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+#!/usr/bin/env python3
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+
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+import csv
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+import numpy
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+import os
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+import sys
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+
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+# Starting day: February Nth
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+#N = 1
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+N = 20
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+
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+# See note in readme
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+JAN_31 = 2459245
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+
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+# 2021 February Nth as Julian date
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+FIRST_DAY = JAN_31 + N
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+
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+TOTAL_BRIDGES = 1890
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+
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+OBFS4_EMAIL_BRIDGES = 93
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+
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+def sigfigs(n):
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+ if n == 0.0:
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+ n = 0 # as an int
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+ else:
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+ i=0
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+ while n * (10**i) < 1:
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+ i += 1
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+ n = round(n * 10**i) / 10**i
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+
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+ return n
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+
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+email_bridges = set()
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+
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+with open ("data/obfs4-email-bridges", 'r') as f:
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+ for line in f:
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+ if line != "":
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+ email_bridges.add(line.strip())
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+
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+rel_table = """
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+\\hline
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+$h$ & \\textbf{TP} & \\textbf{TN} & \\textbf{FP} & \\textbf{FN} & \\textbf{Precision} & \\textbf{Recall} \\\\
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+\\hline
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+"""
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+abs_table = rel_table
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+nomin_table = rel_table
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+
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+for harshness in range(5):
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+ for suffix in ["", "_abs", "_nomin"]:
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+ with open (f"data/blocked_{harshness}{suffix}", 'r') as f:
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+ # obfs4 email bridges correctly identified as blocked
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+ correct = 0
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+
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+ # obfs4 email bridges identified as blocked before they actually were
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+ too_soon = 0
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+
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+ # non-obfs4-email bridges incorrectly identified as blocked
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+ incorrect = 0
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+
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+ for line in f:
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+ if line != "":
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+ line = line.strip()
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+ fingerprint = line[:40]
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+ date = int(line[41:])
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+
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+ if fingerprint in email_bridges:
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+ if date >= FIRST_DAY:
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+ correct += 1
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+ else:
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+ too_soon += 1
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+ else:
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+ incorrect += 1
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+
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+ tn = TOTAL_BRIDGES - OBFS4_EMAIL_BRIDGES - incorrect
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+ tp = correct
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+ fn = OBFS4_EMAIL_BRIDGES - correct - too_soon
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+ fp = too_soon + incorrect
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+
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+ precision = sigfigs(tp / (tp + fp))
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+
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+ recall = sigfigs(tp / (tp + fn))
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+
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+ newline = f"{harshness} & {tp} & {tn} & {fp} & {fn} & {precision} & {recall} \\\\\n"
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+
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+ if suffix == "":
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+ rel_table += newline
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+ elif suffix == "_abs":
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+ abs_table += newline
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+ else:
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+ nomin_table += newline
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+
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+print ("Absolute threshold without a minimum:")
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+print (nomin_table)
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+
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+print ("Absolute threshold:")
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+print (abs_table)
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+
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+print ("Relative threshold:")
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+print (rel_table)
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+
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+
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+# Now let's look at stddevs
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+
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+email_bridges = list(email_bridges)
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+email_bridge_data = []
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+email_bridge_max = []
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+
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+for fingerprint in email_bridges:
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+ # We're going to get all the data for each bridge
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+ bridge_data = dict()
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+ begun = False
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+ max_count = 0
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+
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+ filename = f"data/bridge_data_cleaned/{fingerprint.upper()}"
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+
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+ if os.path.isfile(filename) and os.path.getsize(filename) > 0:
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+ with open(filename, 'r') as csvfile:
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+ data = csv.reader(csvfile, delimiter=',')
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+
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+ for line in data:
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+
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+ # Ignore 0 values until we see a non-zero value
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+ if not begun:
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+ if line[1] != "0":
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+ begun = True
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+
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+ if begun:
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+ date = int(line[0][:line[0].find(' ')])
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+ val = int(line[1])
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+ bridge_data[date] = val
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+ max_count = max(max_count, val)
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+
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+ if begun:
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+ email_bridge_data.append(bridge_data)
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+ email_bridge_max.append(max_count)
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+
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+# Look at bridges individually
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+for i in range(len(email_bridge_data)):
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+ bridge = email_bridge_data[i]
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+
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+ vals = []
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+
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+ # Get smallest key, i.e., first date we have data for
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+ start_date = min(bridge)
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+
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+ # Get counts before censorship started
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+ #for d in range(start_date, FIRST_DAY):
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+ # if d in bridge:
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+ # vals.append(bridge[d])
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+ # If this day is not represented, the bridge did not report
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+ # stats; this is different from 0.
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+
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+ # Note: This is cheaper than the above impelmentation.
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+ for date, val in bridge.items():
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+ if date < FIRST_DAY:
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+ vals.append(val)
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+
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+ # If we have no data, don't worry about it
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+ if len(vals) == 0:
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+ continue
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+
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+ mu = numpy.mean(vals)
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+ sigma = numpy.std(vals)
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+
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+ if sigma > 0:
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+ print (f"Single: Bridge {i}: max={email_bridge_max[i]}, mean={mu}, std={sigma}")
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+ print (f"Single: Zero is {mu / sigma} standard deviations away from the mean ({mu})")
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+ print (f"Single: We are looking at data from {len(vals)} days, starting on {start_date}\n")
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+
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+# Look at pairs of bridges
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+for i in range(len(email_bridge_data)):
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+ for j in range(i+1, len(email_bridge_data)):
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+ max_count = 0
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+
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+ bridge_i = email_bridge_data[i]
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+ bridge_j = email_bridge_data[j]
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+
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+ vals = []
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+
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+ # Get smallest key, i.e., the first date BOTH bridges have data for
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+ start_date = max(min(bridge_i), min(bridge_j))
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+
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+ # Get counts before censorship started
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+ #for d in range(start_date, FIRST_DAY):
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+
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+ # Get set of keys between start_date and FIRST_DAY
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+ keys = set()
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+ for d in bridge_i:
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+ if d >= start_date and d <= FIRST_DAY:
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+ keys.add(d)
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+ for d in bridge_j:
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+ if d >= start_date and d <= FIRST_DAY:
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+ keys.add(d)
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+
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+ for d in keys:
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+ val = 0
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+ if d in bridge_i and d in bridge_j:
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+ val = bridge_i[d] + bridge_j[d]
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+ elif d in bridge_i:
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+ val = bridge_i[d]
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+ elif d in bridge_j:
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+ val = bridge_j[d]
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+
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+ vals.append(val)
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+ max_count = max(max_count, val)
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+
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+ # If we have no data, don't worry about it
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+ if len(vals) == 0:
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+ continue
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+
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+ mu = numpy.mean(vals)
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+ sigma = numpy.std(vals)
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+
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+ if sigma > 0:
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+ print (f"Double: Bridges {i} and {j}: max={max_count}, mean={mu}, std={sigma}")
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+ print (f"Double: Zero is {mu / sigma} standard deviations away from the mean ({mu})")
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+ print (f"Double: We are looking at data from {len(vals)} days, starting on {start_date}\n")
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