Entries Tagged "keys"

Page 7 of 13

Master Keys

Earlier this month, a retired New York City locksmith was selling a set of “master keys” on eBay:

Three of the five are standard issue for members of the FDNY, and the set had a metal dog tag that was embossed with an FDNY lieutenant’s shield number, 6896.

The keys include the all-purpose “1620,” a master firefighter key that with one turn could trap thousands of people in a skyscraper by sending all the elevators to the lobby and out of service, according to two FDNY sources. And it works for buildings across the city.

That key also allows one to open locked subway entrances, gain entry to many firehouses and get into boxes at construction jobs that house additional keys to all areas of the site.

The ring sold to The Post has two keys used by official city electricians that would allow access to street lamps, along with the basement circuit-breaker boxes of just about any large building.

Of course there’s the terrorist tie-in:

“With all the anti-terrorism activities, with all the protection that the NYPD is trying to provide, it’s astounding that you could get hold of this type of thing,” he said.

He walked The Post through a couple of nightmare scenarios that would be possible with the help of such keys.

“Think about the people at Occupy Wall Street who hate the NYPD, hate the establishment. They would love to have a set. Wouldn’t it be nice to walk in and disable Chase’s elevators?” he said.

Or, he said, “I could open the master box at construction sites, which hold the keys and the building plans. Once you get inside, you can steal, vandalize or conduct terrorist activities.”

The Huffington Post piled on:

“We cannot let anyone sell the safety of over 8 million people so easily,” New York City Public Advocate Bill de Blasio said in a statement. “Having these keys on the open market literally puts lives at risk. The billions we’ve spent on counter-terrorism have been severely undercut by this breech [sic].”

Sounds terrible. But — good news — the locksmith has stopped selling them. (On the other hand, the press has helpfully published a photograph of the keys, so you can make your own, even if you didn’t win the eBay auction.)

I found only one story that failed to hype the threat.

The current bit of sensationalism aside, this is fundamentally a hard problem. Master keys are only useful if they’re widely applicable — and if they’re widely applicable, they need to be distributed widely. This means that 1) they can’t be kept secret, and 2) they’re very expensive to update. I could easily imagine an electronic lock solution that would be much more adaptable, but electronic locks come with their own vulnerabilities, since the electronics are something else that can fail. I don’t know if a more complex system would be better in the end.

Posted on October 15, 2012 at 7:02 AMView Comments

Making Handcuff Keys with 3D Printers

Handcuffs pose a particular key management problem. Officers need to be able to unlock handcuffs locked by another officer, so they’re all designed to be opened by a standard set of keys. This system only works if the bad guys can’t get a copy of the key, and modern handcuff manufacturers go out of their way to make it hard for regular people to get copies of the key.

At the recent HOPE conference, someone made copies of these keys using a 3D printer:

In a workshop Friday at the Hackers On Planet Earth conference in New York, a German hacker and security consultant who goes by the name “Ray” demonstrated a looming problem for handcuff makers hoping to restrict the distribution of the keys that open their cuffs: With plastic copies he cheaply produced with a laser-cutter and a 3D printer, he was able to open handcuffs built by the German firm Bonowi and the English manufacturer Chubb, both of which attempt to control the distribution of their keys to keep them exclusively in the hands of authorized buyers such as law enforcement.


Unlike keys for more common handcuffs, which can be purchased (even in forms specifically designed to be concealable) from practically any survivalist or police surplus store, Bonowi’s and Chubb’s keys can’t be acquired from commercial vendors. Ray says he bought a Chubb key from eBay, where he says they intermittently appear, and obtained the rarer Bonowi key through a source he declined to name. Then he precisely measured them with calipers and created CAD models, which he used to reproduce the keys en masse, both in plexiglass with a friend’s standard laser cutter and in ABS plastic with a Repman 3D printer. Both types of tools can be found in hacker spaces around the U.S. and, in the case of 3D printers, thousands of consumers’ homes.

EDITED TO ADD (7/29): Interesting comment.

EDITED TO ADD (8/13): Comment from the presenter.

Posted on July 25, 2012 at 6:42 AMView Comments

Lousy Random Numbers Cause Insecure Public Keys

There’s some excellent research (paper, news articles) surveying public keys in the wild. Basically, the researchers found that a small fraction of them (27,000 out of 7.1 million, or 0.38%) share a common factor and are inherently weak. The researchers can break those public keys, and anyone who duplicates their research can as well.

The cause of this is almost certainly a lousy random number generator used to create those public keys in the first place. This shouldn’t come as a surprise. One of the hardest parts of cryptography is random number generation. It’s really easy to write a lousy random number generator, and it’s not at all obvious that it is lousy. Randomness is a non-functional requirement, and unless you specifically test for it — and know how to test for it — you’re going to think your cryptosystem is working just fine. (One of the reporters who called me about this story said that the researchers told him about a real-world random number generator that produced just seven different random numbers.) So it’s likely these weak keys are accidental.

It’s certainly possible, though, that some random number generators have been deliberately weakened. The obvious culprits are national intelligence services like the NSA. I have no evidence that this happened, but if I were in charge of weakening cryptosystems in the real world, the first thing I would target is random number generators. They’re easy to weaken, and it’s hard to detect that you’ve done anything. Much safer than tweaking the algorithms, which can be tested against known test vectors and alternate implementations. But again, I’m just speculating here.

What is the security risk? There’s some, but it’s hard to know how much. We can assume that the bad guys can replicate this experiment and find the weak keys. But they’re random, so it’s hard to know how to monetize this attack. Maybe the bad guys will get lucky and one of the weak keys will lead to some obvious way to steal money, or trade secrets, or national intelligence. Maybe.

And what happens now? My hope is that the researchers know which implementations of public-key systems are susceptible to these bad random numbers — they didn’t name names in the paper — and alerted them, and that those companies will fix their systems. (I recommend my own Fortuna, from Cryptography Engineering.) I hope that everyone who implements a home-grown random number generator will rip it out and put in something better. But I don’t hold out much hope. Bad random numbers have broken a lot of cryptosystems in the past, and will continue to do so in the future.

From the introduction to the paper:

In this paper we complement previous studies by concentrating on computational and randomness properties of actual public keys, issues that are usually taken for granted. Compared to the collection of certificates considered in [12], where shared RSA moduli are “not very frequent”, we found a much higher fraction of duplicates. More worrisome is that among the 4.7 million distinct 1024-bit RSA moduli that we had originally collected, more than 12500 have a single prime factor in common. That this happens may be crypto-folklore, but it was new to us, and it does not seem to be a disappearing trend: in our current collection of 7.1 million 1024-bit RSA moduli, almost 27000 are vulnerable and 2048-bit RSA moduli are affected as well. When exploited, it could act the expectation of security that the public key infrastructure is intended to achieve.

And the conclusion:

We checked the computational properties of millions of public keys that we collected on the web. The majority does not seem to suffer from obvious weaknesses and can be expected to provide the expected level of security. We found that on the order of 0.003% of public keys is incorrect, which does not seem to be unacceptable. We were surprised, however, by the extent to which public keys are shared among unrelated parties. For ElGamal and DSA sharing is rare, but for RSA the frequency of sharing may be a cause for concern. What surprised us most is that many thousands of 1024-bit RSA moduli, including thousands that are contained in still valid X.509 certificates, offer no security at all. This may indicate that proper seeding of random number generators is still a problematic issue….

EDITED TO ADD (3/14): The title of the paper, “Ron was wrong, Whit is right” refers to the fact that RSA is inherently less secure because it needs two large random primes. Discrete log based algorithms, like DSA and ElGamal, are less susceptible to this vulnerability because they only need one random prime.

Posted on February 16, 2012 at 6:51 AMView Comments

What Happens When the Court Demands You Decrypt a Document and You Forget the Key?

Last month, a U.S. court demanded that a defendent surrender the encryption key to a laptop so the police could examine it. Now it seems that she’s forgotten the key.

What happens now? It seems as if this excuse would always be available to someone who doesn’t want the police to decrypt her files. On the other hand, it might be hard to realistically forget a key. It’s less credible for someone to say “I have no idea what my password is,” and more likely to say something like “it was the word ‘telephone’ with a zero for the o and then some number following — four digits, with a six in it — and then a punctuation mark like a period.” And then a brute-force password search could be targeted. I suppose someone could say “it was a random alphanumeric password created by an automatic program; I really have no idea,” but I’m not sure a judge would believe it.

Posted on February 13, 2012 at 5:20 AMView Comments

Official Malware from the German Police

The Chaos Computer Club has disassembled and analyzed the Trojan used by the German police for legal intercept. In its default mode, it takes regular screenshots of the active window and sends it to the police. It encrypts data in AES Electronic Codebook mode with — are you ready? — a fixed key across all versions. There’s no authentication built in, so it’s easy to spoof. It sends data to a command-and-control server in the U.S., which is almost certainly against German law. There’s code to allow the controller to install additional software onto the target machine, but that’s not authenticated either, so it would be easy to fool the Trojan into installing anything.

Detailed analysis in German. F-Secure has announced it will treat the Trojan as malware. I hope all the other anti-virus companies will do the same.

EDITED TO ADD (10/12): Another story. And some good information on the malware. Germany’s Justice Minister is calling for an investigation.

Posted on October 13, 2011 at 6:03 AMView Comments

Unredacted U.S. Diplomatic WikiLeaks Cables Published

It looks as if the entire mass of U.S. diplomatic cables that WikiLeaks had is available online somewhere. How this came about is a good illustration of how security can go wrong in ways you don’t expect.

Near as I can tell, this is what happened:

  1. In order to send the Guardian the cables, WikiLeaks encrypted them and put them on its website at a hidden URL.
  2. WikiLeaks sent the Guardian the URL.
  3. WikiLeaks sent the Guardian the encryption key.
  4. The Guardian downloaded and decrypted the file.
  5. WikiLeaks removed the file from their server.
  6. Somehow, the encrypted file ends up on BitTorrent. Perhaps someone found the hidden URL, downloaded the file, and then uploaded it to BitTorrent. Perhaps it is the “insurance file.” I don’t know.
  7. The Guardian published a book about WikiLeaks. Thinking the decryption key had no value, it published the key in the book.
  8. A reader used the key from the book to decrypt the archive from BitTorrent, and published the decrypted version: all the U.S. diplomatic cables in unredacted form.

Memo to the Guardian: Publishing encryption keys is almost always a bad idea. Memo to WikiLeaks: Using the same key for the Guardian and for the insurance file — if that’s what you did — was a bad idea.

EDITED TO ADD (9/1): From pp 138-9 of WikiLeaks:

Assange wrote down on a scrap of paper: ACollectionOfHistorySince_1966_ToThe_PresentDay#. “That’s the password,” he said. “But you have to add one extra word when you type it in. You have to put in the word ‘Diplomatic’ before the word ‘History’. Can you remember that?”

I think we can all agree that that’s a secure encryption key.

EDITED TO ADD (9/1): WikiLeaks says that the Guardian file and the insurance file are not encrypted with the same key. Which brings us back to the question: how did the encrypted Guardian file get loose?

EDITED TO ADD (9/1): Spiegel has the detailed story.

Posted on September 1, 2011 at 12:56 PMView Comments

Duplicating Physical Keys from Photographs (Sneakey)

In this demonstration, researchers photographed keys from 200 feet away and then made working copies. From the paper:

The access control provided by a physical lock is based on the assumption that the information content of the corresponding key is private — that duplication should require either possession of the key or a priori knowledge of how it was cut. However, the ever-increasing capabilities and prevalence of digital imaging technologies present a fundamental challenge to this privacy assumption. Using modest imaging equipment and standard computer vision algorithms, we demonstrate the effectiveness of physical key teleduplication — extracting a key’s complete and precise bitting code at a distance via optical decoding and then cutting precise duplicates. We describe our prototype system, Sneakey, and evaluate its effectiveness, in both laboratory and real-world settings, using the most popular residential key types in the U.S.

The design of common keys actually makes this process easier. There are only ten possible positions for each pin, any single key uses only half of those positions, and the positions of adjacent pins are deliberately set far apart.

EDITED TO ADD (7/26): I seem to have written about this in 2009. Apologies.

Posted on July 26, 2011 at 1:28 PMView Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.