def verify16!(one, two)
      check_length(one, 16, "First message")
      check_length(two, 16, "Second message")
      c_verify16(one, two)
    end
def verify16!(one, two)
      check_length(one, 16, "First message")
      check_length(two, 16, "Second message")
      c_verify16(one, two)
    end
Compare two 16 byte strings in constant time

 This should help to avoid timing attacks for string comparisons in your
 application.  Note that many of the functions (such as OneTime#verify)
 use this method under the hood already.

 @param [String] one String #1
 @param [String] two String #2

 @raise [ArgumentError] If the strings are not equal in length

 @return [Boolean] Well, are they equal?