/**
 * Cryptographic primitives — Browser version.
 *
 * Uses pure JavaScript for synchronous operations (SHA-256, MD5, AES-CBC, RC4)
 * since Web Crypto API is async-only and cannot replace synchronous call sites.
 *
 * Uses Web Crypto API for:
 * - `randomBytes` (crypto.getRandomValues — truly random)
 * - `rsaVerify` / `rsaSign` (SubtleCrypto — hardware-accelerated)
 *
 * Exports the same API as `crypto.ts` (Node.js version).
 */
export declare function aesCbcEncrypt(plaintext: Uint8Array, key: Uint8Array, iv: Uint8Array): Uint8Array;
export declare function aesCbcDecrypt(ciphertext: Uint8Array, key: Uint8Array, iv: Uint8Array): Uint8Array;
export declare function aesCbcDecryptRaw(ciphertext: Uint8Array, key: Uint8Array, iv: Uint8Array): Uint8Array;
export declare function aesCbcEncryptRaw(plaintext: Uint8Array, key: Uint8Array, iv: Uint8Array): Uint8Array;
export declare function aesEcbEncrypt(block: Uint8Array, key: Uint8Array): Uint8Array;
export declare function sha256(input: Uint8Array): Uint8Array;
export declare function md5(input: Uint8Array): Uint8Array;
/**
 * RC4 stream cipher.
 *
 * Required by ISO 32000 for reading PDFs encrypted with the RC4 algorithm
 * (PDF 1.4 standard handler V=1/V=2).
 */
export declare function rc4(key: Uint8Array, data: Uint8Array): Uint8Array;
/**
 * Generate cryptographically secure random bytes.
 * Uses crypto.getRandomValues (available in all modern browsers).
 */
export declare function randomBytes(length: number): Uint8Array;
/**
 * Compute a hash digest using Web Crypto API.
 *
 * NOTE: In the browser, this is async. The Node.js version is sync.
 * For callers that need sync hashing, use `sha256()` or `md5()` directly.
 *
 * @param algorithm - Hash algorithm name (e.g., "SHA-256", "SHA-512", "SHA-1").
 * @param data - Data to hash
 * @returns The digest bytes
 */
export declare function hashAsync(algorithm: string, data: Uint8Array): Promise<Uint8Array>;
/**
 * Compute a hash digest synchronously (pure JS — SHA-256 and MD5 only).
 *
 * @param algorithm - "SHA-256" or "MD5" (case-insensitive, hyphens optional)
 * @param data - Data to hash
 * @returns The digest bytes
 * @throws If algorithm is not SHA-256 or MD5
 */
export declare function hash(algorithm: string, data: Uint8Array): Uint8Array;
/**
 * Verify an RSA PKCS#1 v1.5 signature.
 *
 * @param publicKeyDer - DER-encoded SubjectPublicKeyInfo
 * @param signature - The signature bytes
 * @param data - The signed data (will be hashed with SHA-256)
 */
export declare function rsaVerify(publicKeyDer: Uint8Array, signature: Uint8Array, data: Uint8Array): Promise<boolean>;
/**
 * Create an RSA PKCS#1 v1.5 signature.
 *
 * @param privateKeyDer - DER-encoded PKCS#8 private key
 * @param data - The data to sign (will be hashed with SHA-256)
 */
export declare function rsaSign(privateKeyDer: Uint8Array, data: Uint8Array): Promise<Uint8Array>;