# Security Review

## Findings

### High: assertion authenticity is assumed but not tied to required receiver behavior

The draft correctly says portable trust assertions need authenticated origin and integrity protection, but it does not make rejection behavior explicit. A receiver should not be allowed to consume an unauthenticated portable assertion and still claim conformance.

### High: replay handling depends on freshness, but the minimum stale-data rule is too soft

Freshness is mandatory, which is good, but receivers only SHOULD reject or downgrade stale assertions. For clearly expired assertions, that is too weak. A stronger interoperability floor is warranted.

### Medium: negative trust sharing creates reputational poisoning risk without minimum evidence discipline

The document warns about poisoning and privacy, yet evidence references remain entirely optional. That is reasonable for all assertions, but negative portable assertions may need a stronger requirement for explanation or evidence linkage.

### Medium: collusion risk is identified but not operationalized

The draft notes that multiple issuers may not be independent, but it gives no guidance on how a relying party should avoid double-counting related issuers. Even a brief cautionary requirement or implementation note would help.

## Open questions

- Should unauthenticated portable trust assertions be explicitly non-conformant?
- Should negative assertions require either evidence reference or explanation code?

## Residual risk

Even with improvements, dynamic trust will remain vulnerable to social and operational abuse that pure wire semantics cannot prevent. The draft should state those limits plainly.
