isn't the "double ratchet" describing the presence of both a DH ratchet as well as a hash ratchet, rather than "send" and "receive"?
How the Textsecure Protocol Works
21–30 of 87 posts
Re: How the Textsecure Protocol Works
#22> Instead, copies of the server's role in the key negotiation are stored by a centralized server for potential clients to fetch and use. This "centralised" and "server" are just about the worst words you want to hear in the description of a system like this and yet they are just thrown in there in a flippant comment at the end of a section? I think a more detailed description of this glorified cache is warranted.
The server role seems quite clearly described in more detail in the actual protocol description, is there something missing? The section you quote just describes the high-level idea of why and how to introduce the server in the scheme.
No. If the section beginning "Protocol" is what you refer to as the "actual protocol description" then no, the server role does not seem clearly described in any level of detail.
To cut a long story short: Alice gives the cache, aka Mallory, a set of secret data which are implied but not proven to be able to be used by Bob to create cryptographic text which Alice can decrypt but this magic cache, aka Mallory, cannot. This document provides few hints and no detail on how we can be assured that the magic cache, A.K.A. MALLORY, is unable to make use of the secret data provided by Alice (and "promised not to be shared") to make inferrences on the crypyographic text provided by Bob.
Re: How the Textsecure Protocol Works
#23Earlier quoted context omitted.
There's nothing preventing Whatsapp from releasing an update that has a flag on your phone number/id that turns off e2e for messages that you send. If their software was open source we would be able to verify what we are running but as it stands, it's not and I doubt it will ever be.
Open source is a red herring. You're downloading WhatsApp from an app store (or, at least, the overwhelming majority of users are). If you can't verify what the binary is doing, the source code doesn't make a difference. Beyond that, despite the repeated claims of open source advocates, there's nothing preventing people from taking the app store versions of things like WhatsApp and reverse engineering them.
Obviously the app maintainer could push an update that simply leaks your keys and stored messages. Doesn't matter if it's open or closed source.
However, open source does give users some real recourse in the event that the project moves in an undesirable direction. I don't like what's happening, I can fork it without your permission and still have access to the same development environment and build tools the original project had. I think that's important and valuable.
Re: How the Textsecure Protocol Works
#24Re: How the Textsecure Protocol Works
#25Earlier quoted context omitted.
Open source is a red herring. You're downloading WhatsApp from an app store (or, at least, the overwhelming majority of users are). If you can't verify what the binary is doing, the source code doesn't make a difference. Beyond that, despite the repeated claims of open source advocates, there's nothing preventing people from taking the app store versions of things like WhatsApp and reverse engineering them.
If builds were reproducible (i.e. binaries would be identical if recompiled with the same toolchain on a different machine), then all it would take is N independent builders to verify the app store binary matches their locally built binary to greatly decrease the likelihood of tampering. So, while being open source is not the complete answer, it certainly doesn't hurt.
How do you guarantee the App Store doesn't serve limited edition binaries to selected recipients?
Re: How the Textsecure Protocol Works
#26Re: How the Textsecure Protocol Works
#27Nice overview. I only wish for there to be an implementation of the signal protocol that fits my needs. In WhatsApp and Allo there are concerns of ad companies using your metadata, and the Signal app is lackluster in the UX department and OWS's affinity with Google is rather disappointing also.
Wire seems fairly fully featured, open source, and claim to have a feasible "freemium" business model, i.e. later selling premium services on the platform. They claim they use the Axolotl double ratchet, though Moxie/OWS claims Wire uses a variation of the protocol they don't recommend.
I would be interested to know exactly what it is about Wire that OWS doesn't seem to approve of
Re: How the Textsecure Protocol Works
#28> Instead, copies of the server's role in the key negotiation are stored by a centralized server for potential clients to fetch and use. This "centralised" and "server" are just about the worst words you want to hear in the description of a system like this and yet they are just thrown in there in a flippant comment at the end of a section? I think a more detailed description of this glorified cache is warranted.
Oh it's not warranted is it? Does whichever butthurt shill clicked that button want to suggest why we don't need more detail on which central server stores what in this self-proclaimed "secure" system?
Perhaps people are responding to your unwarranted, toxic tone, your rudeness elsewhere in the comments, and your inability to give even a modicum of respect to the developers who've not only designed and openly published groundbreaking advances in secure private messaging protocols, and not only implemented them and freely distributed those implementations, but have also worked to have those designs incorporated into the some of the most widely-used messaging software in history.
Re: How the Textsecure Protocol Works
#29[deleted]
Re: How the Textsecure Protocol Works
#30Earlier quoted context omitted.
Wire seems fairly fully featured, open source, and claim to have a feasible "freemium" business model, i.e. later selling premium services on the platform. They claim they use the Axolotl double ratchet, though Moxie/OWS claims Wire uses a variation of the protocol they don't recommend.
I would be interested to know exactly what it is about Wire that OWS doesn't seem to approve of
It might just be that they did not look into it.