import { _AdvancedEncryptionBaseCipher } from './cipher';
/**
 * Advanced AES-128 encryption cipher helper used internally for PDF encryption.
 *
 * @private
 */
export declare class _AdvancedEncryption128Cipher extends _AdvancedEncryptionBaseCipher {
    /**
     * The expanded key schedule used by the cipher.
     *
     * @private
     */
    _key: Uint8Array;
    constructor(key: Uint8Array);
    /**
     * Expands the provided cipher key into the full AES key schedule.
     *
     * @private
     * @param {Uint8Array} cipherKey - The original cipher key to expand.
     * @returns {Uint8Array} The expanded key schedule as a `Uint8Array`.
     */
    _expandKey(cipherKey: Uint8Array): Uint8Array;
}
/**
 * Advanced AES-256 encryption cipher helper used internally for PDF encryption.
 *
 * @private
 */
export declare class _AdvancedEncryption256Cipher extends _AdvancedEncryptionBaseCipher {
    constructor(key: Uint8Array);
    /**
     * Expands the provided cipher key into the full AES-256 key schedule.
     *
     * @private
     * @param {Uint16Array} cipherKey - The original cipher key to expand.
     * @returns {Uint8Array} The expanded key schedule as a `Uint8Array`.
     */
    _expandKey(cipherKey: Uint8Array): Uint8Array;
}