# -*- coding: us-ascii -*-
# frozen_string_literal: true
require 'random/formatter'
# == 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+.
#
# If a secure random number generator is not available,
# +NotImplementedError+ is raised.
module SecureRandom
# The version
VERSION = "0.4.1"
class << self
# Returns a random binary string containing +size+ bytes.
#
# See Random.bytes
def bytes(n)
return gen_random(n)
end
# Compatibility methods for Ruby 3.2, we can remove this after dropping to support Ruby 3.2
def alphanumeric(n = nil, chars: ALPHANUMERIC)
n = 16 if n.nil?
choose(chars, n)
end if RUBY_VERSION < '3.3'
private
# :stopdoc:
# Implementation using OpenSSL
def gen_random_openssl(n)
return OpenSSL::Random.random_bytes(n)
end
# Implementation using system random device
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
begin
# Check if Random.urandom is available
Random.urandom(1)
alias gen_random gen_random_urandom
rescue RuntimeError
begin
require 'openssl'
rescue NoMethodError
raise NotImplementedError, "No random device"
else
alias gen_random gen_random_openssl
end
end
# :startdoc:
# Generate random data bytes for Random::Formatter
public :gen_random
end
end
SecureRandom.extend(Random::Formatter)
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