# Tag Info

## New answers tagged protocol-design

3

The properties you list do not suffice for traitor-tracing, since it's not necessarily easy to find a compatible key from a leaked circuit. In particular, if the traitor tracing property holds and key generation process produces keys that satisfy the equality property for all $x$, then indistinguishability obfuscation of the functions $\: x\mapsto ... 0 Introducing three modifications: Assume part of a client's "real identity" is a public key$U_P$, generated by the client There exists an oracle$V$acting as a verifier The server gives each client its public key$S_P$If the clients know each other, or some of the others, they can also verify they all have the same$S_P$. Setup:$S$makes the list of ... 0 If "S assigns to each of them a unique identifier" then S could just run the claim algorithm with each of those identifiers to find out who a given claim was from. Something similar would be to have S blindly sign a perfectly binding commitment that is generated by the client, to the identifier that is assigned by the server. 3 Your simple approach is not bad, but you might consider these modifications: First, you don't need a PRF, any form of hashed key or a simple hash over the concatenation of a key and the element should be enough. Basically any one-way function over elements and some sort of key should do the trick, and you can optimize for speed. The key is not chosen by ... 4 The claims made are pretty much all nonsense or do not represent an accurate understanding of the state of the art. I'm not going to go into a point-by-point response; suffice it to say that I would not trust any advice or representations they may make about what is or isn't secure. Their system might be fine, or it might not be, but their public ... 11 I'll comment only the statement referring to an AES-256 replacement with 4096-bit key: According to our engineers, this will take 23840 times longer to crack than aes256 Bob writing that is not able to correctly transcribe even the numbers that engineer Alice allegedly spelled: most likely,$23840$is intended to be$2^{3840}\$, which is the ratio ...

1

I think the very first question before diving into designing the protocol would be to ask yourself what kind of secure communication do you want? Namely, there are two options to consider when it comes to communication between the IM users: For the client-server secure communication, there are two directions to consider: From “sender to server”, you ...

0

Yes, like there are conventional signcryption schemes combining digital signatures with encryption into a single primitive, there are also ring signcryption schemes that realize the same for ring signatures and encryption. Look for instance here or just ask Google scholar.

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