/**
 * JWT Utilities
 *
 * Provides functions for decoding and validating JWT tokens.
 * NOTE: These functions do NOT verify signatures - they are for
 * expiration checking and display purposes only.
 */
export interface JwtPayload {
    sub?: string;
    exp?: number;
    iat?: number;
    [key: string]: unknown;
}
/**
 * Decode JWT payload without signature verification.
 * ONLY for expiration checking and display purposes.
 */
export declare function decodeJwtPayload(token: string): JwtPayload | null;
/**
 * Check if a token is expiring soon (within threshold seconds).
 * Default threshold is 5 minutes (300 seconds).
 */
export declare function isTokenExpiringSoon(token: string, thresholdSeconds?: number): boolean;
/**
 * Check if a token has expired.
 */
export declare function isTokenExpired(token: string): boolean;
/**
 * Get the time remaining until token expiration in seconds.
 * Returns negative value if expired.
 */
export declare function getTokenTimeRemaining(token: string): number;
/**
 * Format seconds into human-readable duration.
 */
export declare function formatDuration(seconds: number): string;
/**
 * Mask sensitive token data for display.
 */
export declare function maskToken(token: string | undefined): string;