/**
 * ImmutableLedger - Tamper-Evident Session Logging for EU AI Act Compliance
 *
 * Extends VSIL with persistent Merkle tree-based audit trail.
 * Each event is hashed and added to a Merkle tree per session.
 * Supports inclusion proofs for audit verification.
 *
 * EU AI Act Art. 12 (Traceability) & Art. 19 (Transparency obligations)
 */
import { SessionLedger, type HashedEntity, type SessionRiskSummary, type ThreatAnnotation } from '../security/session-ledger.js';
export interface LedgerEvent {
    request_id: string;
    session_id: string;
    timestamp: string;
    url?: string;
    original_hash: string;
    sanitization_steps: string[];
    threats_detected: {
        pattern_id: string;
        severity: string;
        snippet_hash: string;
    }[];
    pii_redacted_count: number;
    pii_types: string[];
    cleaned_hash: string;
    visus_proof: string;
    human_review_flag: boolean;
    human_reviewer_id?: string;
    model_output_hash?: string;
    tool_name?: string;
    entities?: HashedEntity[];
    risk_summary?: SessionRiskSummary;
    new_threats?: ThreatAnnotation[];
}
export interface InclusionProof {
    leaf: string;
    siblings: string[];
    path: number[];
    root: string;
}
export declare class ImmutableLedger extends SessionLedger {
    private trees;
    private ledger_path;
    private enabled;
    private merkle_algo;
    private retention_months;
    constructor();
    private sha256;
    private getOrCreateTree;
    addEvent(sessionId: string, event: Omit<LedgerEvent, 'request_id' | 'timestamp'> & {
        url?: string;
        tool_name?: string;
    }): Promise<{
        merkle_root: string;
        proof: InclusionProof;
    }>;
    getProof(requestId: string): Promise<LedgerEvent & {
        proof: InclusionProof;
    }>;
    verifyProof(proof: InclusionProof, eventData: LedgerEvent): Promise<boolean>;
    purgeOldLedgers(): Promise<void>;
    startRetentionSweep(intervalMs?: number): void;
}
export default ImmutableLedger;
/**
 * Export Ledger Events for Compliance/Audit
 * @param sessionId - Session to export
 * @param outputPath - File path for JSONL export
 * @returns Promise with exported file path and stats
 */
export declare function exportLedger(sessionId: string, outputPath?: string): Promise<{
    file: string;
    eventCount: number;
    merkleRoots: string[];
}>;
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