export interface PayloadFields {
    keyId: string;
    timestamp: number;
    nonce: string;
    method: string;
    path: string;
    bodyHash: string;
    /** Hex hash of the canonicalized query params. Omit entirely (not "")
     *  when there are no params, to keep payloads byte-identical to
     *  requests that never had params. */
    paramsHash?: string;
}
export declare function buildSigningPayload(fields: PayloadFields): Uint8Array;
/** Canonical, order-independent query-string encoding for GET-style params.
 *  Returns undefined (not "") when there are no params, so callers can
 *  omit `paramsHash` entirely rather than hashing an empty string. */
export declare function canonicalizeParams(params?: Record<string, string | number | boolean | null | undefined>): string | undefined;