Schneier on Security

This essay appeared as the second half of a point/counterpoint with Marcus Ranum.

The whitelist/blacklist debate is far older than computers, and it’s instructive to recall what works where. Physical security works generally on a whitelist model: if you have a key, you can open the door; if you know the combination, you can open the lock. We do it this way not because it’s easier—although it is generally much easier to make a list of people who should be allowed through your office door than a list of people who shouldn’t—but because it’s a security system that can be implemented automatically, without people…

This essay appeared as the first half of a point-counterpoint with Marcus Ranum. Marcus’s half is here.

In 2003, a group of security experts—myself included—published a paper saying that 1) software monocultures are dangerous and 2) Microsoft, being the largest creator of monocultures out there, is the most dangerous. Marcus Ranum responded with an essay that basically said we were full of it. Now, eight years later, Marcus and I thought it would be interesting to revisit the debate.

The basic problem with a monoculture is that it’s all vulnerable to the same attack. The Irish Potato Famine of 1845—9 is perhaps the most famous monoculture-related disaster. The Irish planted only one variety of potato, and the genetically identical potatoes succumbed to a rot caused by Phytophthora infestans. Compare that with the diversity of potatoes traditionally grown in South America, each one adapted to the particular soil and climate of its home, and you can see the security value in heterogeneity…

This essay appeared as the second half of a point/counterpoint with Marcus Ranum.

If you’re a typical wired American, you’ve got a bunch of tech tools you like and a bunch more you covet. You have a cell phone that can easily text. You’ve got a laptop configured just the way you want it. Maybe you have a Kindle for reading, or an iPad. And when the next new thing comes along, some of you will line up on the first day it’s available.

So why can’t work keep up? Why are you forced to use an unfamiliar, and sometimes outdated, operating system? Why do you need a second laptop, maybe an older and clunkier one? Why do you need a second cell phone with a new interface, or a BlackBerry, when your phone already does e-mail? Or a second BlackBerry tied to corporate e-mail? Why can’t you use the cool stuff you already have?…

This essay previously appeared in Information Security as the first half of a point-counterpoint with Marcus Ranum. Marcus’s half is here.

Any essay on hiring hackers quickly gets bogged down in definitions. What is a hacker, and how is he different from a cracker? I have my own definitions, but I’d rather define the issue more specifically: Would you hire someone convicted of a computer crime to fill a position of trust in your computer network? Or, more generally, would you hire someone convicted of a crime for a job related to that crime?…

This essay appeared as the second half of a point/counterpoint with Marcus Ranum. Marcus’s half is here.

Security is never black and white. If someone asks, “for best security, should I do A or B?” the answer almost invariably is both. But security is always a trade-off. Often it’s impossible to do both A and B—there’s no time to do both, it’s too expensive to do both, or whatever—and you have to choose. In that case, you look at A and B and you make you best choice. But it’s almost always more secure to do both.

Yes, antivirus programs have been getting less effective…