Entries Tagged "encryption"

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European Court of Human Rights Rejects Encryption Backdoors

The European Court of Human Rights has ruled that breaking end-to-end encryption by adding backdoors violates human rights:

Seemingly most critically, the [Russian] government told the ECHR that any intrusion on private lives resulting from decrypting messages was “necessary” to combat terrorism in a democratic society. To back up this claim, the government pointed to a 2017 terrorist attack that was “coordinated from abroad through secret chats via Telegram.” The government claimed that a second terrorist attack that year was prevented after the government discovered it was being coordinated through Telegram chats.

However, privacy advocates backed up Telegram’s claims that the messaging services couldn’t technically build a backdoor for governments without impacting all its users. They also argued that the threat of mass surveillance could be enough to infringe on human rights. The European Information Society Institute (EISI) and Privacy International told the ECHR that even if governments never used required disclosures to mass surveil citizens, it could have a chilling effect on users’ speech or prompt service providers to issue radical software updates weakening encryption for all users.

In the end, the ECHR concluded that the Telegram user’s rights had been violated, partly due to privacy advocates and international reports that corroborated Telegram’s position that complying with the FSB’s disclosure order would force changes impacting all its users.

The “confidentiality of communications is an essential element of the right to respect for private life and correspondence,” the ECHR’s ruling said. Thus, requiring messages to be decrypted by law enforcement “cannot be regarded as necessary in a democratic society.”

Posted on February 19, 2024 at 11:15 AM • View Comments

Signal Will Leave the UK Rather Than Add a Backdoor

Totally expected, but still good to hear:

Onstage at TechCrunch Disrupt 2023, Meredith Whittaker, the president of the Signal Foundation, which maintains the nonprofit Signal messaging app, reaffirmed that Signal would leave the U.K. if the country’s recently passed Online Safety Bill forced Signal to build “backdoors” into its end-to-end encryption.

“We would leave the U.K. or any jurisdiction if it came down to the choice between backdooring our encryption and betraying the people who count on us for privacy, or leaving,” Whittaker said. “And that’s never not true.”

Posted on September 26, 2023 at 7:15 AM • View Comments

You Can’t Rush Post-Quantum-Computing Cryptography Standards

I just read an article complaining that NIST is taking too long in finalizing its post-quantum-computing cryptography standards.

This process has been going on since 2016, and since that time there has been a huge increase in quantum technology and an equally large increase in quantum understanding and interest. Yet seven years later, we have only four algorithms, although last week NIST announced that a number of other candidates are under consideration, a process that is expected to take “several years.

The delay in developing quantum-resistant algorithms is especially troubling given the time it will take to get those products to market. It generally takes four to six years with a new standard for a vendor to develop an ASIC to implement the standard, and it then takes time for the vendor to get the product validated, which seems to be taking a troubling amount of time.

Yes, the process will take several years, and you really don’t want to rush it. I wrote this last year:

Ian Cassels, British mathematician and World War II cryptanalyst, once said that “cryptography is a mixture of mathematics and muddle, and without the muddle the mathematics can be used against you.” This mixture is particularly difficult to achieve with public-key algorithms, which rely on the mathematics for their security in a way that symmetric algorithms do not. We got lucky with RSA and related algorithms: their mathematics hinge on the problem of factoring, which turned out to be robustly difficult. Post-quantum algorithms rely on other mathematical disciplines and problems­—code-based cryptography, hash-based cryptography, lattice-based cryptography, multivariate cryptography, and so on­—whose mathematics are both more complicated and less well-understood. We’re seeing these breaks because those core mathematical problems aren’t nearly as well-studied as factoring is.

[…]

As the new cryptanalytic results demonstrate, we’re still learning a lot about how to turn hard mathematical problems into public-key cryptosystems. We have too much math and an inability to add more muddle, and that results in algorithms that are vulnerable to advances in mathematics. More cryptanalytic results are coming, and more algorithms are going to be broken.

As to the long time it takes to get new encryption products to market, work on shortening it:

The moral is the need for cryptographic agility. It’s not enough to implement a single standard; it’s vital that our systems be able to easily swap in new algorithms when required.

Whatever NIST comes up with, expect that it will get broken sooner than we all want. It’s the nature of these trap-door functions we’re using for public-key cryptography.

Posted on August 8, 2023 at 7:13 AM • View Comments

Backdoor in TETRA Police Radios

Seems that there is a deliberate backdoor in the twenty-year-old TErrestrial Trunked RAdio (TETRA) standard used by police forces around the world.

The European Telecommunications Standards Institute (ETSI), an organization that standardizes technologies across the industry, first created TETRA in 1995. Since then, TETRA has been used in products, including radios, sold by Motorola, Airbus, and more. Crucially, TETRA is not open-source. Instead, it relies on what the researchers describe in their presentation slides as “secret, proprietary cryptography,” meaning it is typically difficult for outside experts to verify how secure the standard really is.

The researchers said they worked around this limitation by purchasing a TETRA-powered radio from eBay. In order to then access the cryptographic component of the radio itself, Wetzels said the team found a vulnerability in an interface of the radio.

[…]

Most interestingly is the researchers’ findings of what they describe as the backdoor in TEA1. Ordinarily, radios using TEA1 used a key of 80-bits. But Wetzels said the team found a “secret reduction step” which dramatically lowers the amount of entropy the initial key offered. An attacker who followed this step would then be able to decrypt intercepted traffic with consumer-level hardware and a cheap software defined radio dongle.

Looks like the encryption algorithm was intentionally weakened by intelligence agencies to facilitate easy eavesdropping.

Specifically on the researchers’ claims of a backdoor in TEA1, Boyer added “At this time, we would like to point out that the research findings do not relate to any backdoors. The TETRA security standards have been specified together with national security agencies and are designed for and subject to export control regulations which determine the strength of the encryption.”

And I would like to point out that that’s the very definition of a backdoor.

Why aren’t we done with secret, proprietary cryptography? It’s just not a good idea.

Details of the security analysis. Another news article.

Posted on July 26, 2023 at 7:05 AM • View Comments

AI-Generated Steganography

New research suggests that AIs can produce perfectly secure steganographic images:

Abstract: Steganography is the practice of encoding secret information into innocuous content in such a manner that an adversarial third party would not realize that there is hidden meaning. While this problem has classically been studied in security literature, recent advances in generative models have led to a shared interest among security and machine learning researchers in developing scalable steganography techniques. In this work, we show that a steganography procedure is perfectly secure under Cachin (1998)’s information theoretic-model of steganography if and only if it is induced by a coupling. Furthermore, we show that, among perfectly secure procedures, a procedure is maximally efficient if and only if it is induced by a minimum entropy coupling. These insights yield what are, to the best of our knowledge, the first steganography algorithms to achieve perfect security guarantees with non-trivial efficiency; additionally, these algorithms are highly scalable. To provide empirical validation, we compare a minimum entropy coupling-based approach to three modern baselines—arithmetic coding, Meteor, and adaptive dynamic grouping—using GPT-2, WaveRNN, and Image Transformer as communication channels. We find that the minimum entropy coupling-based approach achieves superior encoding efficiency, despite its stronger security constraints. In aggregate, these results suggest that it may be natural to view information-theoretic steganography through the lens of minimum entropy coupling.

News article.

EDITED TO ADD (6/13): Comments.

Posted on June 12, 2023 at 7:18 AM • View Comments

UK Threatens End-to-End Encryption

In an open letter, seven secure messaging apps—including Signal and WhatsApp—point out that the UK’s Online Safety Bill could destroy end-to-end encryption:

As currently drafted, the Bill could break end-to-end encryption,opening the door to routine, general and indiscriminate surveillance of personal messages of friends, family members, employees, executives, journalists, human rights activists and even politicians themselves, which would fundamentally undermine everyone’s ability to communicate securely.

The Bill provides no explicit protection for encryption, and if implemented as written, could empower OFCOM to try to force the proactive scanning of private messages on end-to-end encrypted communication services—nullifying the purpose of end-to-end encryption as a result and compromising the privacy of all users.

In short, the Bill poses an unprecedented threat to the privacy, safety and security of every UK citizen and the people with whom they communicate around the world, while emboldening hostile governments who may seek to draft copy-cat laws.

Both Signal and WhatsApp have said that they will cease services in the UK rather than compromise the security of their users worldwide.

Posted on April 24, 2023 at 6:39 AM • View Comments

Side-Channel Attack against CRYSTALS-Kyber

CRYSTALS-Kyber is one of the public-key algorithms currently recommended by NIST as part of its post-quantum cryptography standardization process.

Researchers have just published a side-channel attack—using power consumption—against an implementation of the algorithm that was supposed to be resistant against that sort of attack.

The algorithm is not “broken” or “cracked”—despite headlines to the contrary—this is just a side-channel attack. What makes this work really interesting is that the researchers used a machine-learning model to train the system to exploit the side channel.

Posted on February 28, 2023 at 7:19 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.