Off-the-Record Messaging

Privacy Levels

A conversation can have one of four privacy levels:

Alice and Bob are communicating with no cryptographic protection; they are not using OTR at all. Mallory, who is watching the network, can read everything they are saying to each other.

Alice and Bob are using OTR, and they have authenticated each other. They are assured that they are actually talking to each other, and not to an imposter. They are also confident that no one watching the network can read their messages.

Alice and Bob are using OTR, but they have not authenticated each other, which means they do not know for certain who they are talking to. It is possible that Mallory is impersonating one of them, or intercepting their conversation and reading everything they say to each other.

Alice was talking to Bob using OTR, but Bob has decided to stop using it. In this level, Alice is prevented from accidentally sending a private message without protection, by preventing her from sending any further messages to Bob at all. She must explicitly either end her side of the private conversation, or else start a new one.