1. Exquisite Tweets from @musalbas

    PreoccupationsCollected by Preoccupations

    Oh wow, remember that hoopla about the WhatsApp design decision which re-encrypts undelivered messages to a new key, if someone has your SIM card? Ian Levy, director at GCHQ, suggests making use of this as a feature for police to get access to messages. youtube.com/watch?v=LRiAcb…

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    musalbas

    Mustafa Al-Bassam

    Ian Levy of GCHQ has released an essay on how law enforcement should get access to end-to-end encrypted communications. Here is the critical bit to pay attention to.

    They're proposing to exploit the fact that users don't verify each other's public keys, and inject bad keys.

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    musalbas

    Mustafa Al-Bassam

    We've been fortunate enough to not have a global active adversary that is willing to manipulate packets on a large scale, so end-to-end encrypted chat systems didn't have to focus much on the key verification problem. That looks like it's going to change: twitter.com/musalbas/statu…

    musalbas

    Mustafa Al-Bassam

    In light of this, user-friendly key verification is going to be increasingly important, as will systems such as Key Transparency which make it so that any misbehaviour on the part of the server in key management will be publicly detectable, even if users don't verify keys.

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    musalbas

    Mustafa Al-Bassam

    This is the type of notification from WhatsApp for example that Levy is likely talking about suppressing, and also any notifications that would inform you when a new device has been added to your account.

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    musalbas

    Mustafa Al-Bassam

    Here is what Levy also said earlier this year in relation to identity systems in end-to-end encryption messaging apps. Thread from earlier this year: twitter.com/musalbas/statu…

    musalbas

    Mustafa Al-Bassam

    Also these notifications would be surpressed under GCHQ's law enforcement access proposal:

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    musalbas

    Mustafa Al-Bassam