/**
 * OpenTimestamps anchor adapter.
 *
 * Submits ONLY the 32-byte SHA-256 of the chain head to one or more public
 * OpenTimestamps calendar servers, stores the returned `.ots` proof, and can
 * later upgrade that proof to a Bitcoin block attestation. Nothing else leaves
 * the process (zero data plane): a hash is submitted, an `.ots` proof comes
 * back. No decision content, policy, scope, amount, model identity, or key
 * material is ever transmitted.
 *
 * This adapter uses the real `opentimestamps` npm library through an injectable
 * boundary (`OtsLib`), so:
 *   - `anchor()` builds a `DetachedTimestampFile` from the raw digest, stamps it
 *     against public calendars, and stores the serialized `.ots` bytes,
 *   - `upgrade()` fetches the Bitcoin attestation when the calendars have it and
 *     persists the upgraded `.ots` (idempotent),
 *   - `verify()` reports `attested: true` with a real `when` ONLY when the `.ots`
 *     proof actually carries a Bitcoin block-header attestation. A pending proof
 *     stays pending. An attested time is NEVER fabricated.
 *
 * Patent notice: Protected by U.S. patent-pending technology
 * (App. Nos. 63/983,615; 63/983,621; 63/983,843; 63/984,626;
 * 64/071,781; 64/071,789).
 */
import type { AnchorProof, AnchorVerification, TimestampAnchor } from './types';
/** Public OpenTimestamps calendar servers (aggregators). */
export declare const DEFAULT_OTS_CALENDARS: string[];
/**
 * Result of inspecting an `.ots` proof for a Bitcoin attestation.
 * `bitcoinAttested` is true iff the timestamp carries a Bitcoin block-header
 * attestation; `attestedTimeSec` is the confirmed block time (unix seconds),
 * only present when the attestation resolves to a real time.
 */
export interface OtsBitcoinAttestation {
    bitcoinAttested: boolean;
    attestedTimeSec?: number;
    height?: number;
}
/**
 * The `opentimestamps` library boundary. Injectable so tests are deterministic
 * and never touch the network. Every method receives/returns raw bytes and the
 * 32-byte digest only — zero data plane.
 */
export interface OtsLib {
    /** Stamp a 32-byte SHA-256 digest against calendars; return the `.ots` bytes. */
    stamp(sha256Digest: Uint8Array, calendars: string[]): Promise<Uint8Array>;
    /** Upgrade stored `.ots` bytes (fetch Bitcoin attestation if available). Idempotent; returns the possibly-upgraded `.ots` bytes. */
    upgrade(otsBytes: Uint8Array): Promise<Uint8Array>;
    /** Inspect `.ots` bytes for the given digest. MUST throw if the proof's embedded file hash does not equal `sha256Digest`. */
    verify(sha256Digest: Uint8Array, otsBytes: Uint8Array): Promise<OtsBitcoinAttestation>;
}
/**
 * @deprecated Legacy calendar-POST transport hook. Superseded by the `OtsLib`
 * boundary now that the real `opentimestamps` library is a dependency. Retained
 * only so existing type imports keep compiling.
 */
export type OtsSubmit = (calendarUrl: string, digest: Uint8Array) => Promise<Uint8Array>;
export interface OpenTimestampsAnchorOptions {
    calendars?: string[];
    /** Override the OpenTimestamps library boundary (defaults to the real npm lib). */
    lib?: OtsLib;
}
/**
 * Default `OtsLib` backed by the real `opentimestamps` npm package. Lazily
 * required so the SDK never pulls the library (or node:https) at import time in
 * bundlers — only when an anchor is actually exercised.
 */
export declare function defaultOtsLib(): OtsLib;
export declare class OpenTimestampsAnchor implements TimestampAnchor {
    readonly type = "opentimestamps";
    private readonly calendars;
    private lazyLib;
    constructor(options?: OpenTimestampsAnchorOptions);
    private lib;
    private digestOf;
    anchor(headHashHex: string): Promise<AnchorProof>;
    /**
     * Fetch the Bitcoin attestation for a stored proof, if the calendars now have
     * it, and return an updated proof. Idempotent: safe to call repeatedly. If the
     * attestation is confirmable, `attestedAt` is set to the real Bitcoin block
     * time and status becomes `complete`; otherwise the proof stays `pending`.
     */
    upgrade(proof: AnchorProof): Promise<AnchorProof>;
    verify(headHashHex: string, proof: AnchorProof): Promise<AnchorVerification>;
}
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