In described examples, a method of routing messages in a system on a chip (SoC) includes a secure message router receiving a message including a content, an identifier of the message's sending (origin) functional block and/or of a receiving (destination) functional block, a message secure value, a promote value, and a demote value. A context corresponding to the identifier is retrieved from a memory. The context includes an allow promote value and an allow demote value. The message secure value is increased if the promote value requests the increase and matches the allow promote value. The message secure value is decreased if the demote value requests the decrease and matches the allow demote value. Cleartext corresponding to the content is made accessible by the destination if the context secure value matches the message secure value. The message is then outputted from the secure message router to the destination.