Module: OpenID::CryptUtil

Defined in:
lib/openid/cryptutil.rb

Overview

This module contains everything needed to perform low-level cryptograph and data manipulation tasks.

Class Method Summary collapse

Class Method Details

.base64_to_num(s) ⇒ Object

Decode a base64 byte string to a number.



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# File 'lib/openid/cryptutil.rb', line 98

def self.base64_to_num(s)
  binary_to_num(OpenID::Util.from_base64(s))
end

.binary_to_num(s) ⇒ Object

Convert a string of bytes into a number.



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# File 'lib/openid/cryptutil.rb', line 81

def self.binary_to_num(s)
  # taken from openid-ruby 0.0.1
  s = "\000" * (4 - (s.length % 4)) + s
  num = 0
  s.unpack("N*").each do |x|
    num <<= 32
    num |= x
  end
  num
end

.const_eq(s1, s2) ⇒ Object 



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# File 'lib/openid/cryptutil.rb', line 102

def self.const_eq(s1, s2)
  return false if s1.length != s2.length

  result = true
  s1.length.times do |i|
    result &= (s1[i] == s2[i])
  end
  result
end

.hmac_sha1(key, text) ⇒ Object 



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# File 'lib/openid/cryptutil.rb', line 41

def self.hmac_sha1(key, text)
  return HMAC::SHA1.digest(key, text) unless defined? OpenSSL

  OpenSSL::HMAC.digest(OpenSSL::Digest.new("SHA1"), key, text)
end

.hmac_sha256(key, text) ⇒ Object 



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# File 'lib/openid/cryptutil.rb', line 51

def self.hmac_sha256(key, text)
  return HMAC::SHA256.digest(key, text) unless defined? OpenSSL

  OpenSSL::HMAC.digest(OpenSSL::Digest.new("SHA256"), key, text)
end

.num_to_base64(l) ⇒ Object

Encode a number as a base64-encoded byte string.



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# File 'lib/openid/cryptutil.rb', line 93

def self.num_to_base64(l)
  OpenID::Util.to_base64(num_to_binary(l))
end

.num_to_binary(n) ⇒ Object

Convert a number to its binary representation; return a string of bytes.



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# File 'lib/openid/cryptutil.rb', line 73

def self.num_to_binary(n)
  bits = n.to_s(2)
  prepend = (8 - bits.length % 8)
  bits = ("0" * prepend) + bits
  [bits].pack("B*")
end

.rand(max) ⇒ Object

Generate a random number, doing a little extra work to make it more likely that it’s suitable for cryptography. If your system doesn’t have /dev/urandom then this number is not cryptographically safe. See <www.cosine.org/2007/08/07/security-ruby-kernel-rand/> for more information. max is the largest possible value of such a random number, where the result will be less than max.



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# File 'lib/openid/cryptutil.rb', line 32

def self.rand(max)
  Kernel.srand
  Kernel.rand(max)
end

.random_string(length, chars = nil) ⇒ Object

Generate a random string of the given length, composed of the specified characters. If chars is nil, generate a string composed of characters in the range 0..255.



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# File 'lib/openid/cryptutil.rb', line 60

def self.random_string(length, chars = nil)
  s = ""

  if chars.nil?
    length.times { s << rand(256).chr }
  else
    length.times { s << chars[rand(chars.length)] }
  end
  s
end

.sha1(text) ⇒ Object 



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# File 'lib/openid/cryptutil.rb', line 37

def self.sha1(text)
  Digest::SHA1.digest(text)
end

.sha256(text) ⇒ Object 



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# File 'lib/openid/cryptutil.rb', line 47

def self.sha256(text)
  Digest::SHA256.digest(text)
end