identity-signature-key

Specimen 10 of 96 · Audit-default ordinary rules

Severity: medium
Confidence: high
Maturity: experimental
Selection: Audit default
Policy intent: not required
Release: v0.1.1
Engine facts used: resolved-calls constants successful-signature-calls

Selection and scope#

Selected by the default audit profile, so an ordinary scan runs it.

Shell

./.nightshade/node_modules/.bin/nightshade ./contracts --detectors identity-signature-key
./.nightshade/node_modules/.bin/nightshade detector show identity-signature-key

The first command runs only this rule; --detectors takes a comma-separated list. The second prints the rule's metadata from your installed version.

Severity is review priority. It does not express exploitability or impact. Confidence is detector metadata, not a probability. All built-in rules are experimental.

Compiler scope: the engine supports the pinned profiles 0.28.0, 0.29.0, 0.30.0, 0.31.1, 0.33.0-rc.2, 0.34.0, 0.35.0-rc.1 and 0.35.0, with ZKIR2 by default. Support for this rule can be narrower; the rule documentation below states any narrower scope.

Corpus checks#

Synthetic corpus checks for this rule in the 0.1.1 proof run. A check counts only with compiler acceptance and complete analysis.

Positive detected	Corrected quiet	Lookalike quiet	Other negative quiet	Incomplete
1/4	4/4	4/4	0/0	0

Deviations recorded for this rule:

Case	Kind	Expected to observed lines	Issue
synthetic-regressions.json / identity-signature-key-71	positive	[6] to []	miss, exact expectation mismatch
synthetic-regressions.json / identity-signature-key-71	lookalike	[7] to []	exact expectation mismatch
synthetic-regressions.json / identity-signature-key-96	positive	[4,7] to []	miss, exact expectation mismatch
synthetic-regressions.json / identity-signature-key-96	lookalike	[5,9] to []	exact expectation mismatch
synthetic-regressions.json / identity-signature-key-97	positive	[10,13] to []	miss, exact expectation mismatch
synthetic-regressions.json / identity-signature-key-97	lookalike	[11,15] to []	exact expectation mismatch

These are behavior checks on synthetic fixtures, not a precision or recall estimate. See evaluation.

Rule documentation#

From docs/detectors/identity-signature-key.md at v0.1.1.

Availability: default-on; severity medium, confidence high. No application policy is needed. This rule reports only a statically known identity key on a modeled successful history, not every unconstrained verification key.

Example and scenario#

Compact

assert(jubjubSchnorrVerify<1>(message, signature, default<JubjubPoint>), "signature");
round.increment(1);

An identity verification key does not supply the intended signer authentication. The known-key diagnosis is factual; the analyzer does not construct a signature, prove exploitability, or infer a deployed application's intended signer.

Recommendation#

Reject the identity key and bind the verification key to the intended trusted signer. A nonidentity check alone does not establish trusted ownership or complete key validity. The pinned stable 0.35.0 and 0.35.0-rc.1 standard-library verifiers reject identity keys internally; profile support is a ZKIR2 subset, and upgrades need compatibility review.

Evidence and known false positives#

Canonical resolved stdlib calls retain separate key operands on successful histories. Aliases, helpers, known zero multiplication and caller equality refinements are supported. Rejected histories and same-named application circuits are quiet. No new observation is enabled in projects without the canonical verifier. Observation exhaustion remains explicitly incomplete.

Suppress a match#

If a match is intentional, suppress it on the line before with the exact rule ID and a reason of at least eight characters: