Help needed, I cannot recover my old wallet backup!

[hercula]

Hello everybody!

I hope this is the right place for my post since I'm quite new to the forum.

At the beginning of 2012 I got excited about bitcoins and started mining for a few weeks. My computer wasn't very powerful, so I hadn't the chance to mine many coins before the fan started annoying my wife... so I just stopped, somehow saved my wallet in a usb pen and forgot about the whole thing.

A few days ago I found the old usb key and I'd like to try to recover my coins (about 20-25 BTCs if I recall it correctly). The problem is that I really can’t understand how I exported my wallets (or keys)!!

What I remember is that at the time I was often playing with brainwallets, electrum and multibit, but nothing more..
My backups are four strings, 581 characters long, representing a hex value (ie. there are only characters 0-9, a-f) and all of them start with “80”.

Hopefully somebody will be able to help me.
I’ll be glad to offer 25% if the recovered funds to anyone who can help me retrieve them.

Thanks

[OnkelPaul]

Hex 80 is the start of a private key.
Are you sure about the length 581? Odd lengths would be odd for hex-encoded values
If we assume that the lines contain "compressed" private keys which are 34 bytes long (hex 80 + 32 byte key data + hex 01; you can check whether the 01 is present in that position in each line) and that the lines are actually 580 characters long, then we'd have exactly 256 additional bytes per line. That number is too close to a power of two to be coincidental, but I don't know what data could be represented.

Hope this helps a bit.

Onkel Paul

[dowsey14]

My backups are four strings, 581 characters long, representing a hex value (ie. there are only characters 0-9, a-f) and all of them start with “80”.

Hex 80, as mentioned, is the start of a private key, the character "5"...which begins the private key. You then need to work out where each private key ends, which would be very simple from this point. Simply find the space character (hex 20 I think) or perhaps the null character (hex 00). Each character in that private key is either two numbers, 1 number + 1 character (A to F) or 1 character + 1 number as per hex representation.

When you reach the space character, you've probably got the entire private key which needs to be converted to a string to import into a bitcoin wallet.

[hercula]

Thanks for your suggestions.

I've found roughly ten "80" in the four strings. I then copied the following 64 characters in a hex -> base58check converter to obtain the corresponding wif private key and imported the results into a blockchain.info wallet. All the corresponding addresses are completely empty.

Could these strings be generated from a brainwallet dump or something?
Does somebody know if electrum or multibit generate hex encoded backups?

Probably the answer is just behind the corner, but I tried to find infos online without luck for a few days now!

[Abdussamad]

Thanks for your suggestions.

I've found roughly ten "80" in the four strings. I then copied the following 64 characters in a hex -> base58check converter to obtain the corresponding wif private key and imported the results into a blockchain.info wallet. All the corresponding addresses are completely empty.

Could these strings be generated from a brainwallet dump or something?
Does somebody know if electrum or multibit generate hex encoded backups?

Probably the answer is just behind the corner, but I tried to find infos online without luck for a few days now!

A private key can have two addresses one for the compressed public key and one for the uncompressed public key. Compressed WIF private keys start with L or K while uncompressed ones start with 5. Easy way to get all the possible combos is to enter the private key into bitaddress.org's wallet details tab.

[dowsey14]

I'd check things out before you enter anything into bitaddress.org...but didn't someone mention code there that sends the information to a server? I wouldn't want anyone with my private keys except myself. I wouldn't do anything online with that sort of data, unless it's for like 0.1BTC...but even 1 BTC I wouldn't do it, it's too risky. People will steal 1BTC without any qualms.

You should be able to verify if a private key points to a public key. It should be easy to do so. Just load bitcoin-qt, wait for the blockchain to sync, and use the importprivkey command to import the private key into the client. bitcoin-qt will find the public key for that private key and then proceed to update the balance. It's not that hard.

Don't use online stuff unless it's heavily password protected, and even then I wouldn't even trust it. I've heard too many stories of BTC going AWOL because someone wanted to test something out.

[deepceleron]

Thanks for your suggestions.

I've found roughly ten "80" in the four strings. I then copied the following 64 characters in a hex -> base58check converter to obtain the corresponding wif private key and imported the results into a blockchain.info wallet. All the corresponding addresses are completely empty.

Could these strings be generated from a brainwallet dump or something?
Does somebody know if electrum or multibit generate hex encoded backups?

Probably the answer is just behind the corner, but I tried to find infos online without luck for a few days now!

A private key can have two addresses one for the compressed public key and one for the uncompressed public key. Compressed WIF private keys start with L or K while uncompressed ones start with 5. Easy way to get all the possible combos is to enter the private key into bitaddress.org's wallet details tab.

Compressed public keys were not introduced until Bitcoin 0.6.0, released March 31 2012, and only addresses created by a new install would be compressed; the keypool would still be uncompressed.

You say "my computer wasn't very powerful". You would not have mined 25 BTC in a few weeks in 2012. This would require spending serious money on many GPU mining rigs specifically set up for Bitcoin. At the minimum 2012 difficulty of 1.4M, even a $300 ATI GPU selected specifically for mining use would make you less than 1BTC a week.