class Ethereum::EthashRuby::Hashimoto

Public Instance Methods

calc_dataset_item(cache, i) click to toggle source
# File lib/ethereum/ethash_ruby/hashimoto.rb, line 44
def calc_dataset_item(cache, i)
  n = cache.size
  r = HASH_BYTES / WORD_BYTES

  mix = cache[i % n].dup
  mix[0] ^= i
  mix = keccak512 mix

  DATASET_PARENTS.times do |j|
    cache_index = fnv(i ^ j, mix[j % r])
    mix = mix.zip(cache[cache_index % n]).map {|(v1,v2)| fnv(v1, v2) }
  end

  keccak512(mix)
end
fnv(v1, v2) click to toggle source
# File lib/ethereum/ethash_ruby/hashimoto.rb, line 60
def fnv(v1, v2)
  (v1 * FNV_PRIME ^ v2) % Constant::TT32
end
get_full_size(block_number) click to toggle source
# File lib/ethereum/ethash_ruby/hashimoto.rb, line 64
def get_full_size(block_number)
  sz = DATASET_BYTES_INIT + DATASET_BYTES_GROWTH * (block_number / EPOCH_LENGTH)
  sz -= MIX_BYTES
  sz -= 2 * MIX_BYTES while !Prime.prime?(sz / MIX_BYTES)
  sz
end
light(block_number, cache, header, nonce) click to toggle source
# File lib/ethereum/ethash_ruby/hashimoto.rb, line 10
def light(block_number, cache, header, nonce)
  run header, nonce, get_full_size(block_number) do |x|
    calc_dataset_item(cache, x)
  end
end
run(header, nonce, full_size, &dataset_lookup) click to toggle source
# File lib/ethereum/ethash_ruby/hashimoto.rb, line 16
def run(header, nonce, full_size, &dataset_lookup)
  n = full_size / HASH_BYTES
  w = MIX_BYTES / WORD_BYTES
  mixhashes = MIX_BYTES / HASH_BYTES

  s = keccak512(header + nonce.reverse)

  mix = []
  mixhashes.times { mix.concat s }

  ACCESSES.times do |i|
    p = fnv(i ^ s[0], mix[i % w]) % (n / mixhashes) * mixhashes

    newdata = []
    mixhashes.times {|j| newdata.concat dataset_lookup.call(p + j) }
    mix = mix.zip(newdata).map {|(a,b)| fnv(a, b) }
  end

  cmix = []
  (mix.size / WORD_BYTES).times do |i|
    i *= WORD_BYTES
    cmix.push fnv(fnv(fnv(mix[i], mix[i+1]), mix[i+2]), mix[i+3])
  end

  { mixhash: serialize_hash(cmix),
    result: serialize_hash(keccak256(s + cmix)) }
end