# -*- coding: us-ascii -*-
# frozen_string_literal: true
# == 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
#
# SecureRandom is extended by the Random::Formatter module which
# defines the following methods:
#
# * alphanumeric
# * base64
# * choose
# * gen_random
# * hex
# * rand
# * random_bytes
# * random_number
# * urlsafe_base64
# * uuid
#
# These methods are usable as class methods of SecureRandom such as
# `SecureRandom.hex`.
#
# === Examples
#
# Generate random hexadecimal strings:
#
# require 'securerandom'
#
# SecureRandom.hex(10) #=> "52750b30ffbc7de3b362"
# SecureRandom.hex(10) #=> "92b15d6c8dc4beb5f559"
# SecureRandom.hex(13) #=> "39b290146bea6ce975c37cfc23"
#
# Generate random base64 strings:
#
# SecureRandom.base64(10) #=> "EcmTPZwWRAozdA=="
# SecureRandom.base64(10) #=> "KO1nIU+p9DKxGg=="
# SecureRandom.base64(12) #=> "7kJSM/MzBJI+75j8"
#
# Generate random binary strings:
#
# SecureRandom.random_bytes(10) #=> "\016\t{\370g\310pbr\301"
# SecureRandom.random_bytes(10) #=> "\323U\030TO\234\357\020\a\337"
#
# Generate alphanumeric strings:
#
# SecureRandom.alphanumeric(10) #=> "S8baxMJnPl"
# SecureRandom.alphanumeric(10) #=> "aOxAg8BAJe"
#
# Generate UUIDs:
#
# SecureRandom.uuid #=> "2d931510-d99f-494a-8c67-87feb05e1594"
# SecureRandom.uuid #=> "bad85eb9-0713-4da7-8d36-07a8e4b00eab"
#
module SecureRandom
class << self
def bytes(n)
return gen_random(n)
end
private
def gen_random_openssl(n)
@pid = 0 unless defined?(@pid)
pid = $$
unless @pid == pid
now = Process.clock_gettime(Process::CLOCK_REALTIME, :nanosecond)
OpenSSL::Random.random_add([now, @pid, pid].join(""), 0.0)
seed = Random.urandom(16)
if (seed)
OpenSSL::Random.random_add(seed, 16)
end
@pid = pid
end
return OpenSSL::Random.random_bytes(n)
end
def gen_random_urandom(n)
ret = Random.urandom(n)
unless ret
raise NotImplementedError, "No random device"
end
unless ret.length == n
raise NotImplementedError, "Unexpected partial read from random device: only #{ret.length} for #{n} bytes"
end
ret
end
ret = Random.urandom(1)
if ret.nil?
begin
require 'openssl'
rescue NoMethodError
raise NotImplementedError, "No random device"
else
alias gen_random gen_random_openssl
end
else
alias gen_random gen_random_urandom
end
public :gen_random
end
end
module Random::Formatter
# SecureRandom.random_bytes generates a random binary string.
#
# The argument _n_ specifies the length of the result string.
#
# If _n_ is not specified or is nil, 16 is assumed.
# It may be larger in future.
#
# The result may contain any byte: "\x00" - "\xff".
#
# require 'securerandom'
#
# SecureRandom.random_bytes #=> "\xD8\\\xE0\xF4\r\xB2\xFC*WM\xFF\x83\x18\xF45\xB6"
# SecureRandom.random_bytes #=> "m\xDC\xFC/\a\x00Uf\xB2\xB2P\xBD\xFF6S\x97"
#
# If a secure random number generator is not available,
# +NotImplementedError+ is raised.
def random_bytes(n=nil)
n = n ? n.to_int : 16
gen_random(n)
end
# SecureRandom.hex generates a random hexadecimal string.
#
# The argument _n_ specifies the length, in bytes, of the random number to be generated.
# The length of the resulting hexadecimal string is twice of _n_.
#
# If _n_ is not specified or is nil, 16 is assumed.
# It may be larger in the future.
#
# The result may contain 0-9 and a-f.
#
# require 'securerandom'
#
# SecureRandom.hex #=> "eb693ec8252cd630102fd0d0fb7c3485"
# SecureRandom.hex #=> "91dc3bfb4de5b11d029d376634589b61"
#
# If a secure random number generator is not available,
# +NotImplementedError+ is raised.
def hex(n=nil)
random_bytes(n).unpack("H*")[0]
end
# SecureRandom.base64 generates a random base64 string.
#
# The argument _n_ specifies the length, in bytes, of the random number
# to be generated. The length of the result string is about 4/3 of _n_.
#
# If _n_ is not specified or is nil, 16 is assumed.
# It may be larger in the future.
#
# The result may contain A-Z, a-z, 0-9, "+", "/" and "=".
#
# require 'securerandom'
#
# SecureRandom.base64 #=> "/2BuBuLf3+WfSKyQbRcc/A=="
# SecureRandom.base64 #=> "6BbW0pxO0YENxn38HMUbcQ=="
#
# If a secure random number generator is not available,
# +NotImplementedError+ is raised.
#
# See RFC 3548 for the definition of base64.
def base64(n=nil)
[random_bytes(n)].pack("m0")
end
# SecureRandom.urlsafe_base64 generates a random URL-safe base64 string.
#
# The argument _n_ specifies the length, in bytes, of the random number
# to be generated. The length of the result string is about 4/3 of _n_.
#
# If _n_ is not specified or is nil, 16 is assumed.
# It may be larger in the future.
#
# The boolean argument _padding_ specifies the padding.
# If it is false or nil, padding is not generated.
# Otherwise padding is generated.
# By default, padding is not generated because "=" may be used as a URL delimiter.
#
# The result may contain A-Z, a-z, 0-9, "-" and "_".
# "=" is also used if _padding_ is true.
#
# require 'securerandom'
#
# SecureRandom.urlsafe_base64 #=> "b4GOKm4pOYU