@scure/starknet
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Audited & minimal implementation of Starknet cryptography including Pedersen and Stark Curve
372 lines • 16.2 kB
TypeScript
/*! scure-starknet - MIT License (c) 2022 Paul Miller (paulmillr.com) */
import { type IField } from '@noble/curves/abstract/modular.js';
import { poseidon } from '@noble/curves/abstract/poseidon.js';
import { type ECDSASignature, type ECDSASignatureCons, type ECDSASignatureFormat, type ECDSASignOpts, type WeierstrassPoint, type WeierstrassPointCons } from '@noble/curves/abstract/weierstrass.js';
import { type TArg, type TRet } from '@noble/hashes/utils.js';
type Hex = Uint8Array | string;
type PrivKey = Hex | bigint;
type SignOpts = Omit<ECDSASignOpts, 'prehash'> & {
prehash?: false;
};
type VerifyOpts = {
format?: ECDSASignatureFormat;
};
/** Upper bound for Stark message hashes and `Signature.r` values. */
export declare const MAX_VALUE: bigint;
/**
* Stark-friendly short Weierstrass point constructor.
* @example
* Reach for the curve point constructor when you need low-level Stark curve math.
* ```ts
* Point.BASE.toBytes(true);
* ```
*/
declare const Point: WeierstrassPointCons<bigint>;
/**
* Normalizes a Stark private key into a 32-byte lowercase hex string without `0x`.
* @param privKey - private key as bytes or hex
* @returns Zero-padded private key hex.
* Assumes `privKey` encodes at most 32 bytes.
* Longer inputs are preserved here and rejected later by curve operations.
* @example
* Normalize a short hex string into the canonical 32-byte Stark private key form.
* ```ts
* normalizePrivateKey('1');
* ```
*/
export declare function normalizePrivateKey(privKey: TArg<Hex>): string;
/**
* Derives a Stark public key from a private key.
* @param privKey - private key as bytes or hex
* @param isCompressed - whether to return the compressed public key format
* @returns Encoded Stark public key bytes.
* @example
* Derive the Stark public key from a private key.
* ```ts
* getPublicKey('1');
* ```
*/
export declare function getPublicKey(privKey: TArg<Hex>, isCompressed?: boolean): TRet<Uint8Array>;
/**
* Computes the Stark ECDH shared secret for a private key and peer public key.
* @param privKeyA - local private key as bytes or hex
* @param pubKeyB - peer public key as bytes or hex
* @returns Compressed shared point bytes.
* Intentional API-compatibility behavior for existing callers.
* This mirrors noble-curves' ECDH helper and returns the compressed shared curve
* point, not the SEC 1 raw x-coordinate or KDF input.
* @example
* Compute the shared secret from one private key and the peer public key.
* ```ts
* import { getPublicKey, getSharedSecret } from '@scure/starknet';
* getSharedSecret('1', getPublicKey('2'));
* ```
*/
export declare function getSharedSecret(privKeyA: TArg<Hex>, pubKeyB: TArg<Hex>): TRet<Uint8Array>;
/**
* Signs a Stark message hash without prehashing it first.
* @param msgHash - message hash inside the Stark field range
* @param privKey - private key as bytes or hex
* @param opts - Optional ECDSA signing overrides. See {@link SignOpts}; `prehash: true` is not exposed because this wrapper signs a prehashed Stark message. Explicit `format` values are accepted and decoded back into the returned `Signature`.
* @returns Parsed Stark ECDSA signature.
* If `opts.format` is `'recovered'`, the returned `Signature` preserves the recovery bit.
* @throws On unsupported `opts.prehash` overrides. {@link TypeError}
* @throws On Stark message hashes or signature values outside the Stark field range. {@link RangeError}
* @example
* Sign a prehashed Stark message with a private key.
* ```ts
* sign('1', '2');
* ```
*/
export declare function sign(msgHash: TArg<Hex>, privKey: TArg<Hex>, opts?: TArg<SignOpts>): ECDSASignature;
/**
* Verifies a Stark signature against a message hash and public key.
* @param signature - signature object or encoded signature bytes/hex
* @param msgHash - message hash inside the Stark field range
* @param pubKey - public key as bytes or hex
* @param opts - Optional byte-signature decode options. See {@link VerifyOpts}; pass `format` to bypass legacy DER-first fallback and decode compact, recovered, or DER explicitly.
* @returns Whether the signature is valid for the message hash.
* @throws On Stark message hashes or signature values outside the Stark field range. {@link RangeError}
* @example
* Verify a Stark signature against the message hash and public key.
* ```ts
* import { getPublicKey, sign, verify } from '@scure/starknet';
* const msgHash = '1';
* const privKey = '2';
* verify(sign(msgHash, privKey), msgHash, getPublicKey(privKey));
* ```
*/
export declare function verify(signature: TArg<ECDSASignature | Hex>, msgHash: TArg<Hex>, pubKey: TArg<Hex>, opts?: VerifyOpts): boolean;
/**
* Stark ECDSA signature constructor and byte decoders.
* Direct alias of noble's signature class: validates `r`/`s` and supports compact, DER, and
* recovered encodings.
* @example
* Construct a Stark signature object and serialize it back to hex.
* ```ts
* new Signature(1n, 2n).toHex();
* ```
*/
declare const Signature: ECDSASignatureCons;
/**
* Helper methods for Stark private keys and point precomputation.
* Private-key helpers treat string/Uint8Array inputs as raw secret-key bytes; `precompute()`
* mutates and returns the supplied point.
* @example
* Check whether a candidate private key lies in the Stark scalar field.
* ```ts
* utils.isValidPrivateKey('01');
* ```
*/
declare const utils: {
normPrivateKeyToScalar: (key: TArg<PrivKey>) => bigint;
isValidPrivateKey(privateKey: PrivKey): boolean;
randomPrivateKey: () => Uint8Array;
precompute: (windowSize?: number, point?: WeierstrassPoint<bigint>) => WeierstrassPoint<bigint>;
};
export { Point, Signature, utils };
/**
* Derives a Stark private key from arbitrary seed material with rejection sampling.
* @param seed - seed bytes or hex
* @returns Hex private key suitable for Stark signatures.
* Returns lowercase hex without `0x` or left padding; callers that need the canonical 32-byte form
* should normalize it separately.
* @throws If rejection sampling does not find a valid Stark private key within the retry limit. {@link Error}
* @example
* Grind arbitrary seed material into a Stark private key.
* ```ts
* grindKey('01');
* ```
*/
export declare function grindKey(seed: TArg<Hex>): string;
/**
* Derives the Stark key x-coordinate for a private key.
* @param privateKey - private key as bytes or hex
* @returns Stark key hex string with `0x` prefix.
* Returns only the canonical unpadded x-coordinate string, not the SEC 1 compressed point bytes.
* @example
* Extract the Stark public key x-coordinate as a hex string.
* ```ts
* getStarkKey('1');
* ```
*/
export declare function getStarkKey(privateKey: TArg<Hex>): string;
/**
* Turns a 65-byte Ethereum signature into a Stark private key.
* @param signature - Ethereum signature hex with `0x` prefix
* @returns Stark private key hex.
* Uses the signature's 32-byte `r` component as the grinding seed.
* @throws If grinding the Ethereum signature fails to produce a Stark private key within the retry limit. {@link Error}
* @throws On wrong Ethereum signature type. {@link TypeError}
* @throws On wrong Ethereum signature length. {@link RangeError}
* @example
* Convert an Ethereum signature into deterministic Stark key material.
* ```ts
* ethSigToPrivate(
* '0x21fbf0696d5e0aa2ef41a2b4ffb623bcaf070461d61cf7251c74161f82fec3a43' +
* '70854bc0a34b3ab487c1bc021cd318c734c51ae29374f2beb0e6f2dd49b4bf41c'
* );
* ```
*/
export declare function ethSigToPrivate(signature: string): string;
/**
* Builds the StarkEx account derivation path for a layer, application, address, and index.
* @param layer - StarkEx layer name
* @param application - StarkEx application name
* @param ethereumAddress - Ethereum address used in derivation
* @param index - Final unhardened BIP32 child index inside the derived subtree; should be an integer in `[0, 2^31)`.
* @returns BIP32 derivation path string.
* @throws On wrong index types. {@link TypeError}
* @throws On invalid index ranges or values. {@link RangeError}
* @example
* Derive the StarkEx account path for one wallet and account index.
* ```ts
* getAccountPath('starkex', 'starkdeployement', '0x1', 0);
* ```
*/
export declare function getAccountPath(layer: string, application: string, ethereumAddress: string, index: number): string;
type PedersenArg = Hex | bigint | number;
/**
* Computes the Starknet Pedersen hash of two field elements.
* @param x - first field element as bytes, hex, bigint, or safe integer
* @param y - second field element as bytes, hex, bigint, or safe integer
* @returns Pedersen hash as `0x`-prefixed hex.
* Returns the canonical unpadded x-coordinate string of the final Pedersen point, not a full point
* encoding.
* @throws If Pedersen point encoding fails unexpectedly. {@link Error}
* @throws On Pedersen inputs outside the Stark field range. {@link RangeError}
* @example
* Compute the Pedersen hash of two Stark field elements.
* ```ts
* pedersen(1, 2);
* ```
*/
export declare function pedersen(x: TArg<PedersenArg>, y: TArg<PedersenArg>): string;
/**
* Hashes a list of elements with Pedersen while preserving input order and appending the length.
* @param data - elements to hash
* @param fn - Pairwise fold function, called as `fn(acc, next)` for each
* element and once more with `data.length`.
* @returns Folded hash result.
* @example
* Hash an ordered list of elements with the Starknet Pedersen fold.
* ```ts
* computeHashOnElements([1, 2, 3]);
* ```
*/
export declare const computeHashOnElements: (data: TArg<PedersenArg[]>, fn?: typeof pedersen) => TRet<PedersenArg>;
/**
* Computes Starknet keccak by truncating Keccak-256 to 250 bits.
* @param data - bytes to hash
* @returns Hash as a bigint field element.
* Keeps the low 250 bits of the Keccak-256 digest; it does not right-shift or reduce modulo
* the Stark field.
* @example
* Compute Starknet keccak for raw bytes.
* ```ts
* keccak(new Uint8Array([1, 2, 3]));
* ```
*/
export declare const keccak: (data: TArg<Uint8Array>) => bigint;
/**
* Prime field used by Starknet Poseidon: `2^251 + 17 * 2^192 + 1`.
* Despite the name, canonical encodings still occupy 32 big-endian bytes because `p > 2^251`.
* @example
* Construct one field element in the Starknet Poseidon field.
* ```ts
* Fp251.create(1n);
* ```
*/
export declare const Fp251: Readonly<IField<bigint> & Required<Pick<IField<bigint>, 'isOdd'>>>;
export declare function _poseidonMDS(Fp: IField<bigint>, name: string, m: number, attempt?: number): bigint[][];
/** Poseidon permutation configuration. */
export type PoseidonOpts = {
/** Prime field used by the permutation. */
Fp: IField<bigint>;
/** Number of message elements absorbed per permutation. */
rate: number;
/** Number of capacity elements reserved for domain separation. */
capacity: number;
/** Count of full rounds with a nonlinear layer on every lane; must be even so Poseidon can
* split them around the partial rounds. */
roundsFull: number;
/** Count of partial rounds with a nonlinear layer on one lane. */
roundsPartial: number;
};
/** Poseidon permutation instance returned by the Starknet helpers. */
export type PoseidonFn = ReturnType<typeof poseidon> & {
/** Total permutation width (`rate + capacity`). */
m: number;
/** Number of message elements absorbed per permutation. */
rate: number;
/** Number of capacity elements reserved for domain separation. */
capacity: number;
};
/**
* Creates a Poseidon permutation from explicit parameters and an MDS matrix.
* @param opts - Poseidon permutation parameters. See {@link PoseidonOpts}.
* @param mds - MDS matrix used by the permutation
* @returns Poseidon permutation with Starknet metadata.
* @throws On wrong Poseidon option types. {@link TypeError}
* @throws On invalid Poseidon option ranges. {@link RangeError}
* @example
* Create a Poseidon permutation from explicit parameters and an MDS matrix.
* ```ts
* import { Fp251, poseidonBasic } from '@scure/starknet';
* poseidonBasic(
* { Fp: Fp251, rate: 2, capacity: 1, roundsFull: 8, roundsPartial: 83 },
* [
* [3n, 1n, 1n],
* [1n, -1n, 1n],
* [1n, 1n, -2n],
* ]
* );
* ```
*/
export declare function poseidonBasic(opts: PoseidonOpts, mds: bigint[][]): PoseidonFn;
/**
* Creates a Starknet-compatible Poseidon permutation from parameters and an MDS attempt index.
* @param opts - Poseidon permutation parameters. See {@link PoseidonOpts}.
* @param mdsAttempt - attempt index used to derive the MDS matrix
* @returns Poseidon permutation with Starknet metadata.
* @throws If the derived Poseidon MDS matrix is invalid. {@link Error}
* @throws On wrong Poseidon option or attempt types. {@link TypeError}
* @throws On invalid Poseidon option or attempt ranges. {@link RangeError}
* @example
* Create the default Starknet-compatible Poseidon permutation from parameters alone.
* ```ts
* import { Fp251, poseidonCreate } from '@scure/starknet';
* poseidonCreate({ Fp: Fp251, rate: 2, capacity: 1, roundsFull: 8, roundsPartial: 83 });
* ```
*/
export declare function poseidonCreate(opts: PoseidonOpts, mdsAttempt?: number): PoseidonFn;
/**
* Default Starknet Poseidon permutation.
* Uses the fixed width-3 vector-backed MDS matrix, not the generated `HadesMDS` path from {@link poseidonCreate}.
* @param values - Poseidon state vector to permute.
* @returns Permuted Poseidon state vector.
* @example
* Feed the default Starknet permutation into the standard 2-input hash helper.
* ```ts
* import { poseidonHash, poseidonSmall } from '@scure/starknet';
* poseidonHash(1n, 2n, poseidonSmall);
* ```
*/
export declare const poseidonSmall: PoseidonFn;
/**
* Hashes two field elements with the default Starknet Poseidon permutation.
* Applies the 2-input Starknet padding/domain-separation rule `fn([x, y, 2n])[0]`.
* @param x - first field element
* @param y - second field element
* @param fn - Poseidon permutation to use
* @returns Poseidon hash result.
* @example
* Hash two field elements with Starknet Poseidon.
* ```ts
* poseidonHash(1n, 2n);
* ```
*/
export declare function poseidonHash(x: bigint, y: bigint, fn?: PoseidonFn): bigint;
/**
* Hashes two byte arrays with Poseidon and returns the encoded bytes.
* Interprets inputs as unsigned big-endian integers and returns a minimal big-endian byte string, not a fixed 32-byte field encoding.
* @param x - first byte array
* @param y - second byte array
* @param fn - Poseidon permutation to use
* @returns Poseidon hash encoded as big-endian bytes.
* @example
* Hash two byte arrays and return the Poseidon result as bytes.
* ```ts
* poseidonHashFunc(new Uint8Array([1]), new Uint8Array([2]));
* ```
*/
export declare function poseidonHashFunc(x: TArg<Uint8Array>, y: TArg<Uint8Array>, fn?: PoseidonFn): TRet<Uint8Array>;
/**
* Hashes a single field element with Poseidon.
* Applies the 1-input Starknet padding/domain-separation rule `fn([x, 0n, 1n])[0]`.
* @param x - field element to hash
* @param fn - Poseidon permutation to use
* @returns Poseidon hash result.
* @example
* Hash one field element with Poseidon.
* ```ts
* poseidonHashSingle(1n);
* ```
*/
export declare function poseidonHashSingle(x: bigint, fn?: PoseidonFn): bigint;
/**
* Hashes a list of field elements with Poseidon sponge padding.
* Appends `1n`, zero-pads to a multiple of the permutation rate, then absorbs each rate-sized block into the zero state.
* @param values - field elements to hash
* @param fn - Poseidon permutation to use; custom functions are trusted to return a valid state vector
* @returns Poseidon hash result.
* @throws If internal Poseidon sponge sizing invariants fail unexpectedly. {@link Error}
* @throws On wrong `values` argument types. {@link TypeError}
* @example
* Hash a list of field elements with Poseidon sponge padding.
* ```ts
* poseidonHashMany([1n, 2n, 3n]);
* ```
*/
export declare function poseidonHashMany(values: bigint[], fn?: PoseidonFn): bigint;
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