewhere also), just to discover, 2 years later, that it was worthless without the wallet file that hold my private key, which was washed down the toiled after a Windows breakdown followed by a full computer format (the default solution to all things Windows).

Why didn't the wallet software let me know I had to take care of that single file remains a mistery to me. Why did it put so much focus on the hardness of that password, that would only protect my wallet from my family and my dogs, is beyond my imagination.

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Ok, in fact I imagine the password was used to somehow encrypt my secret key so viruses of all kinds wouldn't be able to read it. I, despite being illiterate, understood more of computer things than anybody nearby and had at that time the only Windows computer without a virus in the whole town, probably, so maybe the software should have been clearer to me.

I would prefer to memorize or store my secret key in paper, thank you, than to keep a vulnerable file on my computer, or to memorize a worthless password.

Electrum lets you do this. You create a seed of about 10 words. Write them down and you can delete the wallet. I tested this. The issue in 10 years time might be that the original wallet source is lost so at least keep a copy of the exe.

What prevents you from running away with the money? There isn't a contact page with real people on it, nor a registered business in the background, I suppose?

We cannot walk away with the mony, because we never have access to the full funds. We let the users send a partial wallet only containing the bits needed to check if we have bruteforced the wallet. But without the actual private keys. So therefor we cannot scam our clients. There is a real registered company behind it. USW bvba. We exists already for 5 year HQ Brussels, mostly in creating software solutions. As we did have the knowledge about Bitcoins, we wanted to help lessen the sad stories of Bitcoins (e.g. we have lost our Bitcoins)

This would require me to submit known passwords around the time i lost my wallet and details of the variations i use.

I'll need a week to reset every other password i use first.

You are correct. That is also something I tell the clients before they are providing the passwords. That they should make sure that all their passwords are changed. Even so, never reuse your password for Bitcoins as they are too valuable.

Cool idea. HN readers are probably not your target audience, but I’m sure there are lots of non-tech-savvy bitcoin owners who could be.

Good point, but you never know. Also first pitching to tech savvy people. As we try to reduce the scammy part (not a lot of business really trying to recover the coins for the customer). Thus any advice is welcome ;)

There is a free tool to do this on your own without trusting anyone else:

https://github.com/peterjkrey/bitcoin_recover

Definitely helpfull as other tools. But this recovers the secret key only if you didn't add a password to your wallet. Also we provide a service, because not everybody knows the inner workings of Bitcoin. Luckily we have a lot of these tools for tech savvy people. We also pledge to send Bitcoins to the third party tools that we use while recovering!

I presume part of the advantage of a services they have a lot of compute power (or Asics?) to throw at the task.

This very vaguely reminds me of the rainbowcrack services back in the day!

"Thus we created mechanism of extracting the information we need from the wallet to verify the password, but without actually sending the full wallet. "

how this part works, can you explain?

In you wallet, not all addresses have budget. But they are still encrypted. So we can check the decryption phase with parts of the wallet that have no coins.

Sorry but it doesn't make sense:

You are getting a percentage, 15%

- how you will know how much BTC I have, only thing I am giving you is one empty address, no?

That part is based on trust. Most clients are happy enough that we have recovered their funds and are also doing their end of the deal. If there are to much clients not doing their end, then we will have to scratch the partial wallet deal. But at the moment we didn't have any client rejecting the fee.

Wishing you good luck, sounds like totally legit, even trusting service, I will refer in the future for sure.