Module: SecureEquals

Defined in:
lib/secure_equals.rb

Class Method Summary collapse

Class Method Details

.equal?(mine, theirs) ⇒ Boolean

Provides an equality method on strings that is not vulnerable to timing attacks.

This prevents attackers from being able to guess the answer byte-by-byte using tiny differences in response time.

Parameters:

  • The (String) —

    secret string

  • The (String) —

    string provided by the user

Returns:

  • (Boolean) —

    Are the strings the same?



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# File 'lib/secure_equals.rb', line 11

def self.equal?(mine, theirs)
  return false if mine.nil? || theirs.nil?
  mine = mine.to_str
  theirs = theirs.to_str
  return false unless mine.length == theirs.length

  difference = 0
  0.upto(mine.length - 1) do |i|
    difference |= (mine[i].ord ^ theirs[i].ord)
  end

  difference == 0
end