Easy to follow description of the equihash algorithm

[str4d]

See also my answer here:

Calculate solutionSize

An Equihash instance has two parameters: (n, k). An Equihash solution is a list of numbers of length 2k. For Zcash’s current Equihash parameters (200, 9) that means a solution is a list of 512 numbers. Now, if we stored those directly in the solution header, we’d need to pick a “size of number” that fitted all possible values for these numbers. A reasonable guess might be a standard 32-bit number (4 bytes long). However, that would have made the solution stored in the block header 2048 bytes, c…