export declare const SESSION_MAX_AGE: number;
export interface PasswordHash {
    salt: string;
    hash: string;
}
/** scrypt-hash a password. Pass an existing salt to verify. */
export declare function hashPassword(password: string, salt?: string): PasswordHash;
/** Constant-time password check. */
export declare function verifyPassword(password: string, salt: string, hash: string): boolean;
/** Make a signed session token carrying `uid` and an expiry. */
export declare function makeToken(uid: string, secret: string, maxAgeSeconds?: number): string;
/** Verify a token; returns the uid or null if invalid/expired/tampered. */
export declare function verifyToken(token: string, secret: string): string | null;
/** Generate a random user id. */
export declare function newUserId(bytes?: number): string;