1 files changed, 74 insertions, 0 deletions
diff --git a/tests/block_weight/block_weight.py b/tests/block_weight/block_weight.py
new file mode 100755
index 000000000..06aaabb02
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+++ b/tests/block_weight/block_weight.py
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+#!/usr/bin/python
+# Simulate a maximal block attack on the Monero network
+# This uses the scheme proposed by ArticMine
+# Written by Sarang Nother
+# Copyright (c) 2019 The Monero Project
+import sys
+import math
+
+MEDIAN_WINDOW_SMALL = 100 # number of recent blocks for median computation
+MEDIAN_WINDOW_BIG = 5000
+MULTIPLIER_SMALL = 1.4 # multipliers for determining weights
+MULTIPLIER_BIG = 50.0
+MEDIAN_THRESHOLD = 300*1000 # initial value for median (scaled kB -> B)
+lcg_seed = 0
+embw = MEDIAN_THRESHOLD
+ltembw = MEDIAN_THRESHOLD
+
+weights = [MEDIAN_THRESHOLD]*MEDIAN_WINDOW_SMALL # weights of recent blocks (B), with index -1 most recent
+lt_weights = [MEDIAN_THRESHOLD]*MEDIAN_WINDOW_BIG # long-term weights
+
+# Compute the median of a list
+def get_median(vec):
+    #temp = vec
+    temp = sorted(vec)
+    if len(temp) % 2 == 1:
+        return temp[len(temp)/2]
+    else:
+        return int((temp[len(temp)/2]+temp[len(temp)/2-1])/2)
+
+def LCG():
+  global lcg_seed
+  lcg_seed = (lcg_seed * 0x100000001b3 + 0xcbf29ce484222325) & 0xffffffff
+  return lcg_seed
+
+def run(t, blocks):
+  global embw
+  global ltembw
+
+  weights = [MEDIAN_THRESHOLD]*MEDIAN_WINDOW_SMALL # weights of recent blocks (B), with index -1 most recent
+  lt_weights = [MEDIAN_THRESHOLD]*MEDIAN_WINDOW_BIG # long-term weights
+
+  for block in range(blocks):
+      # determine the long-term effective weight
+      ltmedian = get_median(lt_weights[-MEDIAN_WINDOW_BIG:])
+      ltembw = max(MEDIAN_THRESHOLD,ltmedian)
+
+      # determine the effective weight
+      stmedian = get_median(weights[-MEDIAN_WINDOW_SMALL:])
+      embw = min(max(MEDIAN_THRESHOLD,stmedian),int(MULTIPLIER_BIG*ltembw))
+
+      # drop the lowest values
+      weights = weights[1:]
+      lt_weights = lt_weights[1:]
+
+      # add a block of max weight
+      if t == 0:
+        max_weight = 2 * embw
+      elif t == 1:
+        r = LCG()
+        max_weight = int(90 + r % 500000 + 250000 + math.sin(block / 200.) * 350000)
+        if max_weight < 90: max_weight = 90
+      elif t == 2:
+        max_weight = 90
+      else:
+        sys.exit(1)
+      weights.append(max_weight)
+      lt_weights.append(min(max_weight,int(ltembw + int(ltembw * 2 / 5))))
+
+      #print "H %u, r %u, BW %u, EMBW %u, LTBW %u, LTEMBW %u, ltmedian %u" % (block, r, max_weight, embw, lt_weights[-1], ltembw, ltmedian)
+      print "H %u, BW %u, EMBW %u, LTBW %u" % (block, max_weight, embw, lt_weights[-1])
+
+run(0, 2 * MEDIAN_WINDOW_BIG)
+run(1, 9 * MEDIAN_WINDOW_BIG)
+run(2, 1 * MEDIAN_WINDOW_BIG)