February 20, 2018

Archives for 2010

Smart electrical meters and their smart peripherals

When I was a college undergraduate, I lived in a 1920’s duplex and I recall my roommate and I trying to figure out where our electrical bill was going. He was standing outside by the electrical meter, I was turning things on and off, and we were yelling back and forth so we could sort out which gadgets were causing the wheel to spin faster. (The big power sinks? Our ancient 1950’s refrigerator and my massive-for-the-day 20-inch computer monitor.) Needless to say, this was more difficult than it should have been.

More recently, I got myself a Kill-a-Watt inline power meter which you can use at any power outlet, but it’s a pain. You have to unplug something to measure its usage. People with the big bucks will spring for a Ted 5000 system, which an electrician installs in your breaker box. That’s fantastic, but it’s not cheap or easy.

Today, I’m now the proud new owner of an LS Research “RateSaver”, which speaks ZigBee wireless to the “smart meter” that CenterPoint Energy installed on all the houses in our area. How did I get this thing? I went to a League of Women Voters “meet the candidates” event back in October and CenterPoint Energy had a display there. I asked the guy if I could get one of these things and he said he’s look into it for me. Fast forward two months later, and a box arrived in the mail. New toy!

So what exactly is it? It’s a battery-powered light-weight box with a tolerably readable two-inch monochrome LCD display. As I’m sitting here typing, it’s updating my “current usage” every few seconds and is giving me a number that’s ostensibly accurate to the watt. In the last minute, after I pressed the proper button, it’s been alternating between reading 650-750 watts, and 1400-1500 watts. (Hmm… maybe my fridge consumes 700 watts.) If you leave it alone, the refresh rate slows down to maybe once a minute. Also, it’s sometimes reading “0.000 kW” which is clearly incorrect but it returns to the proper number when I press the button. Wireless range is quite good. I’m on the opposite side of the house as our electrical meter and it’s working fine.

The user interface is all kinds of terrible. In addition to slow button response, the button labels are incorrect. LS Research is apparently just rebranding a Honeywell Home Energy Display (for which the Honeywell manual was included). LS Research apparently rearranged the button labels without changing the corrresponding software. Bravo! Thankfully, the Honeywell manuals have the proper labeling. Also amusing: there’s a message in the system saying that “non-peak price starts at 7:00 PM. Save Money by waiting” when in fact my electrical pricing deal is for a flat rate (which floats with market conditions and is presently $0.0631 per kWh).

Update: I’ve since learned that Honeywell acquired LS Research, so this is something of a transitional screw-up. Welcome to the world of beta products.

Since I’m a security guy, I assumed I’d have to go through some kind of protocol to get the thing activated, and the manual from inside the box describes an activation procedure where you make a phone call to your energy company, giving them the hardware ID numbers of the outdoor smart meter and the indoor display box. Conflicting instructions were also included with my display, describing setup which was as simple as “turn it on and hit the connect button” so I went with the easy instructions. Time passed and the box started working without requiring any additional input from me. I hope that my display box was pre-configured to work exclusively with my house, but this does lead me to wonder about whether they got the security right. (I experimentally turned lights on and off while watching the meter updates and validated that I am, in fact, looking at the usage of my own house.)

At the end of the day, I and everybody else here is now required to pay a $3.24 “advanced meter charge” in order to have all this functionality (which, incidentally, saves the electric company money since it no longer needs human meter readers). Is it worth it? Presumably, at some point I’ll have some kind of variable-priced electricity and I could then hack my refrigerator and air conditioning system to pay attention to the spot price of electricity. If electricity got extra cheap during a five minute window of the hot summer, the controller could then crank the A/C and drop the house an extra few degrees. Of course, if everybody was following this same algorithm, you’d either have insane demand swings, when everybody jumps on to consume cheaper electricity when it’s available, or you’d have to carefully engineer the pricing system such that you had stable demand. Presumably, if you got somebody who understood control theory to design this properly, you could end up incentivizing both demand and pricing to be fairly stable across the space of any given hour of the day.

Probably the biggest benefit of these smart meters will come the next time we have a major hurricane that comes through and knocks out power. Hurricane Ike left my house without power for ten days. At the time, CenterPoint Energy had a vague and useless web site that would give you an idea what neighborhoods were being repaired. Since it was too hot to stay in our house, we stayed instead with a friend who had power and drove by our place every day to see if it had power. This was very frustrating. (I unplugged all my computer equipment, since I didn’t want flakey power to nuke my equipment. Consequently, I couldn’t just do something simple like ping my home computer.) Today, I can log into CenterPoint Energy’s web site and see the power consumption of my house, in 15-minute intervals, and so can the people coordinating the repairs. If they integrated that with a mapping system, they’d have real-time blackout maps, which have obvious value to emergency planners and repair operations coordination.

I just hope they have somebody with a clue looking over the security of their system. (If somebody from CenterPoint reads this: people like me are more than happy to do private security evaluations, red-team exercises, and so forth.)

Future work: there’s a mini USB port on the side of the box. Now I just have to find some documentation. It’s probably bad form for me to go reverse-engineer it myself.

Unpeeling the mystique of tamper-indicating seals

As computer scientists have studied the trustworthiness of different voting technologies over the past decade, we notice that “security seals” are often used by election officials. It’s natural to wonder whether they really provide any real security, or whether they are just for show. When Professor Avi Rubin volunteered as an election judge (Marylandese for pollworker) in 2006, one of his observations that I found most striking was this:

Avi Rubin

“For example, I carefully studied the tamper tape that is used to guard the memory cards. In light of Hursti’s report, the security of the memory cards is critical. Well, I am 100% convinced that if the tamper tape had been peeled off and put back on, nobody except a very well trained professional would notice it. The tamper tape has a tiny version of the word “void” appear inside it after it has been removed and replaced, but it is very subtle. In fact, a couple of times, due to issues we had with the machines, the chief judge removed the tamper tape and then put it back. One time, it was to reboot a machine that was hanging when a voter was trying to vote. I looked at the tamper tape that was replaced and couldn’t tell the difference, and then it occurred to me that instead of rebooting, someone could mess with the memory card and replace the tape, and we wouldn’t have noticed. I asked if I could play with the tamper tape a bit, and they let me handle it. I believe I can now, with great effort and concentration, tell the difference between one that has been peeled off and one that has not. But, I did not see the judges using that kind of care every time they opened and closed them. As far as I’m concerned, the tamper tape does very little in the way of actual security, and that will be the case as long as it is used by lay poll workers, as opposed to CIA

Avi is a first-rate expert in the field of computer security, in part because he’s a good experimentalist—as in, “I asked if I could play with the tamper tape.” To the nonexpert,
security seals have a mystique: there’s this device there, perhaps a special tape or perhaps a thing that looks like a little blue plastic padlock. Most of us encounter these devices in a context where we can’t “play with” them, because that would be breaking the rules: on voting machines, on our electric meter, or whatever. Since we don’t play with them, we can’t tell whether they are secure, and the mystique endures. As soon
as Avi played with one, he discovered that it’s not all that secure.

In fact, we have a word for a piece of tape that only gives the appearance of working:

band-aid: (2) a temporary way of dealing with a problem that will not really solve it (Macmillan Dictionary)

In the last couple of years I’ve been studying security seals on voting machines in New Jersey. For many decades New Jersey law has required that each voting machine be “sealed with a numbered seal”, just after it is prepared for each election (NJSA 19:48-6). Unfortunately it’s hard for legislators to write into the statutes exactly how well these seals must work. Are tamper-indicating seals used in elections really secure? I’ll address that question in my next few articles.

Trying to Make Sense of the Comcast / Level 3 Dispute

[Update: I gave a brief interview to Marketplace Tech Report]

The last 48 hours has given rise to a fascinating dispute between Level 3 (a major internet backbone provider) and Comcast (a major internet service retailer). The dispute involves both technical principles and fuzzy facts, so I am writing this post more as an attempt to sort out the details in collaboration with commenters than as a definitive guide. Before we get to the facts, let’s define some terms:

Internet Backbone Provider: These are companies, like Level 3, that transport the majority of the traffic at the core of the Internet. I say the “core” because they don’t typically provide connections to the general public, and they do the majority of their routing using the Border Gateway Protocol (BGP) and deliver traffic from one Autonomous System (AS) to another. Each backbone provider is its own AS, but so are Internet Service Retailers. Backbone providers will often agree to “settlement free peering with each other in which they deliver each others’ traffic for no fee.

Internet Service Retailers: These are companies that build the “last mile” of internet infrastructure to the general public and sell service. I’ve called them “Retailers” even though most people have traditionally called them Internet Service Providers (the ISP term can get confusing). Retailers sign up customers with the promise of connecting them to the backbone, and then sign “transit” agreements to pay the backbone providers for delivering the traffic that their customers request.

Content Delivery Networks: These are companies like Akamai that provide an enhanced service compared to backbone providers because they specialize in physically locating content closer to the edges (such that many copies of the content are stored in a part of the network that is closer to end-users). The benefit of this is that the content is theoretically faster and more reliable for end-users to access because it has to traverse less “hops.” CDNs will often sign agreements with Retailers to interconnect at many locations that are close to the end-users, and even to rent space to put their servers in the Retailer’s facilities (a practice called co-location).

Akamai and LimeLight Networks have traditionally provided delivery of Netflix content to Comcast customers as CDNs, and paid Comcast for local interconnection and colocation. Level 3, on the other hand, has a longstanding transit agreement with Comcast in which Comcast pays Level 3 to provide its customers with access to the internet backbone. Level 3 signed a deal with Netflix to become the primary provider of their content instead of the existing CDNs. Rather than change its business relationship with Comcast to something more akin to a CDN, in which it pays to locally interconnect and colocate, Level 3 hoped to continue to be paid by Comcast for providing backbone connectivity for its customers. Evidently, it thought that the current terms of its transit agreement with Comcast provided sufficient speed and reliability to satisfy Netflix. Comcast realized that they would simultaneously be losing the revenue from the existing CDNs that paid them for local services, and it would have to pay Level 3 more for backbone connectivity because more traffic would be traversing those links (apparently a whole lot). Comcast decided to try to instead charge Level 3, which didn’t sound like a good deal to Level 3. Level 3 published a press release saying Comcast was trying to unfairly leverage their exclusive control of end-users. Comcast sent a letter to the FCC saying that nothing unfair was going on and this was just a run-of-the-mill peering dispute. Level 3 replied that it was no such thing. [Updates: Comcast told the FCC that they they really do originate a lot of traffic and should be considered a backbone provider. Level 3 released their own FAQ, discussing the peering issue as well as the competitive issues. AT&T blogged in support of Comcast, Level 3 said that AT&T “missed the point completely.”]

Comcast’s attempt to describe the dispute as something akin to a peering dispute between backbone providers strikes me as misleading. Comcast is not a backbone provider that can deliver packets to an arbitrary location on the internet (a location that many other backbone providers might also be able to deliver to). Instead, Comcast is representing only its end-users, and it is doing so exclusively. What’s more, it has never had a settlement-free peering agreement with Level 3 (always transit, with Comcast paying). [Edit: see my clarification below in which I raise the possibility that it may have had both agreements at the same time, but relating to different traffic.] Indeed, the very nature of retail broadband service is that download quantity (or the traffic going into the Comcast AS) far exceeds upload quantity. In Comcast’s view of the world, therefore, all of their transit agreements should be reversed such that the backbone providers pay them for the privilege of reaching their users.

Why is this a problem? Won’t the market sort it out? First, the backbone market is still relatively competitive, and within that market I think that economic forces stand a reasonable chance of finding the optimal efficiency and leave relatively less room for anti-competitive shenanigans. However, these market dynamics can fall apart when you add to the mix last-mile providers. Last mile providers by their nature have at least a temporary monopoly on serving a given customer and often (in the case of a provider like Comcast) a local near-monopoly on high-performance broadband service altogether. Historically, the segmentation between the backbone market and the last-mile market has prevented shenanigans in the latter from seeping into the former. Two significant changes have occurred that alter this balance: 1) Comcast has grown to the size that it exerts tremendous power over a large portion of the broadband retail customers, with far less competition than in the past (for example the era of dial-up) and 2) Level 3 has sought to become the exclusive provider of certain desirable online content, but without the same network and business structure as traditional CDNs.

The market analysis becomes even more complicated in a scenario in which the last-mile provider has a vertically integrated service that competes with services being provided over the backbone provider with which it interconnects. Comcast’s basic video service clearly competes with Netflix and other internet video. In addition, Comcast’s TV Everywhere service (in partnership with HBO) competes with other computer-screen on-demand video services. Finally, the pending Comcst/NBCU merger (under review by the FCC and DoJ) implicates Hulu and a far greater degree of vertical integration with content providers. This means that in addition to its general incentives to price-squeeze backbone providers, Comcast clearly has incentive to discriminate against other online video providers (either by altering speed or by charging more than what a competitive market would yield).

But what do you all think? You may also find it worthwhile to slog through some of the traffic on the NANOG email list, starting roughly here.

[Edit: I ran across this fascinating blog post on the issue by Global Crossing, a backbone provider similar to Level 3.]

[Edit: Take a look at this fantastic overview of the situation in a blog post from Adam Rothschild.]