#!/usr/bin/python
from random import random

# btc_el33t.py 0.2
# Dan Kaminsky, [email protected]

# simple numerical sim of @el33th4xor Bitcoin attack
# No conclusions should be drawn, except that it's
# _really_ sensitive to whether you can always win
# the race with the public pool.

# BUGFIX:  Previous version allowed both pub and priv
#          to win same round

pubpool = 0.66666
privpool = 0.33333
chance_of_losing_race = 0
prev  = 0
r =0
pubbtc = 0
privbtc = 0

# honest
if 0:
  while r<10000:
    print r, pubbtc, privbtc
    if random() < privpool:
        privbtc += 1
        r+=1
    if random() < pubpool:
        pubbtc  += 1
        r+=1

# dishonest
if 1:
  while r<10000:
    print r, pubbtc, privbtc, prev
    if random() < privpool:
        prev += 1
        r+=1
    if random() < pubpool:
        if prev==0:
            pubbtc  += 1
        if prev>0:
            if random() > chance_of_losing_race:
                privbtc += 1
            else:
                pubbtc  += 1
            prev-=1
        r+=1