MTRP security is designed to be practical for small embedded devices while leaving room for stronger profiles on more capable nodes.

MTRP distinguishes between:

• routing and transport behavior
• security capability and trust behavior

This allows different transports and device classes to participate at different security levels.

Security capability values describe what a node or transport can support.

Examples include:

• NONE
• AES128
• AES256

For constrained devices, even basic security and message authenticity are better than none.

For more capable nodes, stronger validation and key handling can be layered in later.

The network ID is still useful even in secure deployments.

It helps separate intentional protocol traffic from unrelated local radio traffic before deeper validation is performed.

MTRP does not currently provide:

• full end-to-end authenticated delivery
• group-message security semantics
• key exchange
• replay-hardening beyond local duplicate suppression
• fully specified secure ACK behavior

Likely future areas include:

• trusted-neighbor validation
• per-transport security policy
• constrained-profile secure frames
• bridge-assisted security for limited radios