Entries Tagged "encryption"

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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 AMView 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 AMView Comments

Mary Queen of Scots Letters Decrypted

This is a neat piece of historical research.

The team of computer scientist George Lasry, pianist Norbert Biermann and astrophysicist Satoshi Tomokiyo—all keen cryptographers—initially thought the batch of encoded documents related to Italy, because that was how they were filed at the Bibliothèque Nationale de France.

However, they quickly realised the letters were in French. Many verb and adjectival forms being feminine, regular mention of captivity, and recurring names—such as Walsingham—all put them on the trail of Mary. Sir Francis Walsingham was Queen Elizabeth’s spymaster.

The code was a simple replacement system in which symbols stand either for letters, or for common words and names. But it would still have taken centuries to crunch all the possibilities, so the team used an algorithm that homed in on likely solutions.

Academic paper.

EDITED TO ADD (2/13): More news.

Posted on February 9, 2023 at 7:15 AMView Comments

Security Analysis of Threema

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. As one example, we present a cross-protocol attack which breaks authentication in Threema and which exploits the lack of proper key separation between different sub-protocols. As another, we demonstrate a compression-based side-channel attack that recovers users’ long-term private keys through observation of the size of Threema encrypted back-ups. We discuss remediations for our attacks and draw three wider lessons for developers of secure protocols.

From a news article:

Threema has more than 10 million users, which include the Swiss government, the Swiss army, German Chancellor Olaf Scholz, and other politicians in that country. Threema developers advertise it as a more secure alternative to Meta’s WhatsApp messenger. It’s among the top Android apps for a fee-based category in Switzerland, Germany, Austria, Canada, and Australia. The app uses a custom-designed encryption protocol in contravention of established cryptographic norms.

The company is performing the usual denials and deflections:

In a web post, Threema officials said the vulnerabilities applied to an old protocol that’s no longer in use. It also said the researchers were overselling their findings.

“While some of the findings presented in the paper may be interesting from a theoretical standpoint, none of them ever had any considerable real-world impact,” the post stated. “Most assume extensive and unrealistic prerequisites that would have far greater consequences than the respective finding itself.”

Left out of the statement is that the protocol the researchers analyzed is old because they disclosed the vulnerabilities to Threema, and Threema updated it.

Posted on January 19, 2023 at 7:21 AMView Comments

ChatGPT-Written Malware

I don’t know how much of a thing this will end up being, but we are seeing ChatGPT-written malware in the wild.

…within a few weeks of ChatGPT going live, participants in cybercrime forums—­some with little or no coding experience­—were using it to write software and emails that could be used for espionage, ransomware, malicious spam, and other malicious tasks.

“It’s still too early to decide whether or not ChatGPT capabilities will become the new favorite tool for participants in the Dark Web,” company researchers wrote. “However, the cybercriminal community has already shown significant interest and are jumping into this latest trend to generate malicious code.”

Last month, one forum participant posted what they claimed was the first script they had written and credited the AI chatbot with providing a “nice [helping] hand to finish the script with a nice scope.”

The Python code combined various cryptographic functions, including code signing, encryption, and decryption. One part of the script generated a key using elliptic curve cryptography and the curve ed25519 for signing files. Another part used a hard-coded password to encrypt system files using the Blowfish and Twofish algorithms. A third used RSA keys and digital signatures, message signing, and the blake2 hash function to compare various files.

Check Point Research report.

ChatGPT-generated code isn’t that good, but it’s a start. And the technology will only get better. Where it matters here is that it gives less skilled hackers—script kiddies—new capabilities.

Posted on January 10, 2023 at 7:18 AMView Comments

Apple Is Finally Encrypting iCloud Backups

After way too many years, Apple is finally encrypting iCloud backups:

Based on a screenshot from Apple, these categories are covered when you flip on Advanced Data Protection: device backups, messages backups, iCloud Drive, Notes, Photos, Reminders, Safari bookmarks, Siri Shortcuts, Voice Memos, and Wallet Passes. Apple says the only “major” categories not covered by Advanced Data Protection are iCloud Mail, Contacts, and Calendar because “of the need to interoperate with the global email, contacts, and calendar systems,” according to its press release.

You can see the full list of data categories and what is protected under standard data protection, which is the default for your account, and Advanced Data Protection on Apple’s website.

With standard data protection, Apple holds the encryption keys for things that aren’t end-to-end encrypted, which means the company can help you recover that data if needed. Data that’s end-to-end encrypted can only be encrypted on “your trusted devices where you’re signed in with your Apple ID,” according to Apple, meaning that the company—or law enforcement or hackers—cannot access your data from Apple’s databases.

Note that this system doesn’t have the backdoor that was in Apple’s previous proposal, the one put there under the guise of detecting CSAM.

Apple says that it will roll out worldwide by the end of next year. I wonder how China will react to this.

Posted on December 12, 2022 at 7:00 AMView Comments

Charles V of Spain Secret Code Cracked

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 Arabic.

In another obstacle, he used meaningless symbols to mislead any adversary trying to decipher the message.

The breakthrough came in June when Pierrot managed to make out a phrase in the letter, and the team then cracked the code with the help of Camille Desenclos, a historian. “It was painstaking and long work but there was really a breakthrough that happened in one day, where all of a sudden we had the right hypothesis,” she said.

Posted on November 29, 2022 at 7:19 AMView Comments

Breaking the Zeppelin Ransomware Encryption Scheme

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 ephemeral RSA-512 public key that is randomly generated on each machine it infects.

“If we can recover the RSA-512 Public Key from the registry, we can crack it and get the 256-bit AES Key that encrypts the files!” they wrote. “The challenge was that they delete the [public key] once the files are fully encrypted. Memory analysis gave us about a 5-minute window after files were encrypted to retrieve this public key.”

Unit 221B ultimately built a “Live CD” version of Linux that victims could run on infected systems to extract that RSA-512 key. From there, they would load the keys into a cluster of 800 CPUs donated by hosting giant Digital Ocean that would then start cracking them. The company also used that same donated infrastructure to help victims decrypt their data using the recovered keys.

A company offered recovery services based on this break, but was reluctant to advertise because it didn’t want Zeppelin’s creators to fix their encryption flaw.

Technical details.

EDITED TO ADD (12/12): When BitDefender publicly advertised a decryption tool for a strain of DarkSide ransomware, DarkSide immediately updated its ransomware to render the tool obsolete. It’s hard to come up with a solution to this problem.

Posted on November 21, 2022 at 7:08 AMView Comments

Hyundai Uses Example Keys for Encryption System

This is a dumb crypto mistake I had not previously encountered:

A developer says it was possible to run their own software on the car infotainment hardware after discovering the vehicle’s manufacturer had secured its system using keys that were not only publicly known but had been lifted from programming examples.


“Turns out the [AES] encryption key in that script is the first AES 128-bit CBC example key listed in the NIST document SP800-38A [PDF]”.


Luck held out, in a way. “Greenluigi1” found within the firmware image the RSA public key used by the updater, and searched online for a portion of that key. The search results pointed to a common public key that shows up in online tutorials like “RSA Encryption & Decryption Example with OpenSSL in C.

EDITED TO ADD (8/23): Slashdot post.

Posted on August 22, 2022 at 6:38 AMView Comments

SIKE Broken

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 existence of a small non-scalar endomorphism on the starting curve, and it also relies on the auxiliary torsion point information that Alice and Bob share during the protocol. Our Magma implementation breaks the instantiation SIKEp434, which aims at security level 1 of the Post-Quantum Cryptography standardization process currently ran by NIST, in about one hour on a single core.

News article.

Posted on August 4, 2022 at 6:56 AMView Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.