Proof of authenticity of messages

Hello!

I just found out about jami. So, I have not so much an idea as a question. Maybe it’s already implemented.

Let’s say Alice exchanges messages with Bob using jami. Will Alice later be able to prove to some third party the authenticity of the messages sent and received? Authenticity refers to the authorship, time point and content of messages.

As far as I know Bob CAN enable the option “Enable read receipts” so that Alice knows that Bob read the message.

Thank you. But I need more. Alice must be able to prove to a third party (not Bob) that she sent a message to Bob, including the content and timepoint of the message.

My use case:

Alice and Bob establish a contractual relationship with the help of correspondence in the messenger. It may happen that later Alice and Bob interpret the meaning of the agreements differently. In case of disagreement, Alice and Bob agreed to involve the arbiter Tom. Alice reaches out to him and provides the correspondence with Bob. How can Tom make sure that Alice didn’t falsify the correspondence with Bob? Bob could authenticate the correspondence, but he refuses to cooperate.

Any swarm is a repository of messages where all messages are signed by the sender’s and all certificates to rebuild the history is in the repo. It’s a classic x509 cert chain.

Is it already implemented in Jami? If not, do you know any messenger where it is implemented?