Quote from: str4wm4n on September 04, 2013, 05:05:41 PM

I am offering a 1btc bounty for someone who can demonstrate a repeatable method for calculating a private key using only paper pencil and brain

What an easy challenge for a huge bounty, I really should hang out on this forum more. A user just gained about $140 for teaching people how to throw dice.

Quote from: Sothh on September 04, 2013, 05:47:46 PM

You could also buy a 16 sided dice or something and use 0-F which would be more proper. If you do it this way, the max address you can use is FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFE BAAE DCE6 AF48 A03B BFD2 5E8C D036 4141

Just pedantry here, but there's no such thing as a fair 16 sided die. Fair dice can only be made from platonic solids.
http://upload.wikimedia.org/wikipedia/commons/c/c7/BluePlatonicDice.jpg

The idea I had to use the full range of bits would be to throw an 8-sided die and write down the private key in octal format. Each throw gives you 3 bits of randomness so to get 256 bits you need to throw 86 times.

Also, instead of throwing two 6-sided dice you could throw a single 12-sided dodecahedron.

Also, you could throw a 4-sided die and a 12-sided die, together giving you up any number in the range 0-F.

Or you could just flip a coin 256 times.

But generating a private key is the easy part. More interesting is generating the corresponding public key. If I'm not mistake that requires calculating the point multiplication of the private key, I guess it could be done since all the long multiplication and long addition stuff you learn at school still works for hex and octal if you stop thinking in base 10. It would take a couple of weeks I imagine. And you'd want to do it a couple of times to make sure you haven't made a mistake.