Questions tagged [otr]

For questions about Off-The-Record Messaging, which is a technique which allows you to have private conversations over instant messaging.

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2 votes
0 answers
43 views

Off-The-Record and Multi-Designated Verifier Signatures

What technique is used in the Off-The-Record protocol to implement authentication and message validation? And what is the difference between this technique and Multi-Designated Verifier Signatures? ...
14 votes
2 answers
3k 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 ...
5 votes
2 answers
1k views

Is OMEMO vulnerable in case of compromised jabber server?

As I've understand OMEMO protocol specification, the initial key exchange between Alice and Bob can be stored on server and in future used for message decryption. Also the phrase from Conversations, ...
0 votes
2 answers
1k views

How do Alice and Bob perform key exchange through a third-party (server) in end-to-end encryption?

Understanding end-to-end encryption, I ran into an issue which I wasn't able to find a solution for. Given three parties: Alice, Bob, the chat endpoints, and the server party owned by Eve. The server ...
0 votes
1 answer
246 views

Isn't Socialist Millionaires vulnerable if Alice's and Bob's message are picked from a shared list?

I'm interested in a situation where Alice and Bob each pick cards from a deck of 52, and want to test if they picked the same card without revealing what the card is (a "mental poker" situation). The ...
5 votes
1 answer
331 views

How to compute result in last step of Socialist millionaires problem?

I was trying to understand Socialist millionaires problem and solution in OTR protocol, but I'm stuck at figuring out how and who computes $(Q_{a}Q_b{}^{-1})^{\alpha\beta}$. If I'm Bob then I received ...
2 votes
1 answer
177 views

A clarification about OTR shared secrets - how long need they be secret?

A quick question on confirmation/authentication with the OTR protocol. OTR shared secrets/Q&A when used to authenticate your partner in conversation, am I correct my understanding that they DO ...
1 vote
1 answer
346 views

Would this authentication on a Diffie-Hellmann-key-exchanged channel work?

Before I ask my question, let me say that I don't know the math behind OTR, so I don't know if the process of authentication in OTR is any similar to this. Alice and Bob have exchanged keys using ...
2 votes
1 answer
896 views

How secure is the OTR protocol?

I am using Adium and wondering how secure it is. I believe it uses AES-256 (I do not understand what that means) by default. It also requests that users exchange fingerprints with each other before ...