Threat model for detecting Missing Output Datum vulnerabilities.

A Missing Output Datum Attack targets state-machine validators that require a continuation output to carry a valid datum. If the validator does not enforce that requirement, an attacker can remove the datum from the continuation output and still have the transaction validate.

Consequences ==

1. State corruption: The next contract state cannot be reconstructed from the continuation output.
2. Permanent fund locking: Future spends may fail because the validator cannot decode the expected state from a missing datum.

Mitigation ==

A secure validator should explicitly reject continuation outputs without datum (e.g. NoOutputDatum) and ensure stateful outputs always include valid datum.

This threat model mutates a continuation output by replacing its datum with TxOutDatumNone. If the transaction still validates, the script may be vulnerable.