Entries Tagged "encryption"

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Al Qaeda Secret Code Broken

I would sure like to know more about this:

Top code-breakers at the Government Communications Headquarters in the United Kingdom have succeeded in breaking the secret language that has allowed imprisoned leaders of al-Qaida to keep in touch with other extremists in U.K. jails as well as 10,000 “sleeper agents” across the islands….

[…]

For six months, the code-breakers worked around the clock deciphering the code the three terrorists created.

Between them, the code-breakers speak all the dialects that form the basis for the code. Several of them have high-value skills in computer technology. The team worked closely with the U.S. National Security Agency and its station at Menwith Hill in the north of England. The identity of the code-breakers is so secret that not even their gender can be revealed.

“Like all good codes, the one they broke depended on substituting words, numbers or symbols for plain text. A single symbol could represent an idea or an entire message,” said an intelligence source.

The code the terrorists devised consists of words chosen from no fewer than 20 dialects from Afghanistan, Iran, Pakistan, Yemen and Sudan.

Inserted with the words ­ either before or after them ­ is local slang. The completed message is then buried in Islamic religious tracts.

EDITED TO ADD: Here’s a link to the story that still works. I didn’t realize this came from WorldNetDaily, so take it with an appropriate amount of salt.

Posted on November 23, 2009 at 7:24 AM • View Comments

Blowfish in Fiction

The algorithm is mentioned in Von Neumann’s War, by John Ringo and Travis Taylor.

P. 495:

The guy was using a fairly simple buffer overflow attack but with a very nice little fillip of an encryption packet designed to overcome Blowfish. The point seemed to be to create a zero day exploit, which he didn’t have a chance of managing. So far, nobody had cracked Blowfish.

P. 504:

As far as he could tell, at first, it was a simple Denial of Service attack. A DoS occurred when… But this one was different. Every single packet contained some sort of cracking program … Most had dumped to the honey trap, but they were running rampant through there, while others had managed to hammer past two firewalls and were getting to his final line of defense. Somebody had managed a zero day exploit on Blowfish. And more were coming in!

Posted on November 13, 2009 at 2:43 PM • View Comments

Mossad Hacked Syrian Official's Computer

It was unattended in a hotel room at the time:

Israel’s Mossad espionage agency used Trojan Horse programs to gather intelligence about a nuclear facility in Syria the Israel Defense Forces destroyed in 2007, the German magazine Der Spiegel reported Monday.

According to the magazine, Mossad agents in London planted the malware on the computer of a Syrian official who was staying in the British capital; he was at a hotel in the upscale neighborhood of Kensington at the time.

The program copied the details of Syria’s illicit nuclear program and sent them directly to the Mossad agents’ computers, the report said.

Remember the evil maid attack: if an attacker gets hold of your computer temporarily, he can bypass your encryption software.

Posted on November 5, 2009 at 12:48 PM • View Comments

"Evil Maid" Attacks on Encrypted Hard Drives

Earlier this month, Joanna Rutkowska implemented the “evil maid” attack against TrueCrypt. The same kind of attack should work against any whole-disk encryption, including PGP Disk and BitLocker. Basically, the attack works like this:

Step 1: Attacker gains access to your shut-down computer and boots it from a separate volume. The attacker writes a hacked bootloader onto your system, then shuts it down.

Step 2: You boot your computer using the attacker’s hacked bootloader, entering your encryption key. Once the disk is unlocked, the hacked bootloader does its mischief. It might install malware to capture the key and send it over the Internet somewhere, or store it in some location on the disk to be retrieved later, or whatever.

You can see why it’s called the “evil maid” attack; a likely scenario is that you leave your encrypted computer in your hotel room when you go out to dinner, and the maid sneaks in and installs the hacked bootloader. The same maid could even sneak back the next night and erase any traces of her actions.

This attack exploits the same basic vulnerability as the “Cold Boot” attack from last year, and the “Stoned Boot” attack from earlier this year, and there’s no real defense to this sort of thing. As soon as you give up physical control of your computer, all bets are off.

Similar hardware-based attacks were among the main reasons why Symantec’s CTO Mark Bregman was recently advised by “three-letter agencies in the US Government” to use separate laptop and mobile device when traveling to China, citing potential hardware-based compromise.

PGP sums it up in their blog.

No security product on the market today can protect you if the underlying computer has been compromised by malware with root level administrative privileges. That said, there exists well-understood common sense defenses against “Cold Boot,” “Stoned Boot” “Evil Maid,” and many other attacks yet to be named and publicized.

The defenses are basically two-factor authentication: a token you don’t leave in your hotel room for the maid to find and use. The maid could still corrupt the machine, but it’s more work than just storing the password for later use. Putting your data on a thumb drive and taking it with you doesn’t work; when you return you’re plugging your thumb into a corrupted machine.

The real defense here is trusted boot, something Trusted Computing is supposed to enable. But Trusted Computing has its own problems, which is why we haven’t seen anything out of Microsoft in the seven-plus years they have been working on it (I wrote this in 2002 about what they then called Palladium).

In the meantime, people who encrypt their hard drives, or partitions on their hard drives, have to realize that the encryption gives them less protection than they probably believe. It protects against someone confiscating or stealing their computer and then trying to get at the data. It does not protect against an attacker who has access to your computer over a period of time during which you use it, too.

EDITED TO ADD (10/23): A few readers have pointed out that BitLocker, the one thing that has come out of Microsoft’s Trusted Computing initiative in the seven-plus years they’ve been working on it, can prevent these sorts of attacks if the computer has a TPM module, version 1.2 or later, on the motherboard. (Note: Not all computers do.) I actually knew that; I just didn’t remember it.

EDITED TO ADD (11/12): Peter Kleissner’s Stoned Boot attacks on TrueCrypt.

EDITED TO ADD (12/9): A similar attack is possible against BitLocker with a TPM.

Posted on October 23, 2009 at 6:43 AM • View Comments

Australia Man Receives Reduced Sentence Due to Encryption

From the Courier-Mail:

A man who established a sophisticated network of peepholes and cameras to spy on his flatmates has escaped a jail sentence after police were unable to crack an encryption code on his home computer.

[…]

They found a series of holes drilled in to walls and ceilings throughout the Surfers Paradise apartment with wires leading back to Wyllie’s bedroom.

Police seized his personal computer, but files were encrypted and a video camera was not plugged in.

[…]

In passing sentence, Judge Devereaux took in to account the 33 days Wyllie had spent in custody after being arrested and ordered that two years’ probation was sufficient punishment, given that there was no hard evidence proving he had secretly recorded his flatmates.

Posted on October 21, 2009 at 7:19 AM • View Comments

The Doghouse: Privacy Inside

I’m just going to quote without comment:

About the file:
the text message file encrypted with a symmetric key combine 3 modes

1st changing the original text with random (white noise) and PHR (Pure Human Randomness) shuffle command , move and replace instruction combine with the key from mode 1 (white noise) and 2 (PHR)

2nd mode ­ xor PHR – Pure Human random ( or ROEE Random Oriented Enhanced Encryption) with a TIME set of instruction , and a computational temporary set of instructions to produce a real one time PAD when every time ,

Text will transform to a cipher the last will be different

3rd mode ­ xor WNS – White Noise Signal with a TIME set of instruction , and a computational temporary set of instructions to produce a real one time PAD when every time ,

Text will transform to a cipher the last will be different

4th Reconstructs file, levels and dimensions to a
this is a none mathematical with zero use of calculation algorithm – so no brute force , Rainbow Crack , or gpu cuda nvidia brute force crack can be applied on this technology . Sorry you have to find a new way to crack chaos theory for that.

We use 0% of any mathematical calculation algorithm ­ so we can perform any ware with unparalleled strength

Key Strength – 1million bit or more
Speed performance 400% faster Compeer to AES
MPU use – Mathematical Process Unit in CPU use 3% – 7% only
Overhead of the file from original 5% +/- (original+5%) +/-
A combination of mode 1 and 2 applied with a new variation of XOR – to perform the encrypted message

Anyone have any ideas?

Posted on October 13, 2009 at 2:55 PM • View Comments

The Doghouse: Crypteto

Crypteto has a 49,152-bit symmetric key:

The most important issue of any encryption product is the ‘bit key strength’. To date the strongest known algorithm has a 448-bit key. Crypteto now offers a
49,152-bit key. This means that for every extra 1 bit increase that Crypteto has over its competition makes it 100% stronger. The security and privacy this offers
is staggering.

Yes, every key bit doubles an algorithm’s strength against brute-force attacks. But it’s hard to find any real meaning in a work factor of 249152.

Coupled with this truly remarkable breakthrough Crypteto does not compromise on encryption speed. In the past, incremental key strength improvements have effected the speed that data is encrypted. The usual situation was that for every 1 bit increase in key strength there was a consequent reduction in encryption
speed by 50%.

That’s not even remotely true. It’s not at all obvious how key length is related to encryption speed. Blowfish has the same speed, regardless of key length. AES-192 is about 20% slower than AES-128, and AES-256 is about 40% slower. Threefish, the block cipher inside Skein, encrypts data at 7.6 clock cycles/byte with a 256-bit key, 6.1 clock cycles/byte with a 512-bit key, and 6.5 clock cycles/byte with a 1024-bit key. I’m not claiming that Threefish is secure and ready for commercial use—at any keylength—but there simply isn’t a chance that encryption speed will drop by half for every key bit added.

This is a fundamental asymmetry of cryptography, and it’s important to get right. The cost to encrypt is linear as a function of key length, while cost to break is geometric. It’s one of the reasons why, of all the links in a security chain, cryptography is the strongest.

Normally I wouldn’t bother with this kind of thing, but they explicitly asked me to comment:

But Hawthorne Davies has overcome this issue. By offering an algorithm with an unequalled key strength of 49,152 bits, we are able to encrypt and decrypt data at speeds in excess of 8 megabytes per second. This means that the aforementioned Gigabyte of data would take 2 minutes 13 seconds. If Bruce Schneier, the United State’s foremost cryptologist, were to increase his Blowfish 448 bit encryption algorithm to Blowfish 49152, he would be hard pressed to encrypt one Gigabyte in 4 hours.

[…]

We look forward to receiving advice and encouragement from the good Dr. Schneier.

I’m not a doctor of anything, but sure. Read my 1999 essay on snake-oil cryptography:

Warning Sign #5: Ridiculous key lengths.

Jaws Technology boasts: “Thanks to the JAWS L5 algorithm’s statistically unbreakable 4096 bit key, the safety of your most valued data files is ensured.” Meganet takes the ridiculous a step further: “1 million bit symmetric keys—The market offer’s [sic] 40-160 bit only!!”

Longer key lengths are better, but only up to a point. AES will have 128-bit, 192-bit, and 256-bit key lengths. This is far longer than needed for the foreseeable future. In fact, we cannot even imagine a world where 256-bit brute force searches are possible. It requires some fundamental breakthroughs in physics and our understanding of the universe. For public-key cryptography, 2048-bit keys have same sort of property; longer is meaningless.

Think of this as a sub-example of Warning Sign #4: if the company doesn’t understand keys, do you really want them to design your security product?

Or read what I wrote about symmetric key lengths in 1996, in Applied Cryptography (pp. 157–8):

One of the consequences of the second law of thermodynamics is that a certain amount of energy is necessary to represent information. To record a single bit by changing the state of a system requires an amount of energy no less than kT, where T is the absolute temperature of the system and k is the Boltzman constant. (Stick with me; the physics lesson is almost over.)

Given that k = 1.38×10-16 erg/°Kelvin, and that the ambient temperature of the universe is 3.2°Kelvin, an ideal computer running at 3.2°K would consume 4.4×10-16 ergs every time it set or cleared a bit. To run a computer any colder than the cosmic background radiation would require extra energy to run a heat pump.

Now, the annual energy output of our sun is about 1.21×1041 ergs. This is enough to power about 2.7×1056 single bit changes on our ideal computer; enough state changes to put a 187-bit counter through all its values. If we built a Dyson sphere around the sun and captured all its energy for 32 years, without any loss, we could power a computer to count up to 2192. Of course, it wouldn’t have the energy left over to perform any useful calculations with this counter.

But that’s just one star, and a measly one at that. A typical supernova releases something like 1051 ergs. (About a hundred times as much energy would be released in the form of neutrinos, but let them go for now.) If all of this energy could be channeled into a single orgy of computation, a 219-bit counter could be cycled through all of its states.

These numbers have nothing to do with the technology of the devices; they are the maximums that thermodynamics will allow. And they strongly imply that brute-force attacks against 256-bit keys will be infeasible until computers are built from something other than matter and occupy something other than space.

Ten years later, there is still no reason to use anything more than a 256-bit symmetric key. I gave the same advice in 2003 Practical Cryptography (pp. 65-6). Even a mythical quantum computer won’t be able to brute-force that large a keyspace. (Public keys are different, of course—see Table 2.2 of this NIST document for recommendations).

Of course, in the real world there are smarter ways than to brute-force keysearch. And the whole point of cipher cryptanalysis is to find shortcuts to brute-force search (like this attack on AES), but a 49,152-bit key is just plain stupid.

EDITED TO ADD (9/30): Now this is funny:

Some months ago I sent individual emails to each of seventeen experts in cryptology, all with the title of Doctor or Professor. My email was a first announcement to the academic world of the TOUAREG Encryption Algorithm, which, somewhat unusually, has a session key strength of over 49,000 bits and yet runs at 3 Megabytes per second. Bearing in mind that the strongest version of BLOWFISH has a session key of 448 bits and that every additional bit doubles the task of key-crashing, I imagined that my announcement would create more than a mild flutter of interest.

Much to his surprise, no one responded.

Here’s some more advice: my 1998 essay, “Memo to the Amateur Cipher Designer.” Anyone can design a cipher that he himself cannot break. It’s not even hard. So when you tell a cryptographer that you’ve designed a cipher that you can’t break, his first question will be “who the hell are you?” In other words, why should the fact that you can’t break a cipher be considered evidence of the cipher’s security?

If you want to design algorithms, start by breaking the ones out there. Practice by breaking algorithms that have already been broken (without peeking at the answers). Break something no one else has broken. Break another. Get your breaks published. When you have established yourself as someone who can break algorithms, then you can start designing new algorithms. Before then, no one will take you seriously.

EDITED TO ADD (9/30): I just did the math. An encryption speed of 8 megabytes per second on a 3.33 GHz CPU translates to about 400 clock cycles per byte. This is much, much slower than any of the AES finalists ten years ago, or any of the SHA-3 second round candidates today. It’s kind of embarrassingly slow, really.

Posted on September 30, 2009 at 5:52 AM • View Comments

iPhone Encryption Useless

Interesting, although I want some more technical details.

…the new iPhone 3GS’ encryption feature is “broken” when it comes to protecting sensitive information such as credit card numbers and social-security digits, Zdziarski said.

Zdziarski said it’s just as easy to access a user’s private information on an iPhone 3GS as it was on the previous generation iPhone 3G or first generation iPhone, both of which didn’t feature encryption. If a thief got his hands on an iPhone, a little bit of free software is all that’s needed to tap into all of the user’s content. Live data can be extracted in as little as two minutes, and an entire raw disk image can be made in about 45 minutes, Zdziarski said.

Wondering where the encryption comes into play? It doesn’t. Strangely, once one begins extracting data from an iPhone 3GS, the iPhone begins to decrypt the data on its own, he said.

Posted on July 29, 2009 at 6:16 AM • View Comments

Laptop Security while Crossing Borders

Last year, I wrote about the increasing propensity for governments, including the U.S. and Great Britain, to search the contents of people’s laptops at customs. What we know is still based on anecdote, as no country has clarified the rules about what their customs officers are and are not allowed to do, and what rights people have.

Companies and individuals have dealt with this problem in several ways, from keeping sensitive data off laptops traveling internationally, to storing the data—encrypted, of course—on websites and then downloading it at the destination. I have never liked either solution. I do a lot of work on the road, and need to carry all sorts of data with me all the time. It’s a lot of data, and downloading it can take a long time. Also, I like to work on long international flights.

There’s another solution, one that works with whole-disk encryption products like PGP Disk (I’m on PGP’s advisory board), TrueCrypt, and BitLocker: Encrypt the data to a key you don’t know.

It sounds crazy, but stay with me. Caveat: Don’t try this at home if you’re not very familiar with whatever encryption product you’re using. Failure results in a bricked computer. Don’t blame me.

Step One: Before you board your plane, add another key to your whole-disk encryption (it’ll probably mean adding another “user”)—and make it random. By “random,” I mean really random: Pound the keyboard for a while, like a monkey trying to write Shakespeare. Don’t make it memorable. Don’t even try to memorize it.

Technically, this key doesn’t directly encrypt your hard drive. Instead, it encrypts the key that is used to encrypt your hard drive—that’s how the software allows multiple users.

So now there are two different users named with two different keys: the one you normally use, and some random one you just invented.

Step Two: Send that new random key to someone you trust. Make sure the trusted recipient has it, and make sure it works. You won’t be able to recover your hard drive without it.

Step Three: Burn, shred, delete or otherwise destroy all copies of that new random key. Forget it. If it was sufficiently random and non-memorable, this should be easy.

Step Four: Board your plane normally and use your computer for the whole flight.

Step Five: Before you land, delete the key you normally use.

At this point, you will not be able to boot your computer. The only key remaining is the one you forgot in Step Three. There’s no need to lie to the customs official; you can even show him a copy of this article if he doesn’t believe you.

Step Six: When you’re safely through customs, get that random key back from your confidant, boot your computer and re-add the key you normally use to access your hard drive.

And that’s it.

This is by no means a magic get-through-customs-easily card. Your computer might be impounded, and you might be taken to court and compelled to reveal who has the random key.

But the purpose of this protocol isn’t to prevent all that; it’s just to deny any possible access to your computer to customs. You might be delayed. You might have your computer seized. (This will cost you any work you did on the flight, but—honestly—at that point that’s the least of your troubles.) You might be turned back or sent home. But when you’re back home, you have access to your corporate management, your personal attorneys, your wits after a good night’s sleep, and all the rights you normally have in whatever country you’re now in.

This procedure not only protects you against the warrantless search of your data at the border, it also allows you to deny a customs official your data without having to lie or pretend—which itself is often a crime.

Now the big question: Who should you send that random key to?

Certainly it should be someone you trust, but—more importantly—it should be someone with whom you have a privileged relationship. Depending on the laws in your country, this could be your spouse, your attorney, your business partner or your priest. In a larger company, the IT department could institutionalize this as a policy, with the help desk acting as the key holder.

You could also send it to yourself, but be careful. You don’t want to e-mail it to your webmail account, because then you’d be lying when you tell the customs official that there is no possible way you can decrypt the drive.

You could put the key on a USB drive and send it to your destination, but there are potential failure modes. It could fail to get there in time to be waiting for your arrival, or it might not get there at all. You could airmail the drive with the key on it to yourself a couple of times, in a couple of different ways, and also fax the key to yourself … but that’s more work than I want to do when I’m traveling.

If you only care about the return trip, you can set it up before you return. Or you can set up an elaborate one-time pad system, with identical lists of keys with you and at home: Destroy each key on the list you have with you as you use it.

Remember that you’ll need to have full-disk encryption, using a product such as PGP Disk, TrueCrypt or BitLocker, already installed and enabled to make this work.

I don’t think we’ll ever get to the point where our computer data is safe when crossing an international border. Even if countries like the U.S. and Britain clarify their rules and institute privacy protections, there will always be other countries that will exercise greater latitude with their authority. And sometimes protecting your data means protecting your data from yourself.

This essay originally appeared on Wired.com.

Posted on July 15, 2009 at 12:10 PM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.