Simple demonstration of hashcash in ruby

hashcash.rb

#!/usr/bin/env ruby

require 'digest'
require 'securerandom'

difficulty = 6
message = "hello"

hash = "1"*difficulty
random_value = nil

until hash[0..difficulty-1] == "0"*difficulty
        random_value = SecureRandom.hex.to_s
	hash = (Digest::SHA1.hexdigest(message+random_value)).to_s
end

puts "#{hash} generated with random value #{random_value}"