pwned-passwords-search.rb

#!/usr/bin/env ruby

require 'digest/sha1'

# search a file of "<sha1><crlf>"
def sha1_binsearch(io, target, linesize = 42, hashsize=40)
  low, high = 0, (io.size / linesize) - 1

  while low <= high
    mid = (low + high) / 2

    io.pos = mid * linesize
    midval = io.read(hashsize)

    if midval < target
      low = mid + 1
    elsif midval > target
      high = mid - 1
    else
      return true
    end
  end

  return false
end

db = File.new 'pwned-passwords-1.0.txt'

loop do
  print "Password: "
  pass = $stdin.gets.chomp
  exit if pass.empty?

  a = Time.new.to_f
  hash = Digest::SHA1.hexdigest(pass).upcase
  puts "Found: %s in %.2f ms" % [sha1_binsearch(db, hash), (Time.new.to_f - a) * 1000]
end