How Verification Works

How RunProof Verification Works

RunProof verification ensures that an AI agent’s execution record has not been tampered with.

Substr8 verification checks three things:

  1. The execution trace was not modified
  2. The trace represents exactly the events that occurred
  3. The proof was created by the expected agent

Step 1 — Hash Chain Integrity

Each event in a RunProof includes a hash of the previous event.

event_1 → hash
event_2 → hash(event_1)
event_3 → hash(event_2)

If any event changes, the chain breaks.

How it works:

event_1_hash = sha256(event_1)
event_2_hash = sha256(event_2 + event_1_hash)
event_3_hash = sha256(event_3 + event_2_hash)

Verification recomputes this chain and confirms it matches the stored values.

Result:

✓ Hash chain integrity verified

Step 2 — Merkle Root Commitment

The Merkle root is a single cryptographic commitment to all events in the trace.

event_1_hash    event_2_hash    event_3_hash    event_4_hash
      \            /                  \            /
       \          /                    \          /
        hash_1_2                        hash_3_4
              \                           /
               \                         /
                \                       /
                 \                     /
                      Merkle Root

Verification recomputes the Merkle tree and checks:

computed_root == stored_root

Result:

✓ Merkle root commitment verified

Step 3 — Ed25519 Signature

This confirms who created the proof.

The RunProof’s Merkle root is signed using Ed25519.

Verification checks:

verify(signature, merkle_root, public_key) → true

Result:

✓ Ed25519 signature verified

Final Result

If all three checks succeed:

RunProof: VALID ✓

CLI output:

substr8 proof verify runproof.json
╭──────────────────────────── Verification Result ─────────────────────────────╮
│ ✓ RunProof: VALID                                                            │
╰──────────────────────────────────────────────────────────────────────────────╯

Checks:
  ✓ hash_chain      — Event order verified
  ✓ merkle_root     — Event set verified
  ✓ signature       — Proof origin verified

Why These Checks Matter

CheckProtectsPrevents
Hash chainEvent orderReordering or modifying events
Merkle rootEvent setAdding or removing events
SignatureOriginForging proofs

Together these guarantees mean:

  • Events cannot be reordered or modified
  • The event set cannot be changed without detection
  • The proof can be traced to its origin

This makes RunProof a portable, tamper-evident record of agent execution.

Quick Reference

Hash chain   → protects event order
Merkle root  → protects event set
Signature    → proves origin

Try It

# Install
pip install substr8
 
# Verify any RunProof
substr8 proof verify runproof.json

Next Steps

RunProofSpecification