July 3, 2022

Archives for October 2004

New EVoting-Experts Group Blog

evoting-experts.com is a new group blog devoted to e-voting issues. Members include leading experts on the technology, including David Dill, Ed Felten, Joe Hall, Avi Rubin, Adam Stubblefield, and Dan Wallach (with more to come, we hope).

The site’s goal is to provide one-stop shopping for e-voting news and analysis, to the public and the press, on election day and thereafter.

Check it out, and please help us spread the word about the site.

The Big-Head Principle

Over the next few days, Americans will be asking themselves which candidate has what it takes to be president, or at least which one has what it takes to win the election. To answer this question, we must first determine exactly what it does take. Based on personal observation, I think I may know.

Bill Clinton is the only U.S. president I have seen up close. He walked about ten feet from me in the Princeton graduation procession a few years ago. And I couldn’t help noticing that he had a really big head. When I say this, I don’t mean he was very smart, and I don’t mean he had an inflated opinion of himself – though both of those things may well be true. I mean, quite literally, that his head was considerably larger than average for a man of his size. So much so that his head size is the one and only thing I remember about my near-encounter with him. Perhaps having a large head helps one to succeed in politics.

If you think about it, we are often drawn to big-headed creatures. Mickey Mouse. Frankenstein’s monster. Barney the dinosaur. Bart Simpson. Mister Potato Head. Spongebob Squarepants. What is it about big-heads that makes us want to watch them?

Perhaps the explanation is that babies have disproportionately large heads, and we are genetically programmed to like babies. Or perhaps large heads can better show sympathetic emotion.

In any case, head size is clearly an important factor in politics, a factor we can use to divine a hidden law of American politics – the candidate with the bigger head usually wins. Call it the Big-Head Principle.

Which candidate has the bigger head in this election? Video coverage shows the candidates shaking hands after the debates. Looking at the two men side by side, in the same shot, it’s clear that John Kerry has the bigger head.

Being nonpartisan, we will not endorse a candidate; but we can make a prediction. According to the Big-Head Principle, John Kerry will be the next president of the United States.

CallerID and Bad Authentication

A new web service allows anybody to make phone calls with forged CallerID (for a fee), according to a Kevin Poulsen story at SecurityFocus. (Another such service had been open briefly a few months ago.) This isn’t surprising, given the known insecurity of the CallerID system, which trusts the system where a call originates to provide accurate information about the calling number.

This is more than just a prankster’s delight, since some technologies are designed to use CallerID as if it were a secure identifier of the calling number. Poulsen reports, for instance, that T-Mobile uses CallerID to authenticate its customers’ access to their voicemail. If I can call the T-Mobile voicemail system, while sending CallerID information indicating that the call is coming from your phone, then I can access your voicemail box.

Needless to say, it’s a bad idea to use an insecure identifier to authenticate accesses to any service. Still, this mistake is often made.

A common example of the same mistake is to use IP addresses (the numeric addresses that designate “places” on the Internet) to authenticate users of an Internet service. For example, if Princeton University subscribes to some online database, the database service may allow access from any of the IP addressess belonging to Princeton. This is a bad idea, since IP addresses can sometimes be spoofed and various legitimate services can make an access seem to come from one address when it’s really coming from another.

If I were to run a web proxy within the Princeton network, then anybody accessing the web through my proxy might (depending on the circumstances) appear to be using a Princeton IP address. My web proxy might therefore allow anybody on the web to access the proprietary database. Some users might deliberately use my proxy to gain unauthorized access, and some users might be using the proxy for other, legitimate reasons and be surprised to have open access to the database. In either case, the access would be enabled by the database company’s decision to rely on IP addresses to control access.

In practice, people who design web proxies and similar services often find themselves jumping through hoops to try to prevent this kind of problem, even though it’s not their fault. One isn’t supposed to rely on IP addresses for authentication, but many people do. The result is that developers of new services may find themselves either (a) inadvertently enabling unauthorized access to other services, or (b) spending extra time and effort to shore up the insecure systems of others. Some of my colleagues who developed CoDeeN, a cool distributed web proxy system, found themselves wrestling with this problem and ultimately chose to add complexity to their design to protect some IP-address-based authentication systems. (They wrote an interesting paper about all of the “bad traffic” that showed up when they set up CoDeeN.)

It will be interesting to see how the CallerID story develops. My guess is that people will stop relying on the accuracy of CallerID, as spoofing becomes more widespread.