A new paper presents a polynomial-time quantum algorithm for solving certain hard lattice problems. This could be a big deal for post-quantum cryptographic algorithms, since many of them base their security on hard lattice problems. A few things to note. One, this paper has not yet been peer reviewed …

Last week I posted a short memorial of Ross Anderson. The Communications of the ACM asked me to expand it. Here’s the longer version. [...]

Last week, I posted a short memorial of Ross Anderson. The Communications of the ACM asked me to expand it. Here’s the longer version. EDITED TO ADD (4/11): Two weeks before he passed away, Ross gave an 80-minute interview where he told his life story. [...]

Ross Anderson unexpectedly passed away Thursday night in, I believe, his home in Cambridge. I can’t remember when I first met Ross. Of course it was before 2008, when we created the Security and Human Behavior workshop. It was well before 2001, when we created the Workshop on …

Apple announced PQ3, its post-quantum encryption standard based on the Kyber secure key-encapsulation protocol, one of the post-quantum algorithms selected by NIST in 2022. There’s a lot of detail in the Apple blog post, and more in Douglas Stabila’s security analysis. I am of two minds about …

The winner of the Best Paper Award at Crypto this year was a significant improvement to lattice-based cryptanalysis. This is important, because a bunch of NIST’s post-quantum options base their security on lattice problems. I worry about standardizing on post-quantum algorithms too quickly. We are still learning a …

David Kahn has died. His groundbreaking book, The Codebreakers was the first serious book I read about codebreaking, and one of the primary reasons I entered this field. He will be missed. [...]

We don’t have a useful quantum computer yet, but we do have quantum algorithms. Shor’s algorithm has the potential to factor large numbers faster than otherwise possible, which—if the run times are actually feasible—could break both the RSA and Diffie-Hellman public-key algorithms. Now, computer scientist …

Looks like fun. Details here. [...]

Adi Shamir et al. have a new model extraction attack on neural networks: Polynomial Time Cryptanalytic Extraction of Neural Network Models Abstract: Billions of dollars and countless GPU hours are currently spent on training Deep Neural Networks (DNNs) for a variety of tasks. Thus, it is essential to determine …

A group of Swiss researchers have published an impressive security analysis of Threema. We provide an extensive cryptographic analysis of Threema, a Swiss-based encrypted messaging application with more than 10 million users and 7000 corporate customers. We present seven different attacks against the protocol in three different threat models …

A group of Chinese researchers have just published a paper claiming that they can—although they have not yet done so—break 2048-bit RSA. This is something to take seriously. It might not be correct, but it’s not obviously wrong. We have long known from Shor’s algorithm …

Diplomatic code cracked after 500 years: In painstaking work backed by computers, Pierrot found “distinct families” of about 120 symbols used by Charles V. “Whole words are encrypted with a single symbol” and the emperor replaced vowels coming after consonants with marks, she said, an inspiration probably coming from …

Brian Krebs writes about how the Zeppelin ransomware encryption scheme was broken: The researchers said their break came when they understood that while Zeppelin used three different types of encryption keys to encrypt files, they could undo the whole scheme by factoring or computing just one of them: An …

Quantum computing is a completely new paradigm for computers. A quantum computer uses quantum properties such as superposition, which allows a qubit (a quantum bit) to be neither 0 nor 1, but something much more complicated. In theory, such a computer can solve problems too complex for conventional computers …

SIKE is one of the new algorithms that NIST recently added to the post-quantum cryptography competition. It was just broken, really badly. We present an efficient key recovery attack on the Supersingular Isogeny Diffie­-Hellman protocol (SIDH), based on a “glue-and-split” theorem due to Kani. Our attack exploits the …

Basically, the SafeZone library doesn’t sufficiently randomize the two prime numbers it used to generate RSA keys. They’re too close to each other, which makes them vulnerable to recovery. There aren’t many weak keys out there, but there are some: So far, Böck has identified only …

Researchers have found a major encryption flaw in 100 million Samsung Galaxy phones. From the abstract: In this work, we expose the cryptographic design and implementation of Android’s Hardware-Backed Keystore in Samsung’s Galaxy S8, S9, S10, S20, and S21 flagship devices. We reversed-engineered and provide a detailed …

Nice piece of research : Abstract: Among the many types of malicious codes, ransomware poses a major threat. Ransomware encrypts data and demands a ransom in exchange for decryption. As data recovery is impossible if the encryption key is not obtained, some companies suffer from considerable damage, such as the …

Bunnie Huang has created a Plausibly Deniable Database. Most security schemes facilitate the coercive processes of an attacker because they disclose metadata about the secret data, such as the name and size of encrypted files. This allows specific and enforceable demands to be made: “Give us the passwords for …

Late last year, the NSA declassified and released a redacted version of Lambros D. Callimahos’s Military Cryptanalytics, Part III. We just got most of the index. It’s hard to believe that there are any real secrets left in this 44-year-old volume. [...]

General Packet Radio Service (GPRS) is a mobile data standard that was widely used in the early 2000s. The first encryption algorithm for that standard was GEA-1, a stream cipher built on three linear-feedback shift registers and a non-linear combining function. Although the algorithm has a 64-bit key, the …

Nice video of a talk by Chris Shore on the history of Colossus. [...]

I have been seeing this paper by cryptographer Peter Schnorr making the rounds: “Fast Factoring Integers by SVP Algorithms.” It describes a new factoring method, and its abstract ends with the provocative sentence: “This destroys the RSA cryptosystem.” It does not. At best, it’s an improvement in factoring …

The NSA has just declassified and released a redacted version of Military Cryptanalytics, Part III, by Lambros D. Callimahos, October 1977. Parts I and II, by Lambros D. Callimahos and William F. Friedman, were released decades ago — I believe repeatedly, in increasingly unredacted form — and published by the late …