ContactDiscoveryService VS Mechanics-of-MobileCoin

[1] https://signal.org/blog/private-contact-discovery/

Signal uses SGX for remote attestation, which presumably lets the client verify that the code running on the server is a build of the OSS code and not a modified version. But I don't know the details or if this is reliable.

SGX and remote attestation described here:

https://signal.org/blog/private-contact-discovery/

Signal does private contact discovery and the effort they've gone to to do this is quite impressive.

TEEs have numerous privacy-enhancing applications that may benefit users. One of them is, as discussed earlier, private contact discovery; the Signal application uses a contact discovery service enhanced using Intel SGX, a TEE technology, to protect its users' privacy. A similar application of TEEs is performing malware analysis in a remote cloud service, so that the service may not identify users by the contents of their devices, such as the applications they have installed, especially important as 98.93% of users may be uniquely identified by the list of applications they have installed.

Signal (or, more accurately, one of its predecessors) used to use client-side private set intersection for contact discovery, but this scales poorly [1].

Now they use a solution based on Intel SGX and server-side trusted computing [2].

[1] https://signal.org/blog/contact-discovery/

[2] https://signal.org/blog/private-contact-discovery/

Source: a book-length overview of MobileCoin written by a respected member of the Monero community.

Seems like this isn't getting much circulation yet, not the easiest thing to find despite its importance. The Mechanics of MobileCoin, First Edition published April 6, 2021.

That's not the official whitepaper, this is a very outdated spec - this is the latest up-to-date whitepaper https://github.com/UkoeHB/Mechanics-of-MobileCoin/blob/master/Mechanics-of-MobileCoin-v0-0-39-preview-10-11.pdf

Blockchains can use DAGs. Check out this pdf document which you can find in this github repo. It explains some details of mobile coin.

It is based on monero, from their whitepaper edit of zero to monero it looks to be Monero + Stellar Consensus with SGX so they're trading some privacy and a lot of decentralisation for speed.

This whitepaper is not the whitepaper I wrote back in 2017. We took that down because it was ultimately not the design we implemented. The full system design can be found here: https://github.com/UkoeHB/Mechanics-of-MobileCoin/blob/maste....