method

secure_compare

v5.0.0.1 - Show latest stable - 0 notes - Class: SecurityUtils

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What's this?

secure_compare(a, b) private

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.

Show source

# File activesupport/lib/active_support/security_utils.rb, line 11
    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

secure_compare

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