Privacy and Security

Security is a big focus in personal, server, and embedded computing.  Computer security or cybersecurity broadly refers to all sorts of information security.  We often focus on malicious attacks but good computer security offers protection against natural events as well.

Privacy is a related but distinct issue.  Computer privacy refers to what others can find out about us.  This of course includes what we tell the world and what information about us the bad guys can steal from our computers.  But privacy also includes what can be inferred from our data.  In a lot of cases, our agreement to release one kind of data allows others to infer more about us.

A good cyber-physical example of the nature of privacy is offered by your electric meter.  Your electric utility reads your meter periodically to bill you for the electricity you use.  But those meter readings tell more about what you do.  With even sparse electricity readings, such as the typical monthly reading, an observer can estimate the number of people living in your house.  I have heard rumors that some authoritarian regimes use just this technique to find people hiding in homes.  With more frequent readings, an observer could tell when you are likely to be away from the house.  This is the cyber-physical equivalent of the old thieves' trick of driving by to find houses with no lights, then targeting those houses for burglaries.

As we install more cyber-physical systems and IoT devices, we will create new privacy problems for ourselves.  Some of these are variations on old-world privacy issues; other problems are relatively novel.  Hopefully, we can roll out these systems so that we don't create long-lasting privacy holes that society can't easily plug.

More on IoT Security

Semiwiki.com has a number of interesting posts on the semiconductor industry and chip design.  Two recent posts address the intersection of chip design and the Internet-of-Things:

• Don Dingee described a technique for modifying one-time programmable keys.  He makes the very good point that a lot of devices whose data is identified with us may be sold or transferred, creating a potential security and privacy problem.
• Pawan Fangaria talks about the importance of MEMS sensors for IoT and discusses MEMS design techniques.

Internet of Things security

Proofpoint, a computer security company, has confirmed what we long suspected: Internet-of-things devices pose computer security threads.  Their article, which you can find here, describes how they found a variety of household Internet-connected devices were sending out malicious emails.  The offending devices included multimedia devices and "at least one refrigerator."

 The idea of refrigerators as sleeper agents or Skynet nodes may sound like a Saturday Night Live sketch, but this observation has some serious implications.  PC security, while far from perfect, is much better than it was 20 years ago.  IoT devices are at a primitive level, but unlike PCs, consumers often have no reason to worry about them.  Malware on PCs may be used to attack other computers, but everyday users understand the very real threat to their data that is posed by these programs.  As a result, consumers are willing to invest in computer security tools.  So long as malware on IoTs is used to attack other computers without seriously affecting the device, consumers are unlikely to care much that their refrigerator has become a zombie.  And the market for these devices is sufficiently cost-sensitive that manufacturers are unlikely to introduce strong security measures on their own.  Like so many things, it may take a disastrous event to wake people up to the problem.

787 Battery As A Cyber-Physical System

The problems with the 787 battery a year ago haven't recurred, thankfully.  So now is a good time to step back and think about the implications of this issue for cyber-physical system design.  Here are a few informational links:

• Aviation Week provided excellent coverage, including this description of battery testing and a photo of the damaged battery.
• Boeing's review of the battery certification process. 
• An interesting article from Avionics Magazine on the battery issue.

While the battery behavior itself is ultimately a chemistry issue that is far beyond my expertise, the root causes go back to cyber-physical system design.  During normal operation after the engines are started on the ground, the airplane's electric energy comes from the auxiliary power unit, a small jet engine driving an electric generator. The battery is provided in part as an emergency electricity source in case the main generator fails.  The 787 is a fly-by-wire aircraft, so the flight controls depend on electronics.  But the 787 goes well beyond minimal fly-by-wire to use a great deal of electronics that are important to the aircraft operation.  As a result, the battery needs to be able to supply a great deal of energy in some cases.  The battery technologies generally used in aircraft---and those that are generally approved under certification procedures---provide lower energy density than does the lithium battery technology used in the 787.  Energy density is very important in an airplane because weight is a critical factor in overall aircraft performance.  Aircraft designs must be certified.  Although lithium batteries had been used in certified aircraft design in a handful of cases, the 787 represented an early use of this type of battery.  The detailed design of the battery subsystem was driven by competing system constraints: on the one hand, weight; on the other hand, heavy use of electronics.