export declare function utf8Encode(value: string): Uint8Array;
export declare function utf8Decode(value: Uint8Array): string;
export declare function toBase64(value: Uint8Array): string;
/**
 * Decodes base64 in either alphabet, with or without padding.
 *
 * Values reaching an SDK are written by whatever device produced them, and the
 * SDKs did not agree on which alphabet to use: each could read its own and none
 * could read the others, so two people on different platforms could not send to
 * each other at all. `atob` is strict, so the input is normalised first.
 */
export declare function fromBase64(value: string): Uint8Array;
export declare function randomBytes(length: number): Uint8Array;
export declare function concatBytes(...parts: Uint8Array[]): Uint8Array;
export declare function isJwtExpired(jwt: string): boolean;
export declare function parseJwtPayload(jwt: string): Record<string, unknown>;