[转载] Combating abuse in Matrix - without backdoors. - 可打印的版本 +- WeHack BBS (https://bbs.wehack.space) +-- 版块: 计算机技术 (https://bbs.wehack.space/forum-5.html) +--- 版块: 网络技术与信息安全讨论区 (https://bbs.wehack.space/forum-7.html) +--- 主题: [转载] Combating abuse in Matrix - without backdoors. (/thread-189.html) |
[转载] Combating abuse in Matrix - without backdoors. - vimacs - 10-22-2020 2020-10-19 — Matthew Hodgson Hi all, Last Sunday, the UK Government published an international statement on end-to-end encryption and public safety, co-signed by representatives from the US, Australia, New Zealand, Canada, India and Japan. The statement is well written and well worth a read in full, but the central point is this: 引用:We call on technology companies to [...] enable law enforcement access to content in a readable and usable format where an authorisation is lawfully issued, is necessary and proportionate, and is subject to strong safeguards and oversight.In other words, this is an explicit request from seven of the biggest governments in the world to mandate a backdoor in end-to-end encrypted (E2EE) communication services: a backdoor to which the authorities have a secret key, letting them view communication on demand. This is big news, and is of direct relevance to Matrix as an end-to-end encrypted communication protocol whose core team is currently centred in the UK. Now, we sympathise with the authorities’ predicament here: we utterly abhor child abuse, terrorism, fascism and similar - and we did not build Matrix to enable it. However, trying to mitigate abuse with backdoors is, unfortunately, fundamentally flawed.
We’re not alone in thinking this either: the GDPR (the world-leading regulation towards data protection and privacy) explicitly calls out robust encryption as a necessary information security measure. In fact, the risk of US governmental backdoors explicitly caused the European Court of Justice to invalidate the Privacy Shield for EU->US data. The position of the seven governments here (alongside recent communications by the EU commissioner on the ‘problem’ of encryption) is a significant step back on the protection of the fundamental right of privacy. So, how do we solve this predicament for Matrix? Thankfully: there is another way. This statement from the seven governments aims to protect the general public from bad actors, but it clearly undermines the good ones. What we really need is something that empowers users and administrators to identify and protect themselves from bad actors, without undermining privacy. What if we had a standard way to let users themselves build up and share their own views of whether other users, messages, rooms, servers etc. are obnoxious or not? What if you could visualise and choose which filters to apply to your view of Matrix? Just like the Web, Email or the Internet as a whole, there is literally no way to unilaterally censor or block content in Matrix. But what we can do is provide first-class infrastructure to let users (and room/community moderators and server admins) make up their own mind about who to trust, and what content to allow. This would also provide a means for authorities to publish reputation data about illegal content, providing a privacy-respecting mechanism that admins/mods/users can use to keep illegal content away from their servers/clients. The model we currently have in mind is:
In terms of how this interacts with end-to-end-encryption and mitigating abuse: the reality is that the vast majority of abuse in public networks like Matrix, the Web or Email is visible from the public unencrypted domain. Abusive communities generally want to attract/recruit/groom users - and that means providing a public front door, which would be flagged by a reputation system such as the one proposed above. Meanwhile, communities which are entirely private and entirely encrypted typically still have touch-points with the rest of the world - and even then, the chances are extremely high that they will avoid any hypothetical backdoored servers. In short, investigating such communities requires traditional infiltration and surveillance by the authorities rather than an ineffective backdoor. Now, this approach may sound completely sci-fi and implausibly overambitious (our speciality!) - but we’ve actually started successfully building this already, having been refining the idea over the last few years. MSC2313 is a first cut at the idea of publishing and subscribing to reputation data - starting off with simple binary ban rules. It’s been implemented and in production for over a year now, and is used to maintain shared banlists used by both matrix.org and mozilla.org communities. The next step is to expand this to support a blendable continuum of reputation data (rather than just binary banlists), make it privacy preserving, and get working on the client UX for configuring and visualising them. Finally: we are continuing to hire a dedicated Reputation Team to work full time on building this (kindly funded by Element). This is a major investment in the future of Matrix, and frankly is spending money that we don’t really have - but it’s critical to the long-term success of the project, and perhaps the health of the Internet as a whole. There’s nothing about a good relative reputation system which is particularly specific to Matrix, after all, and many other folks (decentralised and otherwise) are clearly in desperate need of one too. We are actively looking for funding to support this work, so if you’re feeling rich and philanthropic (or a government wanting to support a more enlightened approach) we would love to hear from you at [email protected]! Here’s to a world where users have excellent tools to protect themselves online - and a world where their safety is not compromised by encryption backdoors. -- The Matrix.org Core Team |