/**
 * Decodes a base64 string to a byte array.
 *
 * - ignores white-space, including line breaks and tabs
 * - allows inner padding (can decode concatenated base64 strings)
 * - does not require padding
 * - understands base64url encoding:
 *   "-" instead of "+",
 *   "_" instead of "/",
 *   no padding
 */
export declare function base64decode(base64Str: string): Uint8Array;
/**
 * Encodes a byte array to a base64 string.
 * Adds padding at the end.
 * Does not insert newlines.
 */
export declare function base64encode(bytes: Uint8Array): string;