@noble/post-quantum/utils.d.ts

Auditable & minimal JS implementation of post-quantum cryptography: FIPS 203, 204, 205, Falcon

/**
 * Utilities for hex, bytearray and number handling.
 * @module
 */
/*! noble-post-quantum - MIT License (c) 2024 Paul Miller (paulmillr.com) */
import { type CHash, type TypedArray, abytes, concatBytes, randomBytes as randb } from '@noble/hashes/utils.js';
/**
 * Bytes API type helpers for old + new TypeScript.
 *
 * TS 5.6 has `Uint8Array`, while TS 5.9+ made it generic `Uint8Array<ArrayBuffer>`.
 * We can't use specific return type, because TS 5.6 will error.
 * We can't use generic return type, because most TS 5.9 software will expect specific type.
 *
 * Maps typed-array input leaves to broad forms.
 * These are compatibility adapters, not ownership guarantees.
 *
 * - `TArg` keeps byte inputs broad.
 * - `TRet` marks byte outputs for TS 5.6 and TS 5.9+ compatibility.
 */
export type TypedArg<T> = T extends BigInt64Array ? BigInt64Array : T extends BigUint64Array ? BigUint64Array : T extends Float32Array ? Float32Array : T extends Float64Array ? Float64Array : T extends Int16Array ? Int16Array : T extends Int32Array ? Int32Array : T extends Int8Array ? Int8Array : T extends Uint16Array ? Uint16Array : T extends Uint32Array ? Uint32Array : T extends Uint8ClampedArray ? Uint8ClampedArray : T extends Uint8Array ? Uint8Array : never;
/** Maps typed-array output leaves to narrow TS-compatible forms. */
export type TypedRet<T> = T extends BigInt64Array ? ReturnType<typeof BigInt64Array.of> : T extends BigUint64Array ? ReturnType<typeof BigUint64Array.of> : T extends Float32Array ? ReturnType<typeof Float32Array.of> : T extends Float64Array ? ReturnType<typeof Float64Array.of> : T extends Int16Array ? ReturnType<typeof Int16Array.of> : T extends Int32Array ? ReturnType<typeof Int32Array.of> : T extends Int8Array ? ReturnType<typeof Int8Array.of> : T extends Uint16Array ? ReturnType<typeof Uint16Array.of> : T extends Uint32Array ? ReturnType<typeof Uint32Array.of> : T extends Uint8ClampedArray ? ReturnType<typeof Uint8ClampedArray.of> : T extends Uint8Array ? ReturnType<typeof Uint8Array.of> : never;
/** Recursively adapts byte-carrying API input types. See {@link TypedArg}. */
export type TArg<T> = T | ([TypedArg<T>] extends [never] ? T extends (...args: infer A) => infer R ? ((...args: {
    [K in keyof A]: TRet<A[K]>;
}) => TArg<R>) & {
    [K in keyof T]: T[K] extends (...args: any) => any ? T[K] : TArg<T[K]>;
} : T extends [infer A, ...infer R] ? [TArg<A>, ...{
    [K in keyof R]: TArg<R[K]>;
}] : T extends readonly [infer A, ...infer R] ? readonly [TArg<A>, ...{
    [K in keyof R]: TArg<R[K]>;
}] : T extends (infer A)[] ? TArg<A>[] : T extends readonly (infer A)[] ? readonly TArg<A>[] : T extends Promise<infer A> ? Promise<TArg<A>> : T extends object ? {
    [K in keyof T]: TArg<T[K]>;
} : T : TypedArg<T>);
/** Recursively adapts byte-carrying API output types. See {@link TypedArg}. */
export type TRet<T> = T extends unknown ? T & ([TypedRet<T>] extends [never] ? T extends (...args: infer A) => infer R ? ((...args: {
    [K in keyof A]: TArg<A[K]>;
}) => TRet<R>) & {
    [K in keyof T]: T[K] extends (...args: any) => any ? T[K] : TRet<T[K]>;
} : T extends [infer A, ...infer R] ? [TRet<A>, ...{
    [K in keyof R]: TRet<R[K]>;
}] : T extends readonly [infer A, ...infer R] ? readonly [TRet<A>, ...{
    [K in keyof R]: TRet<R[K]>;
}] : T extends (infer A)[] ? TRet<A>[] : T extends readonly (infer A)[] ? readonly TRet<A>[] : T extends Promise<infer A> ? Promise<TRet<A>> : T extends object ? {
    [K in keyof T]: TRet<T[K]>;
} : T : TypedRet<T>) : never;
/**
 * Asserts that a value is a byte array and optionally checks its length.
 * Returns the original reference unchanged on success, and currently also accepts Node `Buffer`
 * values through the upstream validator.
 * This helper throws on malformed input, so APIs that must return `false` need to guard lengths
 * before decoding or before calling it.
 * @example
 * Validate that a value is a byte array with the expected length.
 * ```ts
 * abytes(new Uint8Array([1]), 1);
 * ```
 */
declare const abytesDoc: typeof abytes;
export { abytesDoc as abytes };
/**
 * Concatenates byte arrays into a new `Uint8Array`.
 * Zero arguments return an empty `Uint8Array`.
 * Invalid segments throw before allocation because each argument is validated first.
 * @example
 * Concatenate two byte arrays into one result.
 * ```ts
 * concatBytes(new Uint8Array([1]), new Uint8Array([2]));
 * ```
 */
declare const concatBytesDoc: typeof concatBytes;
export { concatBytesDoc as concatBytes };
/**
 * Returns cryptographically secure random bytes.
 * Requires `globalThis.crypto.getRandomValues` and throws if that API is unavailable.
 * `bytesLength` is validated by the upstream helper as a non-negative integer before allocation,
 * so negative and fractional values both throw instead of truncating through JS `ToIndex`.
 * @param bytesLength - Number of random bytes to generate.
 * @returns Fresh random bytes.
 * @example
 * Generate a fresh random seed.
 * ```ts
 * const seed = randomBytes(4);
 * ```
 */
export declare const randomBytes: typeof randb;
/**
 * Compares two byte arrays in a length-constant way for equal lengths.
 * Unequal lengths return `false` immediately, and there is no runtime type validation.
 * @param a - First byte array.
 * @param b - Second byte array.
 * @returns Whether both arrays contain the same bytes.
 * @example
 * Compare two byte arrays for equality.
 * ```ts
 * equalBytes(new Uint8Array([1]), new Uint8Array([1]));
 * ```
 */
export declare function equalBytes(a: TArg<Uint8Array>, b: TArg<Uint8Array>): boolean;
/**
 * Copies bytes into a fresh `Uint8Array`.
 * Returns a detached plain `Uint8Array` after validating that the input is real bytes.
 * @param bytes - Source bytes.
 * @returns Copy of the input bytes.
 * @example
 * Copy bytes into a fresh array.
 * ```ts
 * copyBytes(new Uint8Array([1, 2]));
 * ```
 */
export declare function copyBytes(bytes: TArg<Uint8Array>): TRet<Uint8Array>;
/**
 * Byte-swaps each 64-bit lane in place.
 * Falcon's exact binary64 tables are stored as little-endian byte payloads, so BE runtimes need
 * this boundary helper before aliasing them as host `Float64Array` lanes.
 * @param arr - Byte buffer whose length is a multiple of 8.
 * @returns The same buffer after in-place 64-bit lane byte swaps.
 * @example
 * Byte-swap one 64-bit lane in place.
 * ```ts
 * byteSwap64(new Uint8Array([1, 2, 3, 4, 5, 6, 7, 8]));
 * ```
 */
export declare function byteSwap64<T extends ArrayBufferView>(arr: T): T;
/**
 * Byte-swaps 64-bit lanes on big-endian runtimes and returns the input unchanged on little-endian.
 * This keeps Falcon's binary64 tables in canonical little-endian order before aliasing them as
 * `Float64Array` lanes on the current host.
 * @param arr - Buffer to pass through or swap in place.
 * @returns The same buffer, normalized for Falcon's little-endian table layout.
 * @example
 * Normalize one host-endian buffer for Falcon's float tables.
 * ```ts
 * baswap64If(new Uint8Array([1, 2, 3, 4, 5, 6, 7, 8]));
 * ```
 */
export declare const baswap64If: <T extends ArrayBufferView>(arr: T) => T;
/** Shared key-generation surface for signers and KEMs. */
export type CryptoKeys = {
    /** Optional metadata about the algorithm family or variant. */
    info?: {
        type?: string;
    };
    /** Public byte lengths for the exported key material. */
    lengths: {
        seed?: number;
        publicKey?: number;
        secretKey?: number;
    };
    /**
     * Generate one secret/public keypair.
     * @param seed - Optional seed bytes for deterministic key generation.
     * @returns Fresh secret/public keypair.
     */
    keygen: (seed?: TArg<Uint8Array>) => {
        secretKey: TRet<Uint8Array>;
        publicKey: TRet<Uint8Array>;
    };
    /**
     * Derive one public key from a secret key.
     * @param secretKey - Secret key bytes.
     * @returns Public key bytes.
     */
    getPublicKey: (secretKey: TArg<Uint8Array>) => TRet<Uint8Array>;
};
/** Verification options shared by the signature APIs. */
export type VerOpts = {
    /** Optional application-defined context string. */
    context?: Uint8Array;
};
/** Signing options shared by the signature APIs. */
export type SigOpts = VerOpts & {
    /** Optional extra entropy or `false` to disable randomized signing. */
    extraEntropy?: Uint8Array | false;
};
/**
 * Validates that an options bag is a plain object.
 * @param opts - Options object to validate.
 * @throws On wrong argument types. {@link TypeError}
 * @example
 * Validate that an options bag is a plain object.
 * ```ts
 * validateOpts({});
 * ```
 */
export declare function validateOpts(opts: object): void;
/**
 * Validates common verification options.
 * `context` itself is validated with `abytes(...)`, and individual algorithms may narrow support
 * further after this shared plain-object gate.
 * @param opts - Verification options. See {@link VerOpts}.
 * @throws On wrong argument types. {@link TypeError}
 * @example
 * Validate common verification options.
 * ```ts
 * validateVerOpts({ context: new Uint8Array([1]) });
 * ```
 */
export declare function validateVerOpts(opts: TArg<VerOpts>): void;
/**
 * Validates common signing options.
 * `extraEntropy` is validated with `abytes(...)`; exact lengths and extra algorithm-specific
 * restrictions are enforced later by callers.
 * @param opts - Signing options. See {@link SigOpts}.
 * @throws On wrong argument types. {@link TypeError}
 * @example
 * Validate common signing options.
 * ```ts
 * validateSigOpts({ extraEntropy: new Uint8Array([1]) });
 * ```
 */
export declare function validateSigOpts(opts: TArg<SigOpts>): void;
/** Generic signature interface with key generation, signing, and verification. */
export type Signer = CryptoKeys & {
    /** Public byte lengths for signatures and signing randomness. */
    lengths: {
        signRand?: number;
        signature?: number;
    };
    /**
     * Sign one message.
     * @param msg - Message bytes to sign.
     * @param secretKey - Secret key bytes.
     * @param opts - Optional signing options.
     * @returns Signature bytes.
     */
    sign: (msg: TArg<Uint8Array>, secretKey: TArg<Uint8Array>, opts?: TArg<SigOpts>) => TRet<Uint8Array>;
    /**
     * Verify one signature.
     * @param sig - Signature bytes.
     * @param msg - Signed message bytes.
     * @param publicKey - Public key bytes.
     * @param opts - Optional verification options.
     * @returns `true` when the signature is valid, `false` when all inputs are well-formed but the
     * signature check does not pass. Some implementations also treat malformed signature encodings as
     * a verification failure and return `false`.
     * @throws On malformed API arguments or unsupported verification options.
     */
    verify: (sig: TArg<Uint8Array>, msg: TArg<Uint8Array>, publicKey: TArg<Uint8Array>, opts?: TArg<VerOpts>) => boolean;
};
/** Generic key encapsulation mechanism interface. */
export type KEM = CryptoKeys & {
    /** Public byte lengths for ciphertexts and optional message randomness. */
    lengths: {
        cipherText?: number;
        msg?: number;
        msgRand?: number;
    };
    /**
     * Encapsulate one shared secret to a recipient public key.
     * @param publicKey - Recipient public key bytes.
     * @param msg - Optional caller-provided randomness/message seed.
     * @returns Ciphertext plus shared secret.
     */
    encapsulate: (publicKey: TArg<Uint8Array>, msg?: TArg<Uint8Array>) => {
        cipherText: TRet<Uint8Array>;
        sharedSecret: TRet<Uint8Array>;
    };
    /**
     * Recover the shared secret from a ciphertext and recipient secret key.
     * @param cipherText - Ciphertext bytes.
     * @param secretKey - Recipient secret key bytes.
     * @returns Decapsulated shared secret.
     */
    decapsulate: (cipherText: TArg<Uint8Array>, secretKey: TArg<Uint8Array>) => TRet<Uint8Array>;
};
/** Bidirectional encoder/decoder interface. */
export interface Coder<F, T> {
    /**
     * Serialize one value.
     * @param from - Value to encode.
     * @returns Encoded representation.
     */
    encode(from: F): T;
    /**
     * Parse one serialized value.
     * @param to - Encoded representation.
     * @returns Decoded value.
     */
    decode(to: T): F;
}
/** Encoder/decoder interface specialized for byte arrays. */
export interface BytesCoder<T> extends Coder<T, Uint8Array> {
    /**
     * Serialize one value into bytes.
     * @param data - Value to encode.
     * @returns Encoded bytes.
     */
    encode: (data: T) => Uint8Array;
    /**
     * Parse one byte array into a value.
     * @param bytes - Encoded bytes.
     * @returns Decoded value.
     */
    decode: (bytes: Uint8Array) => T;
}
/** Fixed-length byte encoder/decoder. */
export type BytesCoderLen<T> = BytesCoder<T> & {
    bytesLen: number;
};
type UnCoder<T> = T extends BytesCoder<infer U> ? U : never;
type SplitOut<T extends (number | BytesCoderLen<any>)[]> = {
    [K in keyof T]: T[K] extends number ? Uint8Array : UnCoder<T[K]>;
};
/**
 * Builds a fixed-layout coder from byte lengths and nested coders.
 * Raw-length fields decode as zero-copy `subarray(...)` views, and nested coders may preserve that
 * aliasing too. Nested coder `encode(...)` results are treated as owned scratch: `splitCoder`
 * copies them into the output and then zeroizes them with `fill(0)`. If a nested encoder forwards
 * caller-owned bytes, it must do so only after detaching them into a disposable copy.
 * @param label - Label used in validation errors.
 * @param lengths - Field lengths or nested coders.
 * @returns Composite fixed-length coder.
 * @example
 * Build a fixed-layout coder from byte lengths and nested coders.
 * ```ts
 * splitCoder('demo', 1, 2).encode([new Uint8Array([1]), new Uint8Array([2, 3])]);
 * ```
 */
export declare function splitCoder<T extends (number | BytesCoderLen<any>)[]>(label: string, ...lengths: T): TRet<BytesCoder<SplitOut<T>> & {
    bytesLen: number;
}>;
/**
 * Builds a fixed-length vector coder from another fixed-length coder.
 * Element decoding receives `subarray(...)` views, so aliasing depends on the element coder.
 * Element coder `encode(...)` results are treated as owned scratch: `vecCoder` copies them into
 * the output and then zeroizes them with `fill(0)`. If an element encoder forwards caller-owned
 * bytes, it must do so only after detaching them into a disposable copy. `vecCoder` also trusts
 * the `BytesCoderLen` contract: each encoded element must already be exactly `c.bytesLen` bytes.
 * @param c - Element coder.
 * @param vecLen - Number of elements in the vector.
 * @returns Fixed-length vector coder.
 * @example
 * Build a fixed-length vector coder from another fixed-length coder.
 * ```ts
 * vecCoder(
 *   { bytesLen: 1, encode: (n: number) => Uint8Array.of(n), decode: (b: Uint8Array) => b[0] || 0 },
 *   2
 * ).encode([1, 2]);
 * ```
 */
export declare function vecCoder<T>(c: TArg<BytesCoderLen<T>>, vecLen: number): TRet<BytesCoderLen<T[]>>;
/**
 * Overwrites supported typed-array inputs with zeroes in place.
 * Accepts direct typed arrays and one-level arrays of them.
 * @param list - Typed arrays or one-level lists of typed arrays to clear.
 * @example
 * Overwrite typed arrays with zeroes.
 * ```ts
 * const buf = Uint8Array.of(1, 2, 3);
 * cleanBytes(buf);
 * ```
 */
export declare function cleanBytes(...list: (TypedArray | TypedArray[])[]): void;
/**
 * Creates a 32-bit mask with the lowest `bits` bits set.
 * @param bits - Number of low bits to keep.
 * @returns Bit mask with `bits` ones.
 * @throws On wrong argument ranges or values. {@link RangeError}
 * @example
 * Create a low-bit mask for packed-field operations.
 * ```ts
 * const mask = getMask(4);
 * ```
 */
export declare function getMask(bits: number): number;
/** Shared empty byte array used as the default context. */
export declare const EMPTY: TRet<Uint8Array>;
/**
 * Builds the domain-separated message payload for the pure sign/verify paths.
 * Context length `255` is valid; only `ctx.length > 255` is rejected.
 * @param msg - Message bytes.
 * @param ctx - Optional context bytes.
 * @returns Domain-separated message payload.
 * @throws On wrong argument ranges or values. {@link RangeError}
 * @example
 * Build the domain-separated payload before direct signing.
 * ```ts
 * const payload = getMessage(new Uint8Array([1, 2]));
 * ```
 */
export declare function getMessage(msg: TArg<Uint8Array>, ctx?: TArg<Uint8Array>): TRet<Uint8Array>;
/**
 * Validates that a hash exposes a NIST hash OID and enough collision resistance.
 * Current accepted surface is broader than the FIPS algorithm tables: any hash/XOF under the NIST
 * `2.16.840.1.101.3.4.2.*` subtree is accepted if its effective `outputLen` is strong enough.
 * XOF callers must pass a callable whose `outputLen` matches the digest length they actually intend
 * to sign; bare `shake128` / `shake256` defaults are too short for the stronger prehash modes.
 * @param hash - Hash function to validate.
 * @param requiredStrength - Minimum required collision-resistance strength in bits.
 * @throws If the hash metadata or collision resistance is insufficient. {@link Error}
 * @example
 * Validate that a hash exposes a NIST hash OID and enough collision resistance.
 * ```ts
 * import { sha256 } from '@noble/hashes/sha2.js';
 * import { checkHash } from '@noble/post-quantum/utils.js';
 * checkHash(sha256, 128);
 * ```
 */
export declare function checkHash(hash: CHash, requiredStrength?: number): void;
/**
 * Builds the domain-separated prehash payload for the prehash sign/verify paths.
 * Callers are expected to vet `hash.oid` first, e.g. via `checkHash(...)`; calling this helper
 * directly with a hash object that lacks `oid` currently throws later inside `concatBytes(...)`.
 * Context length `255` is valid; only `ctx.length > 255` is rejected.
 * @param hash - Prehash function.
 * @param msg - Message bytes.
 * @param ctx - Optional context bytes.
 * @returns Domain-separated prehash payload.
 * @throws On wrong argument ranges or values. {@link RangeError}
 * @example
 * Build the domain-separated prehash payload for external hashing.
 * ```ts
 * import { sha256 } from '@noble/hashes/sha2.js';
 * import { getMessagePrehash } from '@noble/post-quantum/utils.js';
 * getMessagePrehash(sha256, new Uint8Array([1, 2]));
 * ```
 */
export declare function getMessagePrehash(hash: CHash, msg: TArg<Uint8Array>, ctx?: TArg<Uint8Array>): TRet<Uint8Array>;
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