Entries Tagged "cryptography"
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Hacking Brain-Computer Interfaces
In this fascinating piece of research, the question is asked: can we surreptitiously collect secret information from the brains of people using brain-computer interface devices? One article:
A team of security researchers from Oxford, UC Berkeley, and the University of Geneva say that they were able to deduce digits of PIN numbers, birth months, areas of residence and other personal information by presenting 30 headset-wearing subjects with images of ATM machines, debit cards, maps, people, and random numbers in a series of experiments. The paper, titled “On the Feasibility of Side-Channel Attacks with Brain Computer Interfaces,” represents the first major attempt to uncover potential security risks in the use of the headsets.
This is a new development in spyware.
EDITED TO ADD (9/6): More articles. And here’s a discussion of the pros and cons of this sort of technology.
Is iPhone Security Really this Good?
Simson Garfinkel writes that the iPhone has such good security that the police can’t use it for forensics anymore:
Technologies the company has adopted protect Apple customers’ content so well that in many situations it’s impossible for law enforcement to perform forensic examinations of devices seized from criminals. Most significant is the increasing use of encryption, which is beginning to cause problems for law enforcement agencies when they encounter systems with encrypted drives.
“I can tell you from the Department of Justice perspective, if that drive is encrypted, you’re done,” Ovie Carroll, director of the cyber-crime lab at the Computer Crime and Intellectual Property Section in the Department of Justice, said during his keynote address at the DFRWS computer forensics conference in Washington, D.C., last Monday. “When conducting criminal investigations, if you pull the power on a drive that is whole-disk encrypted you have lost any chance of recovering that data.”
Yes, I believe that full-disk encryption—whether Apple’s FileVault or Microsoft’s BitLocker (I don’t know what the iOS system is called)—is good; but its security is only as good as the user is at choosing a good password.
The iPhone always supported a PIN lock, but the PIN wasn’t a deterrent to a serious attacker until the iPhone 3GS. Because those early phones didn’t use their hardware to perform encryption, a skilled investigator could hack into the phone, dump its flash memory, and directly access the phone’s address book, e-mail messages, and other information. But now, with Apple’s more sophisticated approach to encryption, investigators who want to examine data on a phone have to try every possible PIN. Examiners perform these so-called brute-force attacks with special software, because the iPhone can be programmed to wipe itself if the wrong PIN is provided more than 10 times in a row. This software must be run on the iPhone itself, limiting the guessing speed to 80 milliseconds per PIN. Trying all four-digit PINs therefore requires no more than 800 seconds, a little more than 13 minutes. However, if the user chooses a six-digit PIN, the maximum time required would be 22 hours; a nine-digit PIN would require 2.5 years, and a 10-digit pin would take 25 years. That’s good enough for most corporate secrets—and probably good enough for most criminals as well.
Leaving aside the user practice questions—my guess is that very few users, even those with something to hide, use a ten-digit PIN—could this possibly be true? In the introduction to Applied Cryptography, almost 20 years ago, I wrote: “There are two kinds of cryptography in this world: cryptography that will stop your kid sister from reading your files, and cryptography that will stop major governments from reading your files.”
Since then, I’ve learned two things: 1) there are a lot of gradients to kid sister cryptography, and 2) major government cryptography is very hard to get right. It’s not the cryptography; it’s everything around the cryptography. I said as much in the preface to Secrets and Lies in 2000:
Cryptography is a branch of mathematics. And like all mathematics, it involves numbers, equations, and logic. Security, palpable security that you or I might find useful in our lives, involves people: things people know, relationships between people, people and how they relate to machines. Digital security involves computers: complex, unstable, buggy computers.
Mathematics is perfect; reality is subjective. Mathematics is defined; computers are ornery. Mathematics is logical; people are erratic, capricious, and barely comprehensible.
If, in fact, we’ve finally achieved something resembling this level of security for our computers and handheld computing devices, this is something to celebrate.
But I’m skeptical.
Another article.
Slashdot has a thread on the article.
EDITED TO ADD: More analysis. And Elcomsoft can crack iPhones.
Help Cryptanalyze Gauss
Kaspersky is looking for help decrypting the Gauss payload.
Breaking Microsoft's PPTP Protocol
Some things never change. Thirteen years ago, Mudge and I published a paper breaking Microsoft’s PPTP protocol and the MS-CHAP authentication system. I haven’t been paying attention, but I presume it’s been fixed and improved over the years. Well, it’s been broken again.
ChapCrack can take captured network traffic that contains a MS-CHAPv2 network handshake (PPTP VPN or WPA2 Enterprise handshake) and reduce the handshake’s security to a single DES (Data Encryption Standard) key.
This DES key can then be submitted to CloudCracker.com—a commercial online password cracking service that runs on a special FPGA cracking box developed by David Hulton of Pico Computing—where it will be decrypted in under a day.
The CloudCracker output can then be used with ChapCrack to decrypt an entire session captured with WireShark or other similar network sniffing tools.
Cryptanalyze the Agrippa Code
William Gibson’s Agrippa Code is available for cryptanalysis. Break the code, win a prize.
EDITED TO ADD (7/17): The code has been broken.
So You Want to Be a Security Expert
I regularly receive e-mail from people who want advice on how to learn more about computer security, either as a course of study in college or as an IT person considering it as a career choice.
First, know that there are many subspecialties in computer security. You can be an expert in keeping systems from being hacked, or in creating unhackable software. You can be an expert in finding security problems in software, or in networks. You can be an expert in viruses, or policies, or cryptography. There are many, many opportunities for many different skill sets. You don’t have to be a coder to be a security expert.
In general, though, I have three pieces of advice to anyone who wants to learn computer security.
- Study. Studying can take many forms. It can be classwork, either at universities or at training conferences like SANS and Offensive Security. (These are good self-starter resources.) It can be reading; there are a lot of excellent books out there—and blogs—that teach different aspects of computer security out there. Don’t limit yourself to computer science, either. You can learn a lot by studying other areas of security, and soft sciences like economics, psychology, and sociology.
- Do. Computer security is fundamentally a practitioner’s art, and that requires practice. This means using what you’ve learned to configure security systems, design new security systems, and—yes—break existing security systems. This is why many courses have strong hands-on components; you won’t learn much without it.
- Show. It doesn’t matter what you know or what you can do if you can’t demonstrate it to someone who might want to hire you. This doesn’t just mean sounding good in an interview. It means sounding good on mailing lists and in blog comments. You can show your expertise by making podcasts and writing your own blog. You can teach seminars at your local user group meetings. You can write papers for conferences, or books.
I am a fan of security certifications, which can often demonstrate all of these things to a potential employer quickly and easily.
I’ve really said nothing here that isn’t also true for a gazillion other areas of study, but security also requires a particular mindset—one I consider essential for success in this field. I’m not sure it can be taught, but it certainly can be encouraged. “This kind of thinking is not natural for most people. It’s not natural for engineers. Good engineering involves thinking about how things can be made to work; the security mindset involves thinking about how things can be made to fail. It involves thinking like an attacker, an adversary or a criminal. You don’t have to exploit the vulnerabilities you find, but if you don’t see the world that way, you’ll never notice most security problems.” This is especially true if you want to design security systems and not just implement them. Remember Schneier’s Law: “Any person can invent a security system so clever that she or he can’t think of how to break it.” The only way your designs are going to be trusted is if you’ve made a name for yourself breaking other people’s designs.
One final word about cryptography. Modern cryptography is particularly hard to learn. In addition to everything above, it requires graduate-level knowledge in mathematics. And, as in computer security in general, your prowess is demonstrated by what you can break. The field has progressed a lot since I wrote this guide and self-study cryptanalysis course a dozen years ago, but they’re not bad places to start.
This essay originally appeared on “Krebs on Security,” the second in a series of answers to the question. This is the first. There will be more.
Al Qaeda Steganography
The reports are still early, but it seems that a bunch of terrorist planning documents were found embedded in a digital file of a porn movie.
Several weeks later, after laborious efforts to crack a password and software to make the file almost invisible, German investigators discovered encoded inside the actual video a treasure trove of intelligence—more than 100 al Qaeda documents that included an inside track on some of the terror group’s most audacious plots and a road map for future operations.
Alan Turing Cryptanalysis Papers
GCHQ, the UK government’s communications headquarters, has released two new—well, 70 years old, but new to us—cryptanalysis documents by Alan Turing.
The papers, one entitled The Applications of Probability to Crypt, and the other entitled Paper on the Statistics of Repetitions, discuss mathematical approaches to code breaking.
[…]
According to the GCHQ mathematician, who identified himself only as Richard, the papers detailed using “mathematical analysis to try and determine which are the more likely settings so that they can be tried as quickly as possible.”
The papers don’t seem to be online yet, but here’s their National Archives data.
EDITED TO ADD (5/12): The papers are available for download at GBP 3.50 each.
Summer Schools in Cryptography and Software Security at Penn State
Normally I just delete these as spam, but this summer program for graduate students 1) looks interesting, and 2) has some scholarship money available.
Sidebar photo of Bruce Schneier by Joe MacInnis.