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The logic behind this seems off? Signal and whastapp have different behaviors regarding this. (Signal does not have the issue of re-sending messages as was pre

by jknz 10y ago

The logic behind this seems off? Signal and whastapp have different behaviors regarding this. (Signal does not have the issue of re-sending messages as was previously reported here). This letter signed by a lot of very serious security cryptographers means that there is a consensus among the community about the "best" behavior in terms of security, trade-offs, etc. If there is indeed a consensus about what the "best" behavior is, then both Whatsapp and Signal should adopt this "best" behavior. However Whatsapp and Signal do not have adopted the same behavior. So the consensus does not seem to be there, otherwise both Whatsap and Signal would have adopted the "best" consensual behavior. So by first order logic... There is no consensus on this?

maxerickson 10y ago
They target different users.
tptacek 10y ago
No, that's not what the consensus is about. Many of the people who signed this letter disagree about what the ideal UX of a secure messenger is. It's not about ideal UX. Nobody knows what that UX is yet. WhatsApp is the first messenger with a world-scale userbase to tackle this problem; they're on the vanguard of work on this problem. Signal has a much smaller userbase and, importantly, that userbase adopts Signal specifically to get cryptographic security. Signal can innovate in different directions than WhatsApp, and WhatsApp can in the long term adopt the techniques Signal comes up with that actually work out. It's a good thing that there is both a messenger that protects a billion people without them having to understand public key crypto and another messenger that protects a much smaller number of people but that also serves as a laboratory for crypto UX. If you understand just one thing about the WhatsApp/Guardian dilemma, understand this: 99.99% of WhatsApp's users don't care about cryptographic security. They don't even know what that means. But that doesn't mean they don't need cryptographic security. Many of them need it badly whether they know it or not. But they're only going to use messengers that will allow them to talk to their peers, and none of their peers are on Signal. If you tell them WhatsApp is bad, they move to SMS.
idlewords 10y ago
The letter addresses this. The behavior is a trade-off, and you have to decide how to handle it. For a product with a billion users, where the threat model is mass surveillance, it is a good trade-off to never drop messages. For a product with more specialized users, who may be individually targeted, it is a good trade-off to not deliver buffered messages after a key change, and warn instead. There is no "best" behavior in the abstract, you have to take into account the setting.

by jknz 10y ago

maxerickson 10y ago

They target different users.

tptacek 10y ago

No, that's not what the consensus is about. Many of the people who signed this letter disagree about what the ideal UX of a secure messenger is. It's not about ideal UX. Nobody knows what that UX is yet. WhatsApp is the first messenger with a world-scale userbase to tackle this problem; they're on the vanguard of work on this problem. Signal has a much smaller userbase and, importantly, that userbase adopts Signal specifically to get cryptographic security. Signal can innovate in different directions than WhatsApp, and WhatsApp can in the long term adopt the techniques Signal comes up with that actually work out. It's a good thing that there is both a messenger that protects a billion people without them having to understand public key crypto and another messenger that protects a much smaller number of people but that also serves as a laboratory for crypto UX. If you understand just one thing about the WhatsApp/Guardian dilemma, understand this: 99.99% of WhatsApp's users don't care about cryptographic security. They don't even know what that means. But that doesn't mean they don't need cryptographic security. Many of them need it badly whether they know it or not. But they're only going to use messengers that will allow them to talk to their peers, and none of their peers are on Signal. If you tell them WhatsApp is bad, they move to SMS.

idlewords 10y ago

The letter addresses this. The behavior is a trade-off, and you have to decide how to handle it. For a product with a billion users, where the threat model is mass surveillance, it is a good trade-off to never drop messages. For a product with more specialized users, who may be individually targeted, it is a good trade-off to not deliver buffered messages after a key change, and warn instead. There is no "best" behavior in the abstract, you have to take into account the setting.