DH鍵共有

dh_client.rb

#!/usr/bin/env ruby

require 'prime'
require 'securerandom'
require 'socket'
require 'json'
require 'io/console/size'

raise ArgumentError if ARGV.count < 2

host = ARGV.shift
port = ARGV.shift.to_i


def prime_number
  p = 0

  SecureRandom.random_number(2**32).step(0, -1) do |n|
    if n.prime?
      p = n
      break
    end
  end

  return p
end

def dump_remote_data(data)
  tag = "TO CLIENT"
  columns = IO.console_size[1]
  data_length = data.to_s.inspect.length

  left_padding = " " * (columns / 2 - data_length / 2 )
  right_padding = " <-" + tag + "-" * (columns / 2 - data_length / 2 - tag.length - 4)

  puts "#{left_padding}#{data.inspect}#{right_padding}"
end

def dump_local_data(data)
  tag = "TO SERVER"
  columns = IO.console_size[1]
  data_length = data.to_s.inspect.length

  left_padding  = "-" * (columns / 2 - data_length / 2 - tag.length - 3) + tag  + "-> "
  right_padding = " " * (columns / 2 - data_length / 2 - 1) 

  puts "#{left_padding}#{data.inspect}#{right_padding}"
end

def debug_print(data)
  data_length = data.to_s.length
  columns = IO.console_size[1]
  left_padding =  " " * (columns / 2 - data_length / 2 - 2 ) + "> "
  right_padding =  " <" + " " * (columns / 2 - data_length / 2 - 3)

  puts "#{left_padding}#{data.to_s}#{right_padding}"
end
socket = TCPSocket.new(host, port)

p = 0
privkey = 0

#p = prime_number
#data = {p: p}.to_json + "\r\n"
#socket.write(data)
#dump_local_data(data)

loop do
  data = socket.gets
  dump_remote_data(data)
  json = JSON.parse(data, symbolize_names: true)

  case true
  when json.has_key?(:p) 
    p = json[:p]
    privkey = SecureRandom.random_number(p - 2)
    debug_print "privkey=#{privkey}"
    g = 2.pow(privkey, p)
    debug_print "g=#{g}"
    data = {g: g}.to_json + "\r\n"
    socket.write(data)
    dump_local_data(data)
  when json.has_key?(:g)
    r = json[:g]
    privkey = SecureRandom.random_number(p - 2)  if privkey == 0
    debug_print "privkey=#{privkey}"
    k = r.pow(privkey, p)
    debug_print "k=#{k}"
    socket.close
    exit
  else
    print "key not found"
  end
end

dh_server.rb

#!/usr/bin/env ruby

require 'prime'
require 'securerandom'
require 'socket'
require 'json'
require 'io/console/size'


tcpserver = TCPServer.open(5001) 


def prime_number
  return 41980824156648151

  p = 0

  SecureRandom.random_number(2**56).step(0, -1) do |n|
    if n.prime?
      p = n
      break
    end
  end

  return p
end


def dump_remote_data(data)
  tag = "TO SERVER"
  columns = IO.console_size[1]
  data_length = data.to_s.inspect.length

  left_padding = " " * (columns / 2 - data_length / 2 )
  right_padding = " <-" + tag + "-" * (columns / 2 - data_length / 2 - tag.length - 4)

  puts "#{left_padding}#{data.inspect}#{right_padding}"
end

def dump_local_data(data, peer)
  tag = "TO CLIENT #{peer}"
  columns = IO.console_size[1]
  data_length = data.to_s.inspect.length

  left_padding  = "-" * (columns / 2 - data_length / 2 - tag.length - 3) + tag  + "-> "
  right_padding = " " * (columns / 2 - data_length / 2 - 1) 

  puts "#{left_padding}#{data.inspect}#{right_padding}"
end

def debug_print(data)
  data_length = data.to_s.length
  columns = IO.console_size[1]
  left_padding =  " " * (columns / 2 - data_length / 2 - 2 ) + "> "
  right_padding =  " <" + " " * (columns / 2 - data_length / 2 - 3)

  puts "#{left_padding}#{data.to_s}#{right_padding}"
end


loop do 
  Thread.new(tcpserver.accept) do |s|
    sock_domain, remote_port, remote_hostname, remote_ip = s.peeraddr
    client_info = "|#{remote_ip}:#{remote_port}|"
    puts "Connection received: #{client_info}"

    p = 0
    privkey = 0

    p = prime_number
    privkey = SecureRandom.random_number(p - 2)
    data  = { p: p}.to_json + "\r\n"
    s.write(data)
    dump_local_data(data, client_info)

    while s.gets
      data = $_
      dump_remote_data(data)

      json = JSON.parse(data, symbolize_names: true)
      case true
      when json.has_key?(:g)
        r = json[:g]

        g = 2.pow(privkey, p)
        debug_print "g=#{g}"
        data = {g: g}.to_json + "\r\n"
        s.write(data)
        dump_local_data(data, client_info)
        k = r.pow(privkey, p)
        debug_print "k=#{k}"
      when json.has_key?(:p)
=begin
        p = json[:p]
        privkey = SecureRandom.random_number(p - 2) if privkey == 0
        debug_print "privkey=#{privkey}"

        g = 2.pow(privkey, p)
        debug_print "g=#{g}"
        data = {g: g}.to_json + "\r\n"
        s.write(data)
        dump_local_data(data, client_info)
=end
      else
        puts "key not found"
      end

    end
    s.close
  end

end