> ## Documentation Index
> Fetch the complete documentation index at: https://litprotocol-feat-rusk-sdk.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# PKP Sign

> Use your PKP to sign a message with the selected chain and scheme. The signing operation will automatically find the most optimised price, or you can specify a custom maximum price using the userMaxPrice parameter.

<Tip>
  See the [PKP Sign Reference API](/sdk/sdk-reference/lit-client/functions/createLitClient#chain-raw-pkpsign) for more details on how to sign a message with your PKP.
</Tip>

# Prerequisites

<Note>
  * `authContext` is required. This is the result from the authentication flow.
  * `pubkey` is required. This is the public key of the PKP to sign with.
</Note>

# Quick Example

```ts theme={null}
// The message string will be UTF-8 encoded before signing.
// Hashing (e.g., Keccak256 for Ethereum, SHA256 for Bitcoin)
// is handled automatically by the Lit Protocol based on the selected chain.
const messageBytes = new TextEncoder().encode(messageToSign);

const signatures = await litClient.chain.raw.pkpSign({
  chain: "ethereum",
  signingScheme: "EcdsaK256Sha256",
  pubKey: pkpInfo.pubkey,
  authContext: authContext,
  toSign: messageBytes, // UTF-8 encoded message
});
```

### Hashing defaults and bypass

By default the SDK hashes ECDSA payloads for you using the canonical function for each chain (Ethereum → keccak256, Bitcoin/Cosmos → SHA-256/SHA-384) before sending to the nodes for signing. Schnorr/EdDSA schemes receive the raw bytes exactly as you provided them. If you already computed a digest (for example when signing EIP-712 typed data) you can pass it directly and opt out of the SDK hashing step by setting `bypassAutoHashing: true`:

```ts theme={null}
const digestBytes = hexToBytes(hashTypedData(typedData));

const signature = await litClient.chain.raw.pkpSign({
  chain: 'ethereum',
  signingScheme: 'EcdsaK256Sha256',
  pubKey: pkpInfo.pubkey,
  authContext,
  toSign: digestBytes,
  bypassAutoHashing: true,
});
```

***

# Available signing schemes

### ECDSA Schemes

| Scheme            | Curve      |
| ----------------- | ---------- |
| `EcdsaK256Sha256` | secp256k1  |
| `EcdsaP256Sha256` | NIST P‑256 |
| `EcdsaP384Sha384` | NIST P‑384 |

### EdDSA Schemes

| Scheme                 | Curve   |
| ---------------------- | ------- |
| `SchnorrEd25519Sha512` | ed25519 |
| `SchnorrEd448Shake256` | ed448   |

### Schnorr Variants

| Scheme               | Curve      |
| -------------------- | ---------- |
| `SchnorrK256Taproot` | secp256k1  |
| `SchnorrK256Sha256`  | secp256k1  |
| `SchnorrP256Sha256`  | NIST P‑256 |
| `SchnorrP384Sha384`  | NIST P‑384 |

### ZK/Privacy Schnorr Variants

| Scheme                         | Curve          |
| ------------------------------ | -------------- |
| `SchnorrRistretto25519Sha512`  | Ristretto25519 |
| `SchnorrRedJubjubBlake2b512`   | Jubjub         |
| `SchnorrRedDecaf377Blake2b512` | Decaf377       |
| `SchnorrkelSubstrate`          | sr25519        |