162 lines
4.9 KiB
Python
162 lines
4.9 KiB
Python
import os
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from binascii import hexlify
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from Crypto.Hash import keccak
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import random
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def to_hex(s):
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return hexlify(s).decode('utf-8')
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memo = {}
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def sha3(x):
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if x not in memo:
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memo[x] = keccak.new(digest_bits=256, data=x).digest()
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return memo[x]
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def hash_to_int(h):
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o = 0
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for c in h:
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o = (o << 8) + c
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return o
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NOTARIES = 40
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BASE_TS_DIFF = 1
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SKIP_TS_DIFF = 6
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SAMPLE = 8
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MIN_SAMPLE = 7
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POWDIFF = 50 * NOTARIES
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SHARDS = 12
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def checkpow(work, nonce):
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# Discrete log PoW, lolz
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# Quadratic nonresidues only
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return pow(work, nonce, 65537) * POWDIFF < 65537 * 2 and pow(nonce, 32768, 65537) == 65536
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class Block():
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def __init__(self, parent, pownonce, ts):
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self.parent_hash = parent.hash if parent else (b'\x00' * 32)
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assert isinstance(self.parent_hash, bytes)
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self.hash = sha3(self.parent_hash + str(pownonce).encode('utf-8'))
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self.ts = ts
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if parent:
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assert checkpow(parent.pownonce, pownonce)
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assert self.ts >= parent.ts
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self.pownonce = pownonce
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self.number = 0 if parent is None else parent.number + 1
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genesis = Block(None, 59049, 0)
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class Node():
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def __init__(self, _id, network, sleepy=False, careless=False, ts=0):
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self.blocks = {
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genesis.hash: genesis
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}
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self.main_chain = [genesis.hash]
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self.timequeue = []
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self.parentqueue = {}
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self.children = {}
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self.ts = ts
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self.id = _id
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self.network = network
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self.used_parents = {}
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self.processed = {}
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self.sleepy = sleepy
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self.careless = careless
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def broadcast(self, x):
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if self.sleepy and self.ts:
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return
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self.network.broadcast(self, x)
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self.on_receive(x)
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def log(self, words, lvl=3, all=False):
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#if "Tick:" != words[:5] or self.id == 0:
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if (self.id == 0 or all) and lvl >= 2:
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print(self.id, words)
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def on_receive(self, obj, reprocess=False):
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if obj.hash in self.processed and not reprocess:
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return
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self.processed[obj.hash] = obj
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if isinstance(obj, Block):
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return self.on_receive_main_block(obj)
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def add_to_timequeue(self, obj):
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i = 0
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while i < len(self.timequeue) and self.timequeue[i].ts < obj.ts:
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i += 1
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self.timequeue.insert(i, obj)
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def add_to_multiset(self, _set, k, v):
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if k not in _set:
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_set[k] = []
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_set[k].append(v)
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def change_head(self, chain, new_head):
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chain.extend([None] * (new_head.number + 1 - len(chain)))
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i, c = new_head.number, new_head.hash
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while c != chain[i]:
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chain[i] = c
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c = self.blocks[c].parent_hash
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i -= 1
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for i in range(len(chain)):
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assert self.blocks[chain[i]].number == i
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assert self.blocks[chain[i]].ts <= self.ts
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def process_children(self, h):
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if h in self.parentqueue:
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for b in self.parentqueue[h]:
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self.on_receive(b, reprocess=True)
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del self.parentqueue[h]
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def have_ancestry(self, h):
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while h != genesis.hash:
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if h not in self.processed:
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return False
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h = self.processed[h].parent_hash
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return True
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def is_notarized(self, b):
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return b.hash in self.children
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def on_receive_main_block(self, block):
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# Parent not yet received
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if block.parent_hash not in self.blocks:
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self.add_to_multiset(self.parentqueue, block.parent_hash, block)
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return None
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if block.ts > self.ts:
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self.add_to_timequeue(block)
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return None
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self.log("Processing main chain block %s" % to_hex(block.hash[:4]))
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self.blocks[block.hash] = block
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# Reorg the main chain if new head
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if block.number > self.blocks[self.main_chain[-1]].number:
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reorging = (block.parent_hash != self.main_chain[-1])
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self.change_head(self.main_chain, block)
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# Add child record
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self.add_to_multiset(self.children, block.parent_hash, block.hash)
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# Final steps
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self.process_children(block.hash)
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self.network.broadcast(self, block)
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def is_descendant(self, a, b):
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a, b = self.blocks[a], self.blocks[b]
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while b.number > a.number:
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b = self.blocks[b.parent_hash]
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return a.hash == b.hash
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def tick(self):
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self.ts += 0.1
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self.log("Tick: %.1f" % self.ts, lvl=1)
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# Process time queue
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while len(self.timequeue) and self.timequeue[0].ts <= self.ts:
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self.on_receive(self.timequeue.pop(0), reprocess=True)
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# Attempt to mine a main chain block
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pownonce = random.randrange(65537)
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mchead = self.blocks[self.main_chain[-1]]
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if checkpow(mchead.pownonce, pownonce):
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assert self.ts >= mchead.ts
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self.broadcast(Block(mchead, pownonce, self.ts))
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