Binding_message is a new parameter in OpenID Connect MODRNA Authentication Profile 1.0.
Binding_message is an Interlock message Binding the consumption Mobile Device and the authentication device together.
How to ensure that the message is actually shown on all relevant devices is out of the scope of the OpenID Connect MODRNA Authentication Profile 1.0 document. Possible values and constraints are specified in OpenID Connect MODRNA Authentication Profile 1.0 Section 7. Ways to protect the integrity of the Binding_message are discussed in OpenID Connect MODRNA Authentication Profile 1.0 Section 9.