module ActiveSupport::SecurityUtils - activesupport-4.2.4 Documentation

# module ActiveSupport::SecurityUtils

### Public Class Methods

secure_compare(a, b) click to toggle source

Constant time string comparison.

The values compared should be of fixed length, such as strings that have already been processed by HMAC. This should not be used on variable length plaintext strings because it could leak length info via timing attacks.

    # File lib/active_support/security_utils.rb, line 9
    def secure_compare(a, b)
      return false unless a.bytesize == b.bytesize

      l = a.unpack "C#{a.bytesize}"

      res = 0
      b.each_byte { |byte| res |= byte ^ l.shift }
      res == 0
    end

### Private Instance Methods

secure_compare(a, b) click to toggle source

Constant time string comparison.

The values compared should be of fixed length, such as strings that have already been processed by HMAC. This should not be used on variable length plaintext strings because it could leak length info via timing attacks.

    # File lib/active_support/security_utils.rb, line 9
    def secure_compare(a, b)
      return false unless a.bytesize == b.bytesize

      l = a.unpack "C#{a.bytesize}"

      res = 0
      b.each_byte { |byte| res |= byte ^ l.shift }
      res == 0
    end