key.rb

require 'digest/sha2'
class Key < Binary 'H*'
  unit :to_s

  class << self
    def hexdigest(src, bitlen = 256)
      Digest::SHA2.new(bitlen).update(src.to_s).to_s
    end
      
    def gen(src)
      new(hexdigest(src))
    end
  end
    
  def initialize(key = nil)
    if key.nil?
      @key_s = Key.hexdigest(rand(Time.now.to_i)) # Fixme
    else
      if key.is_a?(Integer)
        @key_i = key
      elsif key.is_a?(String)
        @key_s = key
      else
        raise "Invalid key #{key}"
      end
    end
  end
    
  def to_i
    @key_i ||= @key_s.to_i(16)
  end
    
  def to_s
    @key_s ||= @key_i.to_s(16)
  end

  def ^(key)
    self.to_i ^ key.to_i
  end
    
  def ==(key)
    key.is_a?(Key) && (to_i == key.to_i) || key.is_a?(Integer) && (to_i == key)
  end
end