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

# Shielded space

Private payments on Mazze, proven with post-quantum STARKs, with no trusted setup.

The shielded space is Mazze's third space. It holds value as private **notes**. A shielded transaction spends notes and creates new ones, and a zero-knowledge proof shows the spend is valid without revealing the owners or the amounts.

{% hint style="warning" %}
**Status.** The shielded space is implemented on the `shielded-space` branch and runs end to end on a local devnet: shield-in, a private payment, shield-out, backing equal to the sum of the notes, burned fees, refused double-spends. On public networks the lane stays **inactive** until an activation height is set.
{% endhint %}

<figure><picture><source srcset="/files/ZeOtPK4izMOnh9WDQe1H" media="(prefers-color-scheme: dark)"><img src="https://1357981310-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FmAeIGZKbaFvqhD69HxCH%2Fuploads%2Fgit-blob-d926ecfc0a0f622a3dc3165e3e625005cd6668c0%2Fdiagram-shielded-flow.svg?alt=media" alt="Value flow: shield-in from a native account to the bridge, private payment and claim inside the shielded space, shield-out to a public address"></picture><figcaption></figcaption></figure>

## Why it is built this way

| Goal                          | How the shielded space gets there                                                                                                                       |
| ----------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Privacy that lasts**        | Note commitments are statistically hiding. What a note contains cannot be revealed later, by any amount of computing power, quantum computers included. |
| **No trusted setup**          | Proofs are STARKs: transparent, hash-based, with no setup ceremony and no trapdoor that could mint coins.                                               |
| **Post-quantum soundness**    | Security rests on hash functions (Poseidon2, Keccak-256, SHAKE256), not on elliptic curves or pairings.                                                 |
| **Nothing to tell apart**     | Every transaction spends two notes and creates two, carries a recovery slot and pays the same constant fee. Shield-in, payment and claim look alike.    |
| **A node that knows nothing** | The node never sees a key, a note opening or a Merkle path. Wallets prove locally and rebuild the tree from public data.                                |
| **Recovery from a seed**      | Change and claimed notes can be rebuilt from the 32-byte seed alone.                                                                                    |
| **Supply you can check**      | All shielded value sits in one native balance, the backing. The backing always equals the sum of the notes.                                             |

## Pages

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>Design</strong></td><td>The threat model, what is public, and the two-stage pipeline.</td><td><a href="/shielded-space/overview.md">Design</a></td></tr><tr><td><strong>Notes, keys and nullifiers</strong></td><td>The commitment, the spend keys, and how double spends are stopped.</td><td><a href="/shielded-space/notes-and-keys.md">Notes, keys and nullifiers</a></td></tr><tr><td><strong>Proof system PS-1</strong></td><td>The 2×2 spend statement and the STARK that proves it.</td><td><a href="/shielded-space/proof-system.md">Proof system PS-1</a></td></tr><tr><td><strong>The shielded lane</strong></td><td>Block sections, slots, fees, verification and execution.</td><td><a href="/shielded-space/shielded-lane.md">The shielded lane</a></td></tr><tr><td><strong>Wallet guide</strong></td><td>Shield in, pay, receive, claim, shield out and restore.</td><td><a href="/shielded-space/wallet.md">Wallet guide</a></td></tr><tr><td><strong>Shielded RPC</strong></td><td>The four <code>shielded_*</code> methods and what they return.</td><td><a href="/shielded-space/rpc.md">Shielded RPC</a></td></tr></tbody></table>

## Legacy pool

Before the shielded space, Mazze shipped a Groth16 shielded pool as an internal contract in the native space. It is still in the code base. Its documentation is under [Legacy pool (Groth16)](/shielded-space/legacy-pool.md).