129 lines
3.2 KiB
Python
129 lines
3.2 KiB
Python
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try:
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shathree = __import__('sha3')
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except:
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shathree = __import__('python_sha3')
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import random
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import time
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def sha3(x):
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return decode_int(shathree.sha3_256(x).digest()) #
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def decode_int(s):
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o = 0
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for i in range(len(s)):
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o = o * 256 + ord(s[i])
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return o
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def encode_int(x):
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o = ''
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for _ in range(32):
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o = chr(x % 256) + o
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x //= 256
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return o
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P = 2**256 - 4294968273
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def produce_dag(params, seed):
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o = [sha3(seed)]
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init = o[0]
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picker = 1
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for i in range(1, params["n"]):
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x = 0
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picker = (picker * init) % P
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curpicker = picker
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for j in range(params["k"]):
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x |= o[curpicker % i]
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curpicker >>= 10
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o.append((x * x) % P) # use any "hash function" here
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return o
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def quick_calc(params, seed, pos):
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init = sha3(seed)
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known = {0: init}
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def calc(p):
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if p not in known:
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picker = pow(init, p, P)
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x = 0
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for j in range(params["k"]):
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x |= calc(picker % p)
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picker >>= 10
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known[p] = (x * x) % P
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return known[p]
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o = calc(pos)
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print 'Calculated pos %d with %d accesses' % (pos, len(known))
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return o
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def hashimoto(daggerset, params, header, nonce):
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rand = sha3(header+encode_int(nonce))
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mix = 0
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for i in range(40):
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shifted_A = rand >> i
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dag = daggerset[shifted_A % params["numdags"]]
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mix ^= dag[(shifted_A // params["numdags"]) % params["n"]]
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return mix ^ rand
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def get_daggerset(params, block):
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if block.number == 0:
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return [produce_dag(params, i) for i in range(params["numdags"])]
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elif block.number % params["epochtime"]:
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return get_daggerset(block.parent)
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else:
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o = get_daggerset(block.parent)
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o[sha3(block.parent.nonce) % params["numdags"]] = \
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produce_dag(params, sha3(block.parent.nonce))
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return o
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def mine(daggerset, params, header):
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nonce = random.randrange(2**50)
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orignonce = nonce
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origtime = time.time()
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while 1:
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h = hashimoto(daggerset, params, header, nonce)
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if h <= 2**256 / params["diff"]:
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noncediff = nonce - orignonce
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timediff = time.time() - origtime
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print 'Found nonce: %d, tested %d nonces in %f seconds (%f per sec)' % \
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(nonce, noncediff, timediff, noncediff / timediff)
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return nonce
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nonce += 1
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def verify(daggerset, params, header, nonce):
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return hashimoto(daggerset, params, header, nonce) \
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<= 2**256 / params["diff"]
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def light_hashimoto(seedset, params, header, nonce):
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rand = sha3(header+encode_int(nonce))
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mix = 0
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for i in range(40):
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shifted_A = rand >> i
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seed = seedset[shifted_A % params["numdags"]]
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# can further optimize with cross-round memoization
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mix ^= quick_calc(params, seed,
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(shifted_A // params["numdags"]) % params["n"])
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return mix ^ rand
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def light_verify(seedset, params, header, nonce):
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return light_hashimoto(seedset, params, header, nonce) \
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<= 2**256 / params["diff"]
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params = {
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"numdags": 40,
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"n": 250000,
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"diff": 2**14,
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"epochtime": 100,
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"k": 3
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}
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