> For the complete documentation index, see [llms.txt](https://plabs.gitbook.io/plabs-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://plabs.gitbook.io/plabs-docs/privacy-core/state-machine.md).

# Note state machine (OrchardVerifier)

`OrchardVerifier` is the **on-chain state machine** for Privacy Core. All applications (pERC20, pSWAP, …) share this execution semantics.

## Scope

```
OrchardVerifier DOES:              DOES NOT:
✓ Groth16 verification             ✗ ERC-20 metadata
✓ Merkle append                    ✗ totalSupply accounting
✓ nullifier anti double-spend      ✗ external ERC-20/ETH custody
✓ binding + spendAuth sigs         ✗ swap / HTLC logic
✓ frozenRoot binding
```

Each pool instance has its **own** tree, nullifier set, verifier ref, and `cmxFrozenRoot`.\
**Asset identity = contract address** (same bytecode on different chains = different state).

## State

| State                 | Description                                |
| --------------------- | ------------------------------------------ |
| `_tree`               | depth-32 Poseidon incremental Merkle tree  |
| `_isSpent[nf]`        | Spent nullifiers                           |
| `cmxExists[cmx]`      | Inserted commitments (no duplicate leaves) |
| `_allRootsEver[root]` | Permanent historical roots                 |
| `_frozenRoot`         | Compliance IMT root                        |
| `groth16Verifier`     | Groth16 verifier reference                 |
| `admin`               | Compliance / config authority              |

## Bundle execution order

```
1. For each BundleAction:
   a. pubFields[8] canonicality (< Fr)
   b. pubFields ↔ calldata equality
   c. Groth16 verifyAction
   d. spendAuthSig verify
2. bindingSig verify (before state writes)
3. For each action:
   a. mark nfOld spent
   b. insert cmx (reject zero / duplicate)
   c. emit NoteAdded / NoteConfirmed
```

**Invariant**: no public `bundle()` entrypoint — only app-layer `mint`/`burn`/`transfer` call `_executeBundle` (audit C-1).

## Views

| Method                | Meaning             |
| --------------------- | ------------------- |
| `cmxRoot()`           | Latest tree root    |
| `isValidAnchor(root)` | Root was ever valid |
| `isSpent(nf)`         | Nullifier spent     |
| `treeSize()`          | Commitment count    |

## Next

* [Groth16 action circuit](/plabs-docs/privacy-core/groth16-action-circuit.md)
* [Universal call format](/plabs-docs/privacy-core/universal-call-format.md)


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