Quote from: Abdussamad on March 06, 2014, 05:57:05 AM

Quote from: hercula on March 05, 2014, 08:58:24 PM

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.