diff --git a/clock_disparity/distributions.py b/clock_disparity/distributions.py new file mode 100644 index 0000000..6412e3d --- /dev/null +++ b/clock_disparity/distributions.py @@ -0,0 +1,37 @@ +import random, sys + + +def normal_distribution(mean, standev): + def f(): + return int(random.normalvariate(mean, standev)) + + return f + + +def exponential_distribution(mean): + def f(): + total = 0 + while 1: + total += 1 + if not random.randrange(32): + break + return int(total * 0.03125 * mean) + + return f + + +def convolve(*args): + def f(): + total = 0 + for arg in args: + total += arg() + return total + + return f + + +def transform(dist, xformer): + def f(): + return xformer(dist()) + + return f diff --git a/clock_disparity/networksim.py b/clock_disparity/networksim.py new file mode 100644 index 0000000..2415262 --- /dev/null +++ b/clock_disparity/networksim.py @@ -0,0 +1,75 @@ +from distributions import transform, normal_distribution +import random + + +class NetworkSimulator(): + + def __init__(self, latency=50): + self.agents = [] + self.latency_distribution_sample = transform(normal_distribution(latency, (latency * 2) // 5), lambda x: max(x, 0)) + self.time = 0 + self.objqueue = {} + self.peers = {} + self.reliability = 0.9 + + def generate_peers(self, num_peers=5): + self.peers = {} + for a in self.agents: + p = [] + while len(p) <= num_peers // 2: + p.append(random.choice(self.agents)) + if p[-1] == a: + p.pop() + self.peers[a.id] = self.peers.get(a.id, []) + p + for peer in p: + self.peers[peer.id] = self.peers.get(peer.id, []) + [a] + + def tick(self): + if self.time in self.objqueue: + for recipient, obj in self.objqueue[self.time]: + if random.random() < self.reliability: + recipient.on_receive(obj) + del self.objqueue[self.time] + for a in self.agents: + a.tick() + self.time += 1 + + def run(self, steps): + for i in range(steps): + self.tick() + + def broadcast(self, sender, obj): + for p in self.peers[sender.id]: + recv_time = self.time + self.latency_distribution_sample() + if recv_time not in self.objqueue: + self.objqueue[recv_time] = [] + self.objqueue[recv_time].append((p, obj)) + + def direct_send(self, to_id, obj): + for a in self.agents: + if a.id == to_id: + recv_time = self.time + self.latency_distribution_sample() + if recv_time not in self.objqueue: + self.objqueue[recv_time] = [] + self.objqueue[recv_time].append((a, obj)) + + def knock_offline_random(self, n): + ko = {} + while len(ko) < n: + c = random.choice(self.agents) + ko[c.id] = c + for c in ko.values(): + self.peers[c.id] = [] + for a in self.agents: + self.peers[a.id] = [x for x in self.peers[a.id] if x.id not in ko] + + def partition(self): + a = {} + while len(a) < len(self.agents) / 2: + c = random.choice(self.agents) + a[c.id] = c + for c in self.agents: + if c.id in a: + self.peers[c.id] = [x for x in self.peers[c.id] if x.id in a] + else: + self.peers[c.id] = [x for x in self.peers[c.id] if x.id not in a] diff --git a/clock_disparity/node.py b/clock_disparity/node.py new file mode 100644 index 0000000..5ca4a7b --- /dev/null +++ b/clock_disparity/node.py @@ -0,0 +1,151 @@ +import os +from binascii import hexlify +from Crypto.Hash import keccak +import random + +def to_hex(s): + return hexlify(s).decode('utf-8') + +memo = {} + +def sha3(x): + if x not in memo: + memo[x] = keccak.new(digest_bits=256, data=x).digest() + return memo[x] + +def hash_to_int(h): + o = 0 + for c in h: + o = (o << 8) + c + return o + +NOTARIES = 40 +BASE_TS_DIFF = 1 +SKIP_TS_DIFF = 6 +SAMPLE = 9 +MIN_SAMPLE = 5 +POWDIFF = 50 * NOTARIES +SHARDS = 12 + +def checkpow(work, nonce): + # Discrete log PoW, lolz + # Quadratic nonresidues only + return pow(work, nonce, 65537) * POWDIFF < 65537 * 2 and pow(nonce, 32768, 65537) == 65536 + +class MainChainBlock(): + def __init__(self, parent, pownonce, ts): + self.parent_hash = parent.hash if parent else (b'\x00' * 32) + assert isinstance(self.parent_hash, bytes) + self.hash = sha3(self.parent_hash + str(pownonce).encode('utf-8')) + self.ts = ts + if parent: + assert checkpow(parent.pownonce, pownonce) + assert self.ts >= parent.ts + self.pownonce = pownonce + self.number = 0 if parent is None else parent.number + 1 + + +main_genesis = MainChainBlock(None, 59049, 0) + +class Node(): + + def __init__(self, _id, network, sleepy=False, careless=False, ts=0): + self.blocks = { + main_genesis.hash: main_genesis + } + self.main_chain = [main_genesis.hash] + self.timequeue = [] + self.parentqueue = {} + self.children = {} + self.ts = ts + self.id = _id + self.network = network + self.used_parents = {} + self.processed = {} + self.sleepy = sleepy + self.careless = careless + + def broadcast(self, x): + if self.sleepy and self.ts: + return + self.network.broadcast(self, x) + self.on_receive(x) + + def log(self, words, lvl=3, all=False): + #if "Tick:" != words[:5] or self.id == 0: + if (self.id == 0 or all) and lvl >= 2: + print(self.id, words) + + def on_receive(self, obj, reprocess=False): + if obj.hash in self.processed and not reprocess: + return + self.processed[obj.hash] = True + if isinstance(obj, MainChainBlock): + return self.on_receive_main_block(obj) + + def add_to_timequeue(self, obj): + i = 0 + while i < len(self.timequeue) and self.timequeue[i].ts < obj.ts: + i += 1 + self.timequeue.insert(i, obj) + + def add_to_multiset(self, _set, k, v): + if k not in _set: + _set[k] = [] + _set[k].append(v) + + def change_head(self, chain, new_head): + chain.extend([None] * (new_head.number + 1 - len(chain))) + i, c = new_head.number, new_head.hash + while c != chain[i]: + chain[i] = c + c = self.blocks[c].parent_hash + i -= 1 + for i in range(len(chain)): + assert self.blocks[chain[i]].number == i + assert self.blocks[chain[i]].ts <= self.ts + + def process_children(self, h): + if h in self.parentqueue: + for b in self.parentqueue[h]: + self.on_receive(b, reprocess=True) + del self.parentqueue[h] + + def on_receive_main_block(self, block): + # Parent not yet received + if block.parent_hash not in self.blocks: + self.add_to_multiset(self.parentqueue, block.parent_hash, block) + return None + if block.ts > self.ts: + self.add_to_timequeue(block) + return None + self.log("Processing main chain block %s" % to_hex(block.hash[:4])) + self.blocks[block.hash] = block + # Reorg the main chain if new head + if block.number > self.blocks[self.main_chain[-1]].number: + reorging = (block.parent_hash != self.main_chain[-1]) + self.change_head(self.main_chain, block) + # Add child record + self.add_to_multiset(self.children, block.parent_hash, block.hash) + # Final steps + self.process_children(block.hash) + self.network.broadcast(self, block) + + def is_descendant(self, a, b): + a, b = self.blocks[a], self.blocks[b] + while b.number > a.number: + b = self.blocks[b.parent_hash] + return a.hash == b.hash + + def tick(self): + self.ts += 0.1 + self.log("Tick: %.1f" % self.ts, lvl=1) + # Process time queue + while len(self.timequeue) and self.timequeue[0].ts <= self.ts: + self.on_receive(self.timequeue.pop(0)) + # Attempt to mine a main chain block + pownonce = random.randrange(65537) + mchead = self.blocks[self.main_chain[-1]] + if checkpow(mchead.pownonce, pownonce): + assert self.ts >= mchead.ts + self.broadcast(MainChainBlock(mchead, pownonce, self.ts)) diff --git a/clock_disparity/test.py b/clock_disparity/test.py new file mode 100644 index 0000000..a942e9a --- /dev/null +++ b/clock_disparity/test.py @@ -0,0 +1,46 @@ +from networksim import NetworkSimulator +from node import Node, NOTARIES, MainChainBlock, main_genesis +from distributions import normal_distribution + +net = NetworkSimulator(latency=12) +notaries = [Node(i, net, ts=max(normal_distribution(50, 50)(), 0)) for i in range(NOTARIES)] +net.agents = notaries +net.generate_peers() +for i in range(4000): + net.tick() +for n in notaries: + print("Main chain head: %d" % n.blocks[n.main_chain[-1]].number) + print("Total main chain blocks received: %d" % (len([b for b in n.blocks.values() if isinstance(b, MainChainBlock)]) - 1)) + +import matplotlib.pyplot as plt +import networkx as nx +import random + +G=nx.Graph() + +#positions = {main_genesis.hash: 0, beacon_genesis.hash: 0} +#queue = [ + +for b in n.blocks.values(): + if b.number > 0: + if isinstance(b, MainChainBlock): + G.add_edge(b.hash, b.parent_hash, color='b') + +cache = {main_genesis.hash: 0} + +def mkoffset(b): + if b.hash not in cache: + cache[b.hash] = cache[b.parent_hash] + random.randrange(35) + return cache[b.hash] + +pos={b.hash: (b.ts + mkoffset(b), b.ts) for b in n.blocks.values()} +edges = G.edges() +colors = [G[u][v]['color'] for u,v in edges] +nx.draw_networkx_nodes(G,pos,node_size=10,node_shape='o',node_color='0.75') + +nx.draw_networkx_edges(G,pos, + width=2,edge_color=colors) + +plt.axis('off') +# plt.savefig("degree.png", bbox_inches="tight") +plt.show() diff --git a/randao_analysis/paths.py b/randao_analysis/paths.py index dd8aa8f..b7bb4a3 100644 --- a/randao_analysis/paths.py +++ b/randao_analysis/paths.py @@ -7,7 +7,7 @@ SKIP = 6 # The score of a node in the search graph, for A* search def score_node(n): time, height = n - return time - height * (LATENCY + 0.0000001) + return time - height * (LATENCY * 5.0 + 0.0000001) # `alpha`: percentage of the network controlled by the actor # `max_height`: stop at this height @@ -120,7 +120,7 @@ def test(): # Assume attacker has (0.40, 0.38, 0.36, 0.34, 0.32, 0.30, 0.28); check race probs for handicap 1-8 print("Basic tests\n") for alpha in (0.40, 0.38, 0.36, 0.34, 0.32, 0.30, 0.28): - race_results = [race(alpha, 1-alpha, 100) for j in range(100)] + race_results = [race(alpha, 1-alpha, 1000) for j in range(100)] probs = [] for i in range(1, 9): probs.append(len([x for x in race_results if x >= i]) / 100) @@ -130,7 +130,7 @@ def test(): # if either side has share p, they effectively "really" have share p**3 print("\nRequiring 2/2 notarization\n") for alpha in (0.45, 0.44, 0.43, 0.42, 0.41, 0.40, 0.39): - race_results = [race(alpha ** 3, (1-alpha) ** 3, 100) for j in range(100)] + race_results = [race(alpha ** 3, (1-alpha) ** 3, 1000) for j in range(100)] probs = [] for i in range(1, 9): probs.append(len([x for x in race_results if x >= i]) / 100)