Right now there are thousands of computers connected to the Internet, dutifully calculating SHA-256 hashes and sending their results to other peers on the Bitcoin network. There’s a tremendous amount of computing power in this network, but [Ken] is doing it with a pencil and paper. Doing the math by hand isn’t exactly hard, but it does take an extraordinary amount of time; [Ken] can calculate about two-thirds of a hash per day.

The SHA-256 hash function used for Bitcoin isn’t really that hard to work out by hand.Â The problem, though, is that it takes a 64 byte value, sends it through an algorithm, and repeats that sixty-four times. There are a few 32-bit additions, but the rest of the work is just choosing the majority value in a set of three bits, rotating bits, and performing a mod 2.

Completing one round of a SHA-256 hash took [Ken] sixteen minutes and forty-five seconds. There are sixty-four steps in calculating the hash, this means a single hash would take about 18 hours to complete. Since Bitcoin uses a double SHA-256 algorithm, doing the calculations on a complete bitcoin block and submitting them to the network manually would take the better part of two days. If you’re only doing this as your daily 9-5, this is an entire weeks worth of work.

Just for fun, [Ken] tried to figure out how energy-efficient the bitcoin mining rig stored in his skull is. He can’t live on electricity, but donuts are a cheap source of calories, at about $0.23 per 200 kcalories. Assuming a metabolic rate of 1500 kcal/day, this means his energy cost is about 67 quadrillion times that of an ASIC miner.

Video below.

Inefficient perhaps, but at least Dixon actually delivers their pencils.

#butterflylabs

Not only that, but you don’t submit each hash you calculate, you only submit hashes that have enough leading zeros. The chance that a hash would have only one leading (hex) zero is 1/16. Currently mined blocks have 16 leading hex zeros, that’ one hash in 2^64 hashes. (mining pools accept somewhat more common hashes for partial credit)

but unlike a computer, [Ken] will feel a bit sad (or hungry) if the hash comes out to 0xDEADBEEF

Sudoku Is a game of numbers that increases happieness when completeing…….

Too bad he can’t use GPGPU acceleration. Image and pattern recognition take a lot more processing power than simple math, and the brain can do that instinctively.

Funny this article and the one about CCN are conected ,http://cs.brown.edu/people/anna/papers/ltt04.pdf I Googled CNN and hash page 3 of the pdf contains this statement “Graph-Based Authentication. Graph-based authentication [12, 19, 22, 27] generalizes the idea of amortizing a signature over a hash chain in such a way as to tolerate packet losses.” HMMMMMMM very interesting HACKADAY

So his cost is 67 quadrillion times that of a bit coin mining machine? Would he be cheaper if we sent him to China?

Not exactly, his energy consumption, while higher, is only 6-7 times that of a computer. He’s just a ton slower!

interesting..great post.

Cough Mentat /Cough.

See Dune series.

-A

So mining “by hand” should be worth more :-)

The real question is – can he run Crysis?

Probably not Crysis, but Doom or Unreal for sure. :)

Best Hackaday comment ever!

Bit coin is contributing to the heat death of the universe!

everything is contributing to the heat death of the universe

maybe its just me but reminds me of this

https://www.youtube.com/watch?v=0Whn0YzNG4s

:P