Category Archives: backdoors

New German Government is Pro-Encryption and Anti-Backdoors

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I hope this is true:

According to Jens Zimmermann, the German coalition negotiations had made it “quite clear” that the incoming government of the Social Democrats (SPD), the Greens and the business-friendly liberal FDP would reject “the weakening of encryption, which is being attempted under the guise of the fight against child abuse” by the coalition partners.

Such regulations, which are already enshrined in the interim solution of the ePrivacy Regulation, for example, “diametrically contradict the character of the coalition agreement” because secure end-to-end encryption is guaranteed there, Zimmermann said…

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Security Risks of Client-Side Scanning

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Even before Apple made its announcement, law enforcement shifted their battle for backdoors to client-side scanning. The idea is that they wouldn’t touch the cryptography, but instead eavesdrop on communications and systems before encryption or after decryption. It’s not a cryptographic backdoor, but it’s still a backdoor — and brings with it all the insecurities of a backdoor.

I’m part of a group of cryptographers that has just published a paper discussing the security risks of such a system. (It’s substantially the same group that wrote a similar paper about …

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More on Apple’s iPhone Backdoor

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In this post, I’ll collect links on Apple’s iPhone backdoor for scanning CSAM images. Previous links are here and here.

Apple says that hash collisions in its CSAM detection system were expected, and not a concern. I’m not convinced that this secondary system was originally part of the design, since it wasn’t discussed in the original specification.

Good op-ed from a group of Princeton researchers who developed a similar system:

Our system could be easily repurposed for surveillance and censorship. The design wasn’t restricted to a specific category of content; a service could simply swap in any content-matching database, and the person using that service would be none the wiser…

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Apple’s NeuralHash Algorithm Has Been Reverse-Engineered

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Apple’s NeuralHash algorithm — the one it’s using for client-side scanning on the iPhone — has been reverse-engineered.

Turns out it was already in iOS 14.3, and someone noticed:

Early tests show that it can tolerate image resizing and compression, but not cropping or rotations.

We also have the first collision: two images that hash to the same value.

The next step is to generate innocuous images that NeuralHash classifies as prohibited content.

This was a bad idea from the start, and Apple never seemed to consider the adversarial context of the system as a whole, and not just the cryptography…

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Apple Adds a Backdoor to iMessage and iCloud Storage

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Apple’s announcement that it’s going to start scanning photos for child abuse material is a big deal. (Here are five news stories.) I have been following the details, and discussing it in several different email lists. I don’t have time right now to delve into the details, but wanted to post something.

EFF writes:

There are two main features that the company is planning to install in every Apple device. One is a scanning feature that will scan all photos as they get uploaded into iCloud Photos to see if they match a photo in the database of known child sexual abuse material (CSAM) maintained by the National Center for Missing & Exploited Children (NCMEC). The other feature scans all iMessage images sent or received by child accounts — that is, accounts designated as owned by a minor — for sexually explicit material, and if the child is young enough, notifies the parent when these images are sent or received. This feature can be turned on or off by parents…

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Intentional Flaw in GPRS Encryption Algorithm GEA-1

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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 effective key length is only 40 bits, due to “an exceptional interaction of the deployed LFSRs and the key initialization, which is highly unlikely to occur by chance.”

GEA-1 was designed by the European Telecommunications Standards Institute in 1998. ETSI was — and maybe still is — under the auspices of …

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FBI/AFP-Run Encrypted Phone

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For three years, the Federal Bureau of Investigation and the Australian Federal Police owned and operated a commercial encrypted phone app, called AN0M, that was used by organized crime around the world. Of course, the police were able to read everything — I don’t even know if this qualifies as a backdoor. This week, the world’s police organizations announced 800 arrests based on text messages sent over the app. We’ve seen law enforcement take over encrypted apps before: for example, EncroChat. This operation, code-named Trojan Shield, is the first time law enforcement managed an app from the beginning…

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Bizarro Banking Trojan

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Bizarro is a new banking trojan that is stealing financial information and crypto wallets.

…the program can be delivered in a couple of ways­ — either via malicious links contained within spam emails, or through a trojanized app. Using these sneaky methods, trojan operators will implant the malware onto a target device, where it will install a sophisticated backdoor that “contains more than 100 commands and allows the attackers to steal online banking account credentials,” the researchers write.

The backdoor has numerous commands built in to allow manipulation of a targeted individual, including keystroke loggers that allow for harvesting of personal login information. In some instances, the malware can allow criminals to commandeer a victim’s crypto wallet, too…

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