export declare function randomBytesHex(lengthBytes: number): string;
export declare function sha256Hex(input: string | Uint8Array): Promise<string>;
export declare function constantTimeEqual(a: string, b: string): boolean;
export declare function generateNumericCode(length: number): string;
/**
 * SHA-256 hash a string using Web Crypto API.
 * Returns the hash as a base64url string without padding,
 * matching Better Auth's `defaultKeyHasher` format.
 */
export declare function sha256Base64Url(input: string): Promise<string>;
/**
 * Unsign a Better Auth session cookie.
 * Better Auth signs cookies as: encodeURIComponent(value + "." + base64(HMAC-SHA256(value, secret)))
 */
export declare function unsignCookie(rawCookieValue: string, secret: string): Promise<string | null>;