[E-voting] [OT] Trustworthy Breathalysers

Tim timod at esatclear.ie
Fri Oct 21 18:00:27 IST 2005

Kind of OT, yet kind of related.





Breathalyzers and Open Source
Friday October 21, 2005 by Edward W. Felten

Lawyers for 150 Floridians accused of drunk driving have asked a court to
order the disclosure of the source code for software running in the
breathalyzer machines used by police to analyze their blood alcohol level,
according to a Tom Sanders story on vunet.

The defendants say they have the right to examine the machines that accused
them, and that a meaningful examination requires access to the machines¹
software. Prosecutors say the code is a trade secret.

The accused are right that one needs the code to understand fully how the
machines work. The machines consist of sensors, a user interface, and
control software. The software is the ³brain² of the machine, and it is
almost certainly involved in the calculations that derive a blood alcohol
value from the sensor readings, as well as the display of the calculated
value. If the accused have the right to fully examine the machines ‹ and the
article says that they do under Florida law ‹ then they should see the
source code.

Contrary to the article and some other commentators, this is not a dispute
over whether the software should be open source. The accused aren¹t seeking
to open the software to everybody; they only want it opened to their legal

There are standard practices for handling trade-secret information that must
be turned over in court cases. A court will typically establish a protective
order, which is a kind of nondisclosure agreement covering secret material
that is turned over by one side to the other. The protective order will
require parties to keep the information secret and to use it only for
purposes related to the court proceedings. Typically the information can be
turned over to a limited number of expert analysts who have also signed the
protective order. Documents containing secret information are filed under
seal, and testimony about secret matters may take place in a closed

So this issue is not about open source, but about ensuring fairness for the
accused. If they¹re going to be accused based on what some machine says,
then they ought to be allowed to challenge the accuracy of the machine. And
they can¹t do that unless they¹re allowed to know how the machine works.

You might argue that the machine¹s technical manuals convey enough
information. Having read many manuals and examine the innards of many
software systems, I¹m skeptical of such claims. Often, knowing how the maker
says a machine works is a poor substitute for knowing how it actually works.
If a machine is flawed, it¹s likely the maker will either (a) not know about
the flaw or (b) be unwilling to admit it exists.

If the article¹s description of Florida law is correct, this seems like a
pretty easy decision for the court.

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