audit chain and log file integrity

[kckil]

permit0/crates/permit0-cli/src/cmd/serve.rs

Line 609 in 753f283

// Shared in-memory audit sink so /check and /audit/replay both

Looks like this is already a to-do for you, but you may want to consider pulling all of this logic out into a separate handler. Eventually you may want to build in log file integrity to preserve full audit chain accountability (e.g., https://docs.aws.amazon.com/awscloudtrail/latest/userguide/cloudtrail-log-file-validation-intro.html). You may also want this to be easily configurable for durable off-box storage into s3/datadog or similar using a Otel drain.

[arian-gogani]

hash-chaining the audit log is the right approach. a few things from building this exact primitive:

1. canonical serialization before hashing. serde_json output isn't guaranteed to be deterministic across versions or configurations. RFC 8785 (JSON Canonicalization Scheme) ensures the same data always produces the same bytes. without this, hash chains can break across upgrades.

2. Ed25519 signatures per entry. a hash chain proves internal consistency. a signature proves who generated each entry. for audit-grade accountability, both are needed.

3. the action_ref pattern. SHA-256(JCS({agent_id, action_type, scope, timestamp_ms})) gives each log entry a deterministic, content-addressed identifier. the same action always produces the same ref regardless of which implementation computes it.

we built this in an open-source library (Python, with a TS skeleton). the receipt format has been cross-validated across 4 JCS implementations. the hash-linking and Ed25519 signing are exactly what you'd need for log file integrity.

github.com/arian-gogani/nobulex

the permit0 policy enforcement + nobulex tamper-evident receipts would be a strong composition: permit0 prevents unauthorized actions, receipts prove the enforcement decisions were made correctly.