> ## Documentation Index
> Fetch the complete documentation index at: https://sdk.umbraprivacy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ZK Prover Interfaces

> Six injectable Groth16 prover interfaces (one per Circom circuit). Each implements prove(inputs) returning {proofA, proofB, proofC}. Provers ship in @umbra-privacy/sdk/zk-prover.

## Overview

Every operation that generates a [Groth16](/sdk/advanced/cryptography/groth16) ZK proof requires a prover passed through `deps`. **There is no built-in default** — you must always supply one. All provers follow the same `prove(inputs) → { proofA, proofB, proofC }` contract.

In V18 the prover and the asset CDN live inside the main SDK at the `@umbra-privacy/sdk/zk-prover` subpath. The standalone `@umbra-privacy/web-zk-prover` package from V13 has been deleted.

For instantiation, Web Worker setup, and remote proving backends, see [ZK Provers](/sdk/advanced/zk-provers).

<Note>
  The **burner** prover factory and interface names retained their V13 spellings (`getClaim…`, `IZkProverForClaim…`). The **creator** prover factories were renamed — ETA-source: `getETAIntoStealthPoolNoteCreatorProver` / `IZkProverForETAIntoStealthPoolNote`; ATA-source: `getATAIntoStealthPoolNoteCreatorProver` / `IZkProverForATAIntoStealthPoolNote`. The high-level **factory functions** in `/deposit`, `/withdrawal`, `/burn` also use the new vocabulary. Both creator and burner prover names coexist but follow different patterns.
</Note>

***

## `IZkProverForUserRegistration`

```typescript theme={null}
interface IZkProverForUserRegistration {
  prove(inputs: UserRegistrationCircuitInputs): Promise<{
    proofA: Groth16ProofA;
    proofB: Groth16ProofB;
    proofC: Groth16ProofC;
  }>;
}
```

Required by: `getUserRegistrationFunction` deps (`zkProver`).

***

## `IZkProverForETAIntoStealthPoolNote`

```typescript theme={null}
interface IZkProverForETAIntoStealthPoolNote {
  prove(inputs: ETAIntoStealthPoolNoteCircuitInputs): Promise<{
    proofA: Groth16ProofA;
    proofB: Groth16ProofB;
    proofC: Groth16ProofC;
  }>;
}
```

**Shared by both ETA-source creator variants** — `getETAIntoSelfBurnableStealthPoolNoteCreatorFunction` and `getETAIntoReceiverBurnableStealthPoolNoteCreatorFunction` both take a `zkProver: IZkProverForETAIntoStealthPoolNote` dep. Use `getETAIntoStealthPoolNoteCreatorProver()` to get a default instance.

For ATA-source creation, see `IZkProverForATAIntoStealthPoolNote` below.

***

## `IZkProverForClaimSelfClaimableUtxoIntoEncryptedBalance`

```typescript theme={null}
interface IZkProverForClaimSelfClaimableUtxoIntoEncryptedBalance {
  readonly maxUtxoCapacity: 1;
  prove(inputs: ClaimSelfClaimableUtxoIntoEncryptedBalanceCircuitInputs): Promise<{
    proofA: Groth16ProofA;
    proofB: Groth16ProofB;
    proofC: Groth16ProofC;
  }>;
}
```

Required by: `getSelfBurnableStealthPoolNoteIntoETABurnerFunction` deps (`zkProver`). `maxUtxoCapacity: 1` — one note per proof, the SDK loops internally if you submit an array.

***

## `IZkProverForClaimReceiverClaimableUtxoIntoEncryptedBalance`

```typescript theme={null}
interface IZkProverForClaimReceiverClaimableUtxoIntoEncryptedBalance {
  prove(
    inputs: ClaimReceiverClaimableUtxoIntoEncryptedBalanceCircuitInputs,
    nLeaves: ClaimBatchSize,
  ): Promise<{
    proofA: Groth16ProofA;
    proofB: Groth16ProofB;
    proofC: Groth16ProofC;
  }>;
}
```

Required by: `getReceiverBurnableStealthPoolNoteIntoETABurnerFunction` deps (`zkProver`). This prover accepts a batch size `nLeaves` (1–5 in V18 — the SDK chunks to 5 notes per proof).

***

## `IZkProverForClaimSelfClaimableUtxoIntoPublicBalance`

```typescript theme={null}
interface IZkProverForClaimSelfClaimableUtxoIntoPublicBalance {
  readonly maxUtxoCapacity: 1;
  prove(inputs: ClaimSelfClaimableUtxoIntoPublicBalanceCircuitInputs): Promise<{
    proofA: Groth16ProofA;
    proofB: Groth16ProofB;
    proofC: Groth16ProofC;
  }>;
}
```

Required by: `getSelfBurnableStealthPoolNoteIntoATABurnerFunction` deps (`zkProver`).

***

## `IZkProverForATAIntoStealthPoolNote`

```typescript theme={null}
interface IZkProverForATAIntoStealthPoolNote {
  prove(inputs: ATAIntoStealthPoolNoteCircuitInputs): Promise<{
    proofA: Groth16ProofA;
    proofB: Groth16ProofB;
    proofC: Groth16ProofC;
  }>;
}
```

**Shared by both ATA-source creator variants** — `getATAIntoSelfBurnableStealthPoolNoteCreatorFunction` and `getATAIntoReceiverBurnableStealthPoolNoteCreatorFunction` both take a `zkProver: IZkProverForATAIntoStealthPoolNote` dep. Use `getATAIntoStealthPoolNoteCreatorProver()` to get a default instance.

***

## Quick Setup

Per-circuit factories are exported from `@umbra-privacy/sdk/zk-prover`. They wrap [snarkjs](https://github.com/iden3/snarkjs) Groth16 and fetch proving keys from Umbra's CDN by default.

```typescript theme={null}
import {
  getUserRegistrationProver,
  getETAIntoStealthPoolNoteCreatorProver,
  getATAIntoStealthPoolNoteCreatorProver,
  getClaimSelfClaimableUtxoIntoEncryptedBalanceProver,
  getClaimReceiverClaimableUtxoIntoEncryptedBalanceProver,
  getClaimSelfClaimableUtxoIntoPublicBalanceProver,
} from "@umbra-privacy/sdk/zk-prover";

const registrationProver = getUserRegistrationProver();

// Stealth Pool Note creators — one prover instance is shared across self/receiver variants of the same source
const createFromEtaProver  = getETAIntoStealthPoolNoteCreatorProver();  // both ETA self-burnable + receiver-burnable
const createFromPataProver = getATAIntoStealthPoolNoteCreatorProver();  // both ATA self-burnable + receiver-burnable

// Burners
const burnSelfIntoEtaProver     = getClaimSelfClaimableUtxoIntoEncryptedBalanceProver();
const burnReceiverIntoEtaProver = getClaimReceiverClaimableUtxoIntoEncryptedBalanceProver();
const burnSelfIntoPataProver    = getClaimSelfClaimableUtxoIntoPublicBalanceProver();
```

Each factory accepts an optional `IZkAssetProvider` argument — a simple interface with one method, `getAssetUrls(type, variant?)`. When no provider is passed, the factories default to the CDN provider (equivalent to calling `getCdnZkAssetProvider()` from `@umbra-privacy/sdk/zk-prover/cdn`), which fetches proving keys from Umbra's CDN. You can supply your own provider to customise asset resolution.

See [ZK Provers](/sdk/advanced/zk-provers) for Web Worker setup, custom asset providers, and remote proving backends.