Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [signal-protocol]

The Signal (formerly known as TextSecure) Protocol is an end-to-end encryption protocol developed for the instant messaging software Signal and also used by other software such as WhatsApp.

0
votes
2answers
61 views

Purpose of key evolution?

When generating and exchanging keys, what is the purpose of performing key evolution after public key exchange + authenticated encryption?
1
vote
1answer
68 views

Signal Protocol - Counter over TCP?

Signal Protocol uses a counter (discussed in DoubleRatchet documentation) to define how many times KDF has derived a new key (aka a KDF step) which is then sent along with every message for the end ...
4
votes
0answers
172 views

Why does the Signal protocol use AES/CBC instead of AES/GCM?

AES/GCM has obviously proved itself to be better than AES/CBC. Unless the key is re-used with the same initialization vector (see disadvantages of GCM). More information of its advantages against CBC ...
0
votes
1answer
81 views

Signal protocol: when, and why, is X3DH run again between the same two users?

This question concerns the Signal protocol's X3DH key agreement protocol as documented here. Obviously, if Alice and Bob have never contacted each other before, they need to run X3DH at least once to ...
1
vote
1answer
279 views

Signal Protocol: What extra features does double ratchet algorithm add to Diffie-Hellman ratchet?

I have been reading the documentation of Signal protocol and could not find out why they came up with double ratchet instead of using Diffie-Hellman ratchet which was available at first place in OTR?
1
vote
1answer
67 views

Signal/TextSecure multiparty Chat. Does the protocol transmits a symmetric key?

As I look over the TexSecures specifications for multi-party chat I have noticed this. Also as far as I understood in TextSecure (now known as Signal) the minimal steps required to do a secure ...
3
votes
1answer
125 views

How does future secrecy fail for Signal group messaging?

In the paper More is Less: On the End-to-End Security of Group Chats in Signal, WhatsApp, and Threema, the abstract claims that We additionally show that strong security properties, such as ...
2
votes
1answer
499 views

Is it possible to implement the Signal Protocol without a server?

My question is regarding the Signal Protocol[1]. Is it possible to implement the protocol securely, without a server? (I have no particular motivation for the question other than to understand better ...
3
votes
1answer
304 views

Signal Double Ratchet - How can Alice send 2+ messages in the beginning of the Signal Protocol?

I'm studying about Signal Protocol and I had a doubt in Double Ratchet Algorithm. This section describes how to derive the receiving and sending key messages. Alice is initialized by Bob public ...
9
votes
1answer
2k views

What is the difference between OTR and Signal protocols?

The Signal Protocol is a relatively new secure messaging protocol that was recently implemented in Signal, WhatsApp, and several other messenging apps. According to Wikipedia, the Signal protocol is ...