In Files

  • securerandom.rb

Class/Module Index [+]

Quicksearch

SecureRandom

Secure random number generator interface.

This library is an interface to secure random number generators which are suitable for generating session keys in HTTP cookies, etc.

You can use this library in your application by requiring it:

require 'securerandom'

It supports the following secure random number generators:

  • openssl

  • /dev/urandom

  • Win32

Examples

Generate random hexadecimal strings:

require 'securerandom'

p SecureRandom.hex(10) #=> "52750b30ffbc7de3b362"
p SecureRandom.hex(10) #=> "92b15d6c8dc4beb5f559"
p SecureRandom.hex(13) #=> "39b290146bea6ce975c37cfc23"

Generate random base64 strings:

p SecureRandom.base64(10) #=> "EcmTPZwWRAozdA=="
p SecureRandom.base64(10) #=> "KO1nIU+p9DKxGg=="
p SecureRandom.base64(12) #=> "7kJSM/MzBJI+75j8"

Generate random binary strings:

p SecureRandom.random_bytes(10) #=> "\016\t{\370g\310pbr\301"
p SecureRandom.random_bytes(10) #=> "\323U\030TO\234\357\020\a\337"

Generate UUIDs:

p SecureRandom.uuid #=> "2d931510-d99f-494a-8c67-87feb05e1594"
p SecureRandom.uuid #=> "bad85eb9-0713-4da7-8d36-07a8e4b00eab"

Public Class Methods

bytes(n) click to toggle source
 
               # File securerandom.rb, line 49
def bytes(n)
  return gen_random(n)
end
            
gen_random(n) click to toggle source
 
               # File securerandom.rb, line 53
def gen_random(n)
  ret = Random.urandom(n)
  if ret.nil?
    begin
      require 'openssl'
    rescue NoMethodError
      raise NotImplementedError, "No random device"
    else
      @rng_chooser.synchronize do
        class << self
          remove_method :gen_random
          alias gen_random gen_random_openssl
        end
      end
      return gen_random(n)
    end
  elsif ret.length != n
    raise NotImplementedError,                "Unexpected partial read from random device: "                "only #{ret.length} for #{n} bytes"
  else
    @rng_chooser.synchronize do
      class << self
        remove_method :gen_random
        alias gen_random gen_random_urandom
      end
    end
    return gen_random(n)
  end
end