Trust messages can be used in conjunction with an end-to-end encryption protocol such as &xep0373; or &xep0384; to automatically or semi-automatically establish secure channels protected against active attacks.
This protocol specifies how trust messages are transmitted and protocols such as &xep0450; specify how and for which purpose they are processed.
In the following example, two &xep0384; keys of Alice are indicated as trusted, one key of Bob is indicated as trusted and two other ones of Bob are indicated as untrusted.
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<examplecaption='Trust Message Element for Alice's and Bob's OMEMO Keys'><![CDATA[
Protocols using trust messages SHOULD specify rules for processing them in order to create or sustain a secure communication.
Therefore, those protocols SHOULD state in which cases from which senders trust messages are used for making trust decisions and for which keys they are sent to whom.