Entries Tagged "encryption"

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Why Is the NSA Moving Away from Elliptic Curve Cryptography?

In August, I wrote about the NSA’s plans to move to quantum-resistant algorithms for its own cryptographic needs.

Cryptographers Neal Koblitz and Alfred Menezes just published a long paper speculating as to the government’s real motives for doing this. They range from some new cryptanalysis of ECC to a political need after the DUAL_EC_PRNG disaster—to the stated reason of quantum computing fears.

Read the whole paper. (Feel free to skip over the math if it gets too hard, but keep going until the end.)

EDITED TO ADD (11/15): A commentary and critique of the paper by Matthew Green.

Posted on October 28, 2015 at 2:11 PMView Comments

Breaking Diffie-Hellman with Massive Precomputation (Again)

The Internet is abuzz with this blog post and paper, speculating that the NSA is breaking the Diffie-Hellman key-exchange protocol in the wild through massive precomputation.

I wrote about this at length in May when this paper was first made public. (The reason it’s news again is that the paper was just presented at the ACM Computer and Communications Security conference.)

What’s newly being talked about his how this works inside the NSA surveillance architecture. Nicholas Weaver explains:

To decrypt IPsec, a large number of wiretaps monitor for IKE (Internet Key Exchange) handshakes, the protocol that sets up a new IPsec encrypted connection. The handshakes are forwarded to a decryption oracle, a black box system that performs the magic. While this happens, the wiretaps also record all traffic in the associated IPsec connections.

After a period of time, this oracle either returns the private keys or says “i give up”. If the oracle provides the keys, the wiretap decrypts all the stored traffic and continues to decrypt the connection going forward.

[…]

This would also better match the security implications: just the fact that the NSA can decrypt a particular flow is a critical secret. Forwarding a small number of potentially-crackable flows to a central point better matches what is needed to maintain such secrecy.

Thus by performing the decryption in bulk at the wiretaps, complete with hardware acceleration to keep up with the number of encrypted streams, this architecture directly implies that the NSA can break a massive amount of IPsec traffic, a degree of success which implies a cryptanalysis breakthrough.

That last paragraph is Weaver explaining how this attack matches the NSA rhetoric about capabilities in some of their secret documents.

Now that this is out, I’m sure there are a lot of really upset people inside the NSA.

EDITED TO ADD (11/15): How to protect yourself.

Posted on October 16, 2015 at 6:19 AMView Comments

Obama Administration Not Pursuing a Backdoor to Commercial Encryption

The Obama Administration is not pursuing a law that would force computer and communications manufacturers to add backdoors to their products for law enforcement. Sensibly, they concluded that criminals, terrorists, and foreign spies would use that backdoor as well.

Score one for the pro-security side in the Second Crypto War.

It’s certainly not over. The FBI hasn’t given up on an encryption backdoor (or other backdoor access to plaintext) since the early 1990s, and it’s not going to give up now. I expect there will be more pressure on companies, both overt and covert, more insinuations that strong security is somehow responsible for crime and terrorism, and more behind-closed-doors negotiations.

Posted on October 14, 2015 at 9:39 AMView Comments

Self-Destructing Computer Chip

The chip is built on glass:

Shattering the glass is straightforward. When the proper circuit is toggled, a small resistor within the substrate heats up until the glass shatters. According to Corning, it will continue shattering even after the initial break, rendering the entire chip unusable. The demo chip resistor was triggered by a photo diode that switched the circuit when a laser shone upon it. The glass plate quickly shattered into fragments once the laser touches it.

Posted on September 17, 2015 at 7:17 AMView Comments

Wanted: Cryptography Products for Worldwide Survey

In 1999, Lance Hoffman, David Balenson, and others published a survey of non-US cryptographic products. The point of the survey was to illustrate that there was a robust international market in these products, and that US-only export restrictions on strong encryption did nothing to prevent its adoption and everything to disadvantage US corporations. This was an important contribution during the First Crypto War, and Hoffman testified before a Senate committee on his findings.

I want to redo that survey for 2015.

Here, at the beginning of the Second Crypto War, we again need to understand which encryption products are outside the reach of US regulation (or UK regulation). Are there so many foreign crypto products that any regulation by only one country will be easily circumvented? Or has the industry consolidated around only a few products made by only a few countries, so that effective regulation of strong encryption is possible? What are the possibilities for encrypted communication and data storage? I honestly don’t know the answer—and I think it’s important to find out.

To that end, I am asking for help. Please respond in the comments with the names—and URLs—of non-US encryption software and hardware products. I am only interested in those useful for protecting communications and data storage. I don’t care about encrypting financial transactions, or anything of that sort.

Thank you for your help. And please forward this blog post to anyone else who might help.

EDITED TO ADD: Thinking about it more, I want to compile a list of domestic (U.S.) encryption products as well. Since right now the FBI seems intent on just pressuring the big companies like Apple and Microsoft, and not regulating cryptography in general, knowing what else is out there in the U.S. will be useful.

Posted on September 11, 2015 at 2:08 PMView Comments

NSA Plans for a Post-Quantum World

Quantum computing is a novel way to build computers—one that takes advantage of the quantum properties of particles to perform operations on data in a very different way than traditional computers. In some cases, the algorithm speedups are extraordinary.

Specifically, a quantum computer using something called Shor’s algorithm can efficiently factor numbers, breaking RSA. A variant can break Diffie-Hellman and other discrete log-based cryptosystems, including those that use elliptic curves. This could potentially render all modern public-key algorithms insecure. Before you panic, note that the largest number to date that has been factored by a quantum computer is 143. So while a practical quantum computer is still science fiction, it’s not stupid science fiction.

(Note that this is completely different from quantum cryptography, which is a way of passing bits between two parties that relies on physical quantum properties for security. The only thing quantum computation and quantum cryptography have to do with each other is their first words. It is also completely different from the NSA’s QUANTUM program, which is its code name for a packet-injection system that works directly in the Internet backbone.)

Practical quantum computation doesn’t mean the end of cryptography. There are lesser-known public-key algorithms such as McEliece and lattice-based algorithms that, while less efficient than the ones we use, are currently secure against a quantum computer. And quantum computation only speeds up a brute-force keysearch by a factor of a square root, so any symmetric algorithm can be made secure against a quantum computer by doubling the key length.

We know from the Snowden documents that the NSA is conducting research on both quantum computation and quantum cryptography. It’s not a lot of money, and few believe that the NSA has made any real advances in theoretical or applied physics in this area. My guess has been that we’ll see a practical quantum computer within 30 to 40 years, but not much sooner than that.

This all means that now is the time to think about what living in a post-quantum world would be like. NIST is doing its part, having hosted a conference on the topic earlier this year. And the NSA announced that it is moving towards quantum-resistant algorithms.

Earlier this week, the NSA’s Information Assurance Directorate updated its list of Suite B cryptographic algorithms. It explicitly talked about the threat of quantum computers:

IAD will initiate a transition to quantum resistant algorithms in the not too distant future. Based on experience in deploying Suite B, we have determined to start planning and communicating early about the upcoming transition to quantum resistant algorithms. Our ultimate goal is to provide cost effective security against a potential quantum computer. We are working with partners across the USG, vendors, and standards bodies to ensure there is a clear plan for getting a new suite of algorithms that are developed in an open and transparent manner that will form the foundation of our next Suite of cryptographic algorithms.

Until this new suite is developed and products are available implementing the quantum resistant suite, we will rely on current algorithms. For those partners and vendors that have not yet made the transition to Suite B elliptic curve algorithms, we recommend not making a significant expenditure to do so at this point but instead to prepare for the upcoming quantum resistant algorithm transition.

Suite B is a family of cryptographic algorithms approved by the NSA. It’s all part of the NSA’s Cryptographic Modernization Program. Traditionally, NSA algorithms were classified and could only be used in specially built hardware modules. Suite B algorithms are public, and can be used in anything. This is not to say that Suite B algorithms are second class, or breakable by the NSA. They’re being used to protect US secrets: “Suite A will be used in applications where Suite B may not be appropriate. Both Suite A and Suite B can be used to protect foreign releasable information, US-Only information, and Sensitive Compartmented Information (SCI).”

The NSA is worried enough about advances in the technology to start transitioning away from algorithms that are vulnerable to a quantum computer. Does this mean that the agency is close to a working prototype in their own classified labs? Unlikely. Does this mean that they envision practical quantum computers sooner than my 30-to-40-year estimate? Certainly.

Unlike most personal and corporate applications, the NSA routinely deals with information it wants kept secret for decades. Even so, we should all follow the NSA’s lead and transition our own systems to quantum-resistant algorithms over the next decade or so—possibly even sooner.

The essay previously appeared on Lawfare.

EDITED TO ADD: The computation that factored 143 also accidentally “factored much larger numbers such as 3599, 11663, and 56153, without the awareness of the authors of that work,” which shows how weird this all is.

EDITED TO ADD: Seems that I need to be clearer: I do not stand by my 30-40-year prediction. The NSA is acting like practical quantum computers will exist long before then, and I am deferring to their expertise.

Posted on August 21, 2015 at 12:36 PMView Comments

Another Salvo in the Second Crypto War (of Words)

Prosecutors from New York, London, Paris, and Madrid wrote an op-ed in yesterday’s New York Times in favor of backdoors in cell phone encryption. There are a number of flaws in their argument, ranging from how easy it is to get data off an encrypted phone to the dangers of designing a backdoor in the first place, but all of that has been said before. And since anecdote can be more persuasive than data, the op-ed started with one:

In June, a father of six was shot dead on a Monday afternoon in Evanston, Ill., a suburb 10 miles north of Chicago. The Evanston police believe that the victim, Ray C. Owens, had also been robbed. There were no witnesses to his killing, and no surveillance footage either.

With a killer on the loose and few leads at their disposal, investigators in Cook County, which includes Evanston, were encouraged when they found two smartphones alongside the body of the deceased: an iPhone 6 running on Apple’s iOS 8 operating system, and a Samsung Galaxy S6 Edge running on Google’s Android operating system. Both devices were passcode protected.

You can guess the rest. A judge issued a warrant, but neither Apple nor Google could unlock the phones. “The homicide remains unsolved. The killer remains at large.”

The Intercept researched the example, and it seems to be real. The phones belonged to the victim, and…

According to Commander Joseph Dugan of the Evanston Police Department, investigators were able to obtain records of the calls to and from the phones, but those records did not prove useful. By contrast, interviews with people who knew Owens suggested that he communicated mainly through text messages—the kind that travel as encrypted data—and had made plans to meet someone shortly before he was shot.

The information on his phone was not backed up automatically on Apple’s servers—apparently because he didn’t use wi-fi, which backups require.

[…]

But Dugan also wasn’t as quick to lay the blame solely on the encrypted phones. “I don’t know if getting in there, getting the information, would solve the case,” he said, “but it definitely would give us more investigative leads to follow up on.”

This is the first actual example I’ve seen illustrating the value of a backdoor. Unlike the increasingly common example of an ISIL handler abroad communicating securely with a radicalized person in the US, it’s an example where a backdoor might have helped. I say “might have,” because the Galaxy S6 is not encrypted by default, which means the victim deliberately turned the encryption on. If the native smartphone encryption had been backdoored, we don’t know if the victim would have turned it on nevertheless, or if he would have employed a different, non-backdoored, app.

The authors’ other examples are much sloppier:

Between October and June, 74 iPhones running the iOS 8 operating system could not be accessed by investigators for the Manhattan district attorney’s office—despite judicial warrants to search the devices. The investigations that were disrupted include the attempted murder of three individuals, the repeated sexual abuse of a child, a continuing sex trafficking ring and numerous assaults and robberies.

[…]

In France, smartphone data was vital to the swift investigation of the Charlie Hebdo terrorist attacks in January, and the deadly attack on a gas facility at Saint-Quentin-Fallavier, near Lyon, in June. And on a daily basis, our agencies rely on evidence lawfully retrieved from smartphones to fight sex crimes, child abuse, cybercrime, robberies or homicides.

We’ve heard that 74 number before. It’s over nine months, in an office that handles about 100,000 cases a year: less than 0.1% of the time. Details about those cases would be useful, so we can determine if encryption was just an impediment to investigation, or resulted in a criminal going free. The government needs to do a better job of presenting empirical data to support its case for backdoors. That they’re unable to do so suggests very strongly that an empirical analysis wouldn’t favor the government’s case.

As to the Charlie Hebdo case, it’s not clear how much of that vital smartphone data was actual data, and how much of it was unable-to-be-encrypted metadata. I am reminded of the examples that then-FBI-Director Louis Freeh would give during the First Crypto Wars in the 1990s. The big one used to illustrate the dangers of encryption was Mafia boss John Gotti. But the surveillance that convicted him was a room bug, not a wiretap. Given that the examples from FBI Director James Comey’s “going dark” speech last year were bogus, skepticism in the face of anecdote seems prudent.

So much of this “going dark” versus the “golden age of surveillance” debate depends on where you start from. Referring to that first Evanston example and the inability to get evidence from the victim’s phones, the op-ed authors write: “Until very recently, this situation would not have occurred.” That’s utter nonsense. From the beginning of time until very recently, this was the only situation that could have occurred. Objects in the vicinity of an event were largely mute about the past. Few things, save for eyewitnesses, could ever reach back in time and produce evidence. Even 15 years ago, the victim’s cell phone would have had no evidence on it that couldn’t have been obtained elsewhere, and that’s if the victim had been carrying a cell phone at all.

For most of human history, surveillance has been expensive. Over the last couple of decades, it has become incredibly cheap and almost ubiquitous. That a few bits and pieces are becoming expensive again isn’t a cause for alarm.

This essay originally appeared on Lawfare.

EDITED TO ADD (8/13): Excellent parody/commentary: “When Curtains Block Justice.”

Posted on August 12, 2015 at 2:18 PMView Comments

Nicholas Weaver on iPhone Security

Excellent essay:

Yes, an iPhone configured with a proper password has enough protection that, turned off, I’d be willing to hand mine over to the DGSE, NSA, or Chinese. But many (perhaps most) users don’t configure their phones right. Beyond just waiting for the suspect to unlock his phone, most people either use a weak 4-digit passcode (that can be brute-forced) or use the fingerprint reader (which the officer has a day to force the subject to use).

Furthermore, most iPhones have a lurking security landmine enabled by default: iCloud backup. A simple warrant to Apple can obtain this backup, which includes all photographs (so there is the selfie) and all undeleted iMessages! About the only information of value not included in this backup are the known WiFi networks and the suspect’s email, but a suspect’s email is a different warrant away anyway.

Finally, there is iMessage, whose “end-to-end” nature, despite FBI complaints, contains some significant weaknesses and deserves scare-quotes. To start with, iMessage’s encryption does not obscure any metadata, and as the saying goes, “the Metadata is the Message”. So with a warrant to Apple, the FBI can obtain all the information about every message sent and received except the message contents, including time, IP addresses, recipients, and the presence and size of attachments. Apple can’t hide this metadata, because Apple needs to use this metadata to deliver messages.

He explains how Apple could enable surveillance on iMessage and FaceTime:

So to tap Alice, it is straightforward to modify the keyserver to present an additional FBI key for Alice to everyone but Alice. Now the FBI (but not Apple) can decrypt all iMessages sent to Alice in the future. A similar modification, adding an FBI key to every request Alice makes for any keys other than her own, enables tapping all messages sent by Alice. There are similar architectural vulnerabilities which enable tapping of “end-to-end secure” FaceTime calls.

There’s a persistent rumor going around that Apple is in the secret FISA Court, fighting a government order to make its platform more surveillance-friendly—and they’re losing. This might explain Apple CEO Tim Cook’s somewhat sudden vehemence about privacy. I have not found any confirmation of the rumor.

Posted on August 6, 2015 at 6:09 AMView Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.