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Post-quantum cryptography is now one pip-install away for the entire Python ecosystem. With funding from the Sovereign Tech Agency, we implemented support for ML-KEM, the NIST-standard key-establishment primitive, and ML-DSA, the NIST-standard digital-signature primitive, in pyca/cryptography.
Remember, the reason to do this now is because there’s no emergency. And because you will make your systems crypto agile, which is always a good idea.
New paper: “Encryption and Globalization 15 Years Later: End-to-End Encryption and the Third Round of the ‘Going Dark’ Debate“:
Abstract: This Article updates and expands on 2012 research on encryption and globalization, analyzing what the authors call “Round 3” of the Going Dark Debate: the current controversies over end-to-end encryption (E2EE). Governments around the world have proposed, and in some cases enacted, laws limiting E2EE for law enforcement and national security purposes.
This Article explains the underlying technologies and market developments for a law and policy audience to assess those proposals critically. The Article proceeds in three parts tracking three rounds of the Going Dark Debate. Round 1 covers the Crypto Wars of the 1990s, when U.S. export controls on strong encryption ultimately fell in 1999. Round 2 covers the period roughly 2010 to 2015, when encryption-in-transit became widespread but lawful access remained available through cloud providers, giving rise to what the authors called a “golden age of surveillance” rather than a period of going dark. Round 3 addresses the current debate over E2EE, where no entity between sender and recipient can read the plaintext.
The Article’s first major contribution is identifying five technically distinct scenarios for how E2EE operates in practice, each with different implications for lawful access. These scenarios reveal a substantial gap between the assumption that E2EE categorically blocks lawful access and the reality of how communications are sent and received. Second, the Article shows that E2EE is not limited to messaging; instead, it is embedded throughout the modern technology stack, including in Transport Layer Security, Secure Shell, Virtual Private Networks, and Zero Trust Architecture, the last of which is now legally required under U.S. and EU law. Any law broadly limiting E2EE would thus have severe serious consequences for cybersecurity, commerce, and government operations. The Article concludes that the two key lessons from Round 2—the least trusted country problem and the golden age of surveillance—remain true in Round 3, and that new government claims for restricting effective encryption deserve great skepticism.
Really interesting piece of cryptographic history:
In November 2023, a large cache of his wartime papers—nicknamed the “Bayley papers”—was auctioned in London for almost half a million U.S. dollars. The previously unknown cache contains many sheets in Turing’s own handwriting, telling of his top-secret “Delilah” engineering project from 1943 to 1945. Delilah was Turing’s portable voice-encryption system, named after the biblical deceiver of men. There is also material written by Bayley, often in the form of notes he took while Turing was speaking. It is thanks to Bayley that the papers survived: He kept them until he died in 2020, 66 years after Turing passed away.
France is accelerating its transition to post-quantum encryption:
France’s cybersecurity agency ANSSI said on Tuesday it would stop certifying security products that lack quantum-resistant encryption, a move that will force government bodies and critical operators to shift away from older systems.
Samih Souissi, ANSSI’s chief of staff, said at the France Quantum conference that the agency would halt such certifications from 2027, and that businesses should be buying only quantum-safe products by 2030.
ANSSI approval is required for use in French government agencies and critical infrastructure, making the policy a de facto phase-out of older encryption.
Interesting research on a new class of weak RSA keys: keys with lots of zeros. It turns out that these keys are out in the wild.
The badkeys project is an open-source service that checks public keys for known vulnerabilities. While developing this tool, Hanno collected a massive number of real-world keys from public sources, including Certificate Transparency logs, internet-wide TLS and SSH scans, PGP keys, and many others. By searching this dataset for unexpectedly sparse RSA moduli, we uncovered a large number of keys in the wild with the patterns in Figure 1.
Both patterns include several regularly spaced blocks of all zeros interleaved with seemingly random data. Pattern 1 appears in CT logs for certificates issued to several large organizations, including Yahoo and Verizon, and on some devices running NetApp software. Fortunately, these certificates have already expired, but we still shared our findings with these companies. We wanted to learn more about which product could be responsible for generating these keys, but we did not hear back. Pattern 2 appears on SSH hosts running the CompleteFTP software from EnterpriseDT. The underlying vulnerability affects RSA keys generated using versions 10.0.012.0.0 (Dec 2016Mar 2019) and DSA keys generated with v10.0.023.0.4 (Dec 2016Dec 2023).
These vulnerabilities affect a small minority of hosts on the internet, but the more interesting takeaway is that independent cryptographic implementations failed in similar ways. More implementations may include the same bugs, and so it’s worth tailoring cryptanalytic algorithms for this particular type of failure.
The article doesn’t speculate, but I will. This could be a deliberately designed backdoor, of the sort I wrote about back in 2013. I could imagine some government agency figuring out how to break this class of RSA keys, and then convincing different providers to hand them out to users.
According to a new law, the Hong Kong police can demand that you reveal the encryption keys protecting your computer, phone, hard drives, etc.—even if you are just transiting the airport.
In a security alert dated March 26, the U.S. Consulate General said that, on March 23, 2026, Hong Kong authorities changed the rules governing enforcement of the National Security Law. Under the revised framework, police can require individuals to provide passwords or other assistance to access personal electronic devices, including cellphones and laptops.
The consulate warned that refusal to comply is now a criminal offense. It also said authorities have expanded powers to take and keep personal electronic devices as evidence if they claim the devices are linked to national security offenses.
Mike Masnick points out that the recent New Mexico court ruling against Meta has some bad implications for end-to-end encryption, and security in general:
If the “design choices create liability” framework seems worrying in the abstract, the New Mexico case provides a concrete example of where it leads in practice.
One of the key pieces of evidence the New Mexico attorney general used against Meta was the company’s 2023 decision to add end-to-end encryption to Facebook Messenger. The argument went like this: predators used Messenger to groom minors and exchange child sexual abuse material. By encrypting those messages, Meta made it harder for law enforcement to access evidence of those crimes. Therefore, the encryption was a design choice that enabled harm.
The state is now seeking court-mandated changes including “protecting minors from encrypted communications that shield bad actors.”
Yes, the end result of the New Mexico ruling might be that Meta is ordered to make everyone’s communications less secure. That should be terrifying to everyone. Even those cheering on the verdict.
End-to-end encryption protects billions of people from surveillance, data breaches, authoritarian governments, stalkers, and domestic abusers. It’s one of the most important privacy and security tools ordinary people have. Every major security expert and civil liberties organization in the world has argued for stronger encryption, not weaker.
But under the “design liability” theory, implementing encryption becomes evidence of negligence, because a small number of bad actors also use encrypted communications. The logic applies to literally every communication tool ever invented. Predators also use the postal service, telephones, and in-person conversation. The encryption itself harms no one. Like infinite scroll and autoplay, it is inert without the choices of bad actors - choices made by people, not by the platform’s design.
The incentive this creates goes far beyond encryption, and it’s bad. If any product improvement that protects the majority of users can be held against you because a tiny fraction of bad actors exploit it, companies will simply stop making those improvements. Why add encryption if it becomes Exhibit A in a future lawsuit? Why implement any privacy-protective feature if a plaintiff’s lawyer will characterize it as “shielding bad actors”?
And it gets worse. Some of the most damaging evidence in both trials came from internal company documents where employees raised concerns about safety risks and discussed tradeoffs. These were played up in the media (and the courtroom) as “smoking guns.” But that means no company is going to allow anyone to raise concerns ever again. That’s very, very bad.
In a sane legal environment, you want companies to have these internal debates. You want engineers and safety teams to flag potential risks, wrestle with difficult tradeoffs, and document their reasoning. But when those good-faith deliberations become plaintiff’s exhibits presented to a jury as proof that “they knew and did it anyway,” the rational corporate response is to stop putting anything in writing. Stop doing risk assessments. Stop asking hard questions internally.
The lesson every general counsel in Silicon Valley is learning right now: ignorance is safer than inquiry. That makes everyone less safe, not more.
The essay has a lot more: about Section 230, about competition in this space, about the myopic nature of the ruling. Go read it.
After twenty-six years, Microsoft is finally upgrading the last remaining instance of the encryption algorithm RC4 in Windows.
One of the most visible holdouts in supporting RC4 has been Microsoft. Eventually, Microsoft upgraded Active Directory to support the much more secure AES encryption standard. But by default, Windows servers have continued to respond to RC4-based authentication requests and return an RC4-based response. The RC4 fallback has been a favorite weakness hackers have exploited to compromise enterprise networks. Use of RC4 played a key role in last year’s breach of health giant Ascension. The breach caused life-threatening disruptions at 140 hospitals and put the medical records of 5.6 million patients into the hands of the attackers. US Senator Ron Wyden (D-Ore.) in September called on the Federal Trade Commission to investigate Microsoft for “gross cybersecurity negligence,” citing the continued default support for RC4.
Last week, Microsoft said it was finally deprecating RC4 and cited its susceptibility to Kerberoasting, the form of attack, known since 2014, that was the root cause of the initial intrusion into Ascension’s network.
Fun fact: RC4 was a trade secret until I published the algorithm in the second edition of Applied Cryptography in 1995.
Here’s a fun paper: “The Naibbe cipher: a substitution cipher that encrypts Latin and Italian as Voynich Manuscript-like ciphertext“:
Abstract: In this article, I investigate the hypothesis that the Voynich Manuscript (MS 408, Yale University Beinecke Library) is compatible with being a ciphertext by attempting to develop a historically plausible cipher that can replicate the manuscript’s unusual properties. The resulting ciphera verbose homophonic substitution cipher I call the Naibbe ciphercan be done entirely by hand with 15th-century materials, and when it encrypts a wide range of Latin and Italian plaintexts, the resulting ciphertexts remain fully decipherable and also reliably reproduce many key statistical properties of the Voynich Manuscript at once. My results suggest that the so-called “ciphertext hypothesis” for the Voynich Manuscript remains viable, while also placing constraints on plausible substitution cipher structures.
A new anonymous phone service allows you to sign up with just a zip code.
Sidebar photo of Bruce Schneier by Joe MacInnis.