export declare class JwtHelper {
    protected static getJwtKey(param?: string): string;
    static sign(value: any, options?: {
        expiresIn?: string;
        jwtKeyParam?: string;
    }): Promise<string>;
    static verify(value: any, options?: {
        jwtKeyParam?: string;
    }): Promise<object | string>;
    static isExpired(token: string): boolean;
}