Pencil-and-Paper Codes Used by Central American Criminal Gangs
No mention of how good the codes are. My guess is not very.
EDITED TO ADD (9/12): It’s a simple substitution cipher.
Entries Tagged "cryptography"
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The Security of al Qaeda Encryption Software
The web intelligence firm Recorded Future has posted two stories about how al Qaeda is using new encryption software in response to the Snowden disclosures. NPR picked up the story a week later.
Former NSA Chief Council Stewart Baker uses this as evidence that Snowden has harmed America. Glenn Greenwald calls this “CIA talking points” and shows that al Qaeda was using encryption well before Snowden. Both quote me heavily, Baker casting me as somehow disingenuous on this topic.
Baker is conflating my stating of two cryptography truisms. The first is that cryptography is hard, and you’re much better off using well-tested public algorithms than trying to roll your own. The second is that cryptographic implementation is hard, and you’re much better off using well-tested open-source encryption software than you are trying to roll your own. Admittedly, they’re very similar, and sometimes I’m not as precise as I should be when talking to reporters.
This is what I wrote in May:
I think this will help US intelligence efforts. Cryptography is hard, and the odds that a home-brew encryption product is better than a well-studied open-source tool is slight. Last fall, Matt Blaze said to me that he thought that the Snowden documents will usher in a new dark age of cryptography, as people abandon good algorithms and software for snake oil of their own devising. My guess is that this an example of that.
Note the phrase “good algorithms and software.” My intention was to invoke both truisms in the same sentence. That paragraph is true if al Qaeda is rolling their own encryption algorithms, as Recorded Future reported in May. And it remains true if al Qaeda is using algorithms like my own Twofish and rolling their own software, as Recorded Future reported earlier this month. Everything we know about how the NSA breaks cryptography is that they attack the implementations far more successfully than the algorithms.
My guess is that in this case they don’t even bother with the encryption software; they just attack the users’ computers. There’s nothing that screams “hack me” more than using specially designed al Qaeda encryption software. There’s probably a QUANTUMINSERT attack and FOXACID exploit already set on automatic fire.
I don’t want to get into an argument about whether al Qaeda is altering its security in response to the Snowden documents. Its members would be idiots if they did not, but it’s also clear that they were designing their own cryptographic software long before Snowden. My guess is that the smart ones are using public tools like OTR and PGP and the paranoid dumb ones are using their own stuff, and that the split was the same both pre- and post-Snowden.
The Simple Trick that Will Keep You Secure from Government Spies
Last week, the German government arrested someone and charged him with spying for the US. Buried in one of the stories was a little bit of tradecraft. The US gave him an encryption program embedded in a—presumably common—weather app. When you select the weather for New York, it automatically opens a crypto program. I assume this is a custom modification for the agent, and probably other agents as well. No idea how well this program was hidden. Was the modified weather app the same size as the original? Would it pass an integrity checker?
Related: there is an undocumented encryption feature in my own Password Safe program. From the command line, type: pwsafe -e filename
Defending Against Algorithm Substitution Attacks
Interesting paper: M. Bellare, K. Paterson, and P. Rogaway, “Security of Symmetric Encryption against Mass Surveillance.”
Abstract: Motivated by revelations concerning population-wide surveillance of encrypted communications, we formalize and investigate the resistance of symmetric encryption schemes to mass surveillance. The focus is on algorithm-substitution attacks (ASAs), where a subverted encryption algorithm replaces the real one. We assume that the goal of “big-brother” is undetectable subversion, meaning that ciphertexts produced by the subverted encryption algorithm should reveal plaintexts to big-brother yet be indistinguishable to users from those produced by the real encryption scheme. We formalize security notions to capture this goal and then offer both attacks and defenses. In the first category we show that successful (from the point of view of big brother) ASAs may be mounted on a large class of common symmetric encryption schemes. In the second category we show how to design symmetric encryption schemes that avoid such attacks and meet our notion of security. The lesson that emerges is the danger of choice: randomized, stateless schemes are subject to attack while deterministic, stateful ones are not.
Advances in Solving the Discrete Log Problem
At Eurocrypt this year, researchers presented a paper that completely breaks the discrete log problem in any field with a small characteristic. It’s nice work, and builds on a bunch of advances in this direction over the last several years. Despite headlines to the contrary, this does not have any cryptanalytic application—unless they can generalize the result, which seems unlikely to me.
New Al Qaeda Encryption Software
The Web intelligence company Recorded Future is reporting—picked up by the Wall Street Journal—that al Qaeda is using new encryption software in the wake of the Snowden stories. I’ve been fielding press queries, asking me how this will adversely affect US intelligence efforts.
I think the reverse is true. I think this will help US intelligence efforts. Cryptography is hard, and the odds that a home-brew encryption product is better than a well-studied open-source tool is slight. Last fall, Matt Blaze said to me that he thought that the Snowden documents will usher in a new dark age of cryptography, as people abandon good algorithms and software for snake oil of their own devising. My guess is that this an example of that.
A New Pencil-and-Paper Encryption Algorithm
Handycipher is a new pencil-and-paper symmetric encryption algorithm. I’d bet a gazillion dollars that it’s not secure, although I haven’t done the cryptanalysis myself.
Auditing TrueCrypt
Recently, Matthew Green has been leading an independent project to audit TrueCrypt. Phase I, a source code audit by iSEC Partners, is complete. Next up is Phase II, formal cryptanalysis.
Quick summary: I’m still using it.
"Unbreakable" Encryption Almost Certainly Isn't
This headline is provocative: “Human biology inspires ‘unbreakable’ encryption.”
The article is similarly nonsensical:
Researchers at Lancaster University, UK have taken a hint from the way the human lungs and heart constantly communicate with each other, to devise an innovative, highly flexible encryption algorithm that they claim can’t be broken using the traditional methods of cyberattack.
Information can be encrypted with an array of different algorithms, but the question of which method is the most secure is far from trivial. Such algorithms need a “key” to encrypt and decrypt information; the algorithms typically generate their keys using a well-known set of rules that can only admit a very large, but nonetheless finite number of possible keys. This means that in principle, given enough time and computing power, prying eyes can always break the code eventually.
The researchers, led by Dr. Tomislav Stankovski, created an encryption mechanism that can generate a truly unlimited number of keys, which they say vastly increases the security of the communication. To do so, they took inspiration from the anatomy of the human body.
Regularly, someone from outside cryptography—who has no idea how crypto works—pops up and says “hey, I can solve their problems.” Invariably, they make some trivial encryption scheme because they don’t know better.
Remember: anyone can create a cryptosystem that he himself cannot break. And this advice from 15 years ago is still relevant.
Sidebar photo of Bruce Schneier by Joe MacInnis.