import type { AttestationFreshness } from '../types/passport.js';
/**
 * Seconds elapsed since the evidence was produced (`validAt`).
 * Returns 0 if validAt is in the future (clock skew); never negative.
 */
export declare function computeEvidenceAge(freshness: AttestationFreshness, now?: Date): number;
/**
 * Whether the evidence is still fresh for its type.
 *   rotating: now - validAt < ttl (ttl required; missing ttl → not fresh)
 *   snapshot: now - validAt < maxAge; if maxAge omitted → fresh (conservative default)
 *   static:   always true
 */
export declare function isEvidenceFresh(freshness: AttestationFreshness, now?: Date): boolean;
/**
 * Construct a snapshot freshness record (TPM quote, point-in-time attestation).
 * `maxAge` is the recommended staleness window in seconds.
 */
export declare function createSnapshotFreshness(validAt: string, maxAge?: number): AttestationFreshness;
/**
 * Construct a rotating freshness record (SPIFFE SVID, short-lived JWT).
 * `ttl` is the evidence lifetime in seconds.
 */
export declare function createRotatingFreshness(validAt: string, ttl: number): AttestationFreshness;
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