import { ByteArray } from '../../types.js';
/**
 * Computes the Algorithm 2.B hash for PDF 2.0 AES-256 encryption.
 * This iterative hash algorithm uses SHA-256, SHA-384, or SHA-512 based on
 * intermediate results, running for at least 64 rounds.
 *
 * @param password - The user or owner password.
 * @param salt - The 8-byte validation or key salt.
 * @param userKey - The user key (required for owner password validation). Defaults to empty.
 * @returns A promise that resolves to a 32-byte hash.
 *
 * @example
 * ```typescript
 * const hash = await computeAlgorithm2bHash(password, salt)
 * ```
 */
export declare function computeAlgorithm2bHash(password: ByteArray, salt: ByteArray, userKey?: ByteArray): Promise<ByteArray>;
/**
 * Validates a password against a stored hash using the Algorithm 2.B hash.
 *
 * @param password - The password to validate.
 * @param key - The stored key containing the hash (first 32 bytes) and validation salt (bytes 32-40).
 * @param extra - Extra data for owner password validation (user key).
 * @returns A promise that resolves to the computed hash if validation succeeds.
 * @throws Error if the password is invalid or salt/hash lengths are incorrect.
 *
 * @example
 * ```typescript
 * try {
 *   await validatePasswordHash(password, storedKey)
 *   console.log('Password is valid')
 * } catch (e) {
 *   console.log('Invalid password')
 * }
 * ```
 */
export declare function validatePasswordHash(password: ByteArray, key: ByteArray, extra?: ByteArray): Promise<ByteArray>;
/**
 * Retrieves the file encryption key using user or owner password.
 * Tries owner password first, then falls back to user password.
 *
 * @param userPassword - The user password to try.
 * @param ownerPassword - The owner password to try.
 * @param u - The 48-byte /U value from the encryption dictionary.
 * @param ue - The 32-byte /UE value (encrypted user key).
 * @param o - The 48-byte /O value from the encryption dictionary.
 * @param oe - The 32-byte /OE value (encrypted owner key).
 * @returns A promise that resolves to the 32-byte file encryption key.
 * @throws Error if both passwords are invalid.
 *
 * @example
 * ```typescript
 * const fileKey = await getFileKey(userPw, ownerPw, U, UE, O, OE)
 * ```
 */
export declare function getFileKey(userPassword: ByteArray, ownerPassword: ByteArray, u: ByteArray, ue: ByteArray, o: ByteArray, oe: ByteArray): Promise<ByteArray>;