/**
 * Generate a CUID2-like identifier using Node.js crypto
 *
 * This is a simplified, zero-dependency implementation of CUID2 concepts:
 * - Uses native Node.js crypto instead of @noble/hashes
 * - Maintains similar structure: letter + hash of (time + entropy + counter)
 * - Provides collision-resistant, sortable, URL-safe IDs
 *
 * @param length - Length of the generated ID (default: 24)
 * @returns A CUID2-like identifier string
 */
export declare function createId(length?: number): string;
/**
 * Convert base64 to base64url encoding
 * base64url is the URL-safe variant of base64 used in JWTs
 *
 * @param base64 - Standard base64 encoded string
 * @returns base64url encoded string
 */
export declare function base64ToBase64Url(base64: string): string;
/**
 * Convert base64url to base64 encoding
 * Converts JWT-style base64url back to standard base64
 *
 * @param base64url - base64url encoded string
 * @returns Standard base64 encoded string
 */
export declare function base64UrlToBase64(base64url: string): string;