# Mining Monero with Pencil and Paper

People have successfully performed SHA-256 hashing with pencil and paper

1. If I wanted to perform the CryptoNight PoW by hand how would I do so?
2. Are there any PoW instructions that a human with a pencil, paper and enough patience could follow? What about with the assistance of a basic hand held calculator?
• Define "by hand" - doing every calculation using only paper and pencil, long form? Or with the help of a digital calculator? Why would anybody waste their time on something like this?
– hyc
Aug 10, 2016 at 17:39
• I think @Susan thinks about doing the same as Ken Shirriff (righto.com/2014/09/mining-bitcoin-with-pencil-and-paper.html) Aug 10, 2016 at 20:25
• CryptoNight is considerably more compute intensive than plain old SHA-256. Multiple rounds of AES, plus 4 other possible hash algorithms.
– hyc
Aug 11, 2016 at 0:57
• @ClementJ. Yes. I saw that exact page and was curious how that would compare with Monero. I will edit my question Aug 11, 2016 at 5:44
• @hyc the answer with and without a digital calculator would interest me. Some people like crossword puzzles and sudoku. I think this would be fun. Aug 11, 2016 at 6:00

I like the question because an answer to it will give a better understanding, from first principles, of the underlying algorithms. So question 1 has two parts:

1a) How does the CryptoNight PoW algorithm work at all?

That's specified here: https://cryptonote.org/cns/cns008.txt

1b) How does it really work, on a low level, looking at elementary instructions?

I'm not familiar enough with the basics of how AES, Keccak and the different hash functions used (blake, groestl, skein) work on a detailed level, but that seems to be the only things that you have to look up.

As for question 2), of course you as a human can perform all the elementary instructions that your computer does when running cryptonight PoW, provided your remaining life span is long enough. You could e.g. attach a debugger while mining monero, look at the elementary machine instructions that are performed, and repeat them by hand. Obviously a hand held calculator will help to do additions, multiplications etc. faster.

I think the overall answer is "it's ridiculously impractical to perform by hand". The Cryptonight hash operates over a 2 megabyte data space, using multiple rounds of AES along with a variety of other cryptographic hash algorithms. What human is going to have the patience to write out 2 million bytes of data even once, let alone multiple times?

I would downvote this question as being utterly ludicrous. Some of it is blindingly obvious:

E.g. "How much harder is hashing CryptoNight by hand compared to hashing SHA-256 by hand?" - The ratio of difficulty for CryptoNight vs SHA-256 is the same, whether calculating by hand or by computer. The difference in amount of computations is the same either way. This is a stupid question.

A valid question would be "where can I find a description of the CryptoNight hash algorithm".

• They probably didn't know it was so difficult. The validity of a question isn't based on what the answer is. Aug 11, 2016 at 15:00
• The question about "how much harder" - the difficulty ratio is the same, whether you're doing it by hand or with a computer. The question as worded is invalid.
– hyc
Aug 11, 2016 at 15:14
• @hyc based on your comments, I edited out the "how much harder" part of my question Aug 13, 2016 at 5:02