Simple binary search of Troy Hunt's password list

search.py

#!/usr/bin/python

import sys
import sha

f = open('/tmp/pwned-passwords-1.0.txt')
minpos = 0
f.seek(0, 2)
maxpos = f.tell() / 42  # Number of hashes

pw = sys.argv[1]
pwhash = sha.new(pw).hexdigest().upper()


def read_hash(position):
    f.seek(position * 42)
    return f.readline().strip()


while True:
    if (maxpos - minpos) <= 1:
        if pwhash in (read_hash(minpos), read_hash(maxpos)):
            print 'Match'
        else:
            print 'No match'
        break
    position = (minpos + maxpos) / 2
    chash = read_hash(position)
    if chash == pwhash:
        print 'Match!'
        break
    elif pwhash < chash:
        maxpos = position
    elif pwhash > chash:
        minpos = position