Comment by walterbell | Hacker News Reader

Comment by walterbell | Hacker News Reader

IETF MLS (https://datatracker.ietf.org/wg/mls/about/) was ratified in September 2022 by messenger service vendors (including Wire, Matrix, Mozilla, Cisco, Google, Facebook), who have been working for several years on an E2EE group messaging protocol to live alongside TLS. MLS is already deployed in production by Cisco WebEx.

> Messaging applications are increasingly making use of end-to-end security mechanisms to ensure that messages are only accessible to the communicating endpoints, and not to any servers involved in delivering messages. Establishing keys to provide such protections is challenging for group chat settings, in which more than two clients need to agree on a key but may not be online at the same time. In this document, we specify a key establishment protocol that provides efficient asynchronous group key establishment with forward secrecy and post-compromise security for groups in size ranging from two to thousands.

There is now a follow-up IETF project to use MLS for inter-messenger interoperability, with Matrix as an early participant, https://news.ycombinator.com/item?id=33420112

Review of 2020 draft protocol, https://liu.diva-portal.org/smash/get/diva2:1388449/FULLTEXT...

> Work is now ongoing to introduce the Messaging Layer Security (MLS) protocol as an efficient standard with high security guarantees for messaging in big groups. This thesis examines whether current MLS implementations live up to the promised performance properties and compares them to the popular Signal protocol. In general the performance results of MLS are promising and in line with expectations, providing improved performance compared to the Signal protocol as group sizes increase.

Notably, this design lacks reputability, which for some reason they didn't even want (as it might be used by "terrorists"), which led to arguments with Ian Goldberg, the developer of Off-the-Record messaging. The arguments on the big tracker about power imbalances were maybe a bit better, but I still personally disagree.

https://mailarchive.ietf.org/arch/msg/mls/ZJ4e78obXSdYWnxmsN...

https://github.com/mlswg/mls-architecture/issues/50

While deniability would be welcome, the last few years have seen rumblings from various Australia/UK/US stakeholders about possible regulation for E2EE messenger intercept, i.e. even encryption would be compromised in that scenario. Hopefully the recent Apple announcement on E2EE iCloud means that regulators have seen the folly of mass interception.

If China (e.g. WeChat) is a predictor of future messaging systems, there may be convergence between messaging and payments. Musk has publicly suggested that Twitter follow in WeChat's footsteps as an "Everything App". If payments and messaging converge, and governments adopt CBDCs for digital legal tender, then we may be looking down the barrel of state-issued digital IDs for online and offline activity.

Linux Foundation is promoting blockchain for both software signing and globally interoperable travel/health credentials. Big tech companies each have their own island of semi-verified identities, depending on their proximity to financial services. It's not clear which groups are willing or able to effectively lobby for pseudonymous digital identity.

> reputability

The word you’re looking for is “repudiability.”

Although one might say that lacking repudiability could be enough for a messaging system to lack reputability ;)

> a follow-up IETF project to use MLS for inter-messenger interoperability

It's worth highlighting (as a comment in the linked discussion does) that the EU's newly-passed Digital Markets Act requires interoperability between the messaging apps of large "gatekeeper" platforms.

If Twitter does end up supporting E2EE messaging, it may soon be forced to implement MLS, and if Facebook and Google are really supportive of MLS then soon(TM) most people online will be able to communicate via that technology.

> Messaging applications are increasingly making use of end-to-end security mechanisms to ensure that messages are only accessible to the communicating endpoints, and not to any servers involved in delivering messages.

You have to put trust in the app (and the company that owns that app), though.

In twitter, I type a message in plain text. The twitter app encrypts it and sends it to the recipient. I am trusting Twitter to not encrypt it twice, once with my key and once with there's and capturing their copy in flight.

With current trends at Twitter, I wouldn't trust them an inch.

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