/**
 * Web Crypto helpers shared across runtime targets (Cloudflare Workers, Node
 * 19+, browsers). Built on `crypto.subtle` so the same implementation runs
 * inside Workers without a Node-only `node:crypto` import.
 */
export declare function bytesToBase64Url(bytes: Uint8Array): string;
export declare function base64UrlToBytes(input: string): Uint8Array;
export declare function randomBase64Url(byteLength: number): string;
/**
 * Prefer this over the global `crypto.randomUUID()`, which is secure-context-only
 * and therefore undefined over plain `http://`. `uuid`'s v4 is backed by
 * `crypto.getRandomValues`, which carries no such restriction.
 */
export declare function randomUUID(): string;
/** Strings use UTF-8; binary inputs are hashed unchanged. */
export declare function sha256Hex(input: string | Parameters<typeof crypto.subtle.digest>[1]): Promise<string>;
export declare function constantTimeEqual({ left, right, }: {
    left: Uint8Array;
    right: Uint8Array;
}): boolean;
export declare function getHmacSha256Hex({ rawBody, signingKey, }: {
    rawBody: string;
    signingKey: string;
}): Promise<string>;
export declare function deterministicUUID(value: string): string;