Signal adds a payments feature with a privacy-focused cryptocurrency

Re:Signal adds a payments feature with a privacy-focused cry... by Ar-Curunir on Wednesday April 07, 2021 @07:21AM (#26723243)

the usage of SGX here is to protect against a fairly benign adversary: Signal themselves. The alternative to using SGX in these situations is to hand over the data in the clear to Signal servers.

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Re:Signal adds a payments feature with a privacy-focused cry... by codethief on Wednesday April 07, 2021 @02:52PM (#26729266)

> a fairly benign adversary

Given the Snowden leaks and everyone's experience with what Facebook etc. do with our data, I wouldn't call that a "benign" adversary at all. Besides, even if Signal itself is benign, someone who manages to hack the Signal infrastructure might not be.

> The alternative to using SGX in these situations is to hand over the data in the clear to Signal servers.

This is not correct. The alternative would be to tell users to choose a passphrase with enough entropy. In that case, SGX wouldn't be necessary. Unfortunately, they didn't do that, so now a lot of users have chosen a short PIN and their data will be compromised should SGX ever fail to live up to its promises. (This is what I meant by "Signal PIN UI fuckup" – the word "PIN" alone suggests choosing a short number over a long passphrase.)

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Re:Signal adds a payments feature with a privacy-focused cry... by Ar-Curunir on Wednesday April 07, 2021 @05:48PM (#26731814)

Sorry, the use case I had in mind was contact discovery. Existing cryptographic protocols for private contact discovery do not scale to Signal’s numbers.

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