{"alg":"ed25519","key_id":"dsc3-c178db1aad58b510","note":"If public_key_b64 is null, the engine has no signing key configured (set ENGINE_SIGNING_KEY env var or provision /etc/isomorphic-engine/keys/signing.key). Tier 1 (input_hash + spins_hash + partner-side energy recompute) still works without a key.","public_key_b64":"1PCFFxCr6XTundCxeYiGyQKST9273Jh4F9U5ZUzIobM=","verification_recipe":["1. Decode public_key_b64 → 32 bytes Ed25519 verifying key.","2. From a solve response: take the `verification` block, REMOVE the `signature` and `bsv_anchor` fields, JSON-serialize what remains.","3. base64-decode `signature.signature` → 64 bytes Ed25519 signature.","4. Verify signature(payload, public_key). If valid, the result was produced by THIS engine instance.","5. Independently recompute energy from `best_spins` (or decompressed `best_spins_b64`) and the input matrix (regenerate from `seed` if server-generated). If energy matches `best_energy`, the work is mathematically real."]}