/**
 * base64url encode — no padding, URL/cookie-safe.
 * @param {Buffer | Uint8Array | string} input
 * @returns {string}
 */
export function encodeBase64Url(input: Buffer | Uint8Array | string): string;
/**
 * base64url decode. Throws on invalid characters and non-canonical
 * encodings (strict — everything this package mints is canonical).
 * @param {string} input
 * @returns {Buffer}
 */
export function decodeBase64Url(input: string): Buffer;