/**
 * Base cipher interface for internal cipher implementations.
 *
 * @private
 */
export declare abstract class _Cipher {
    /**
     * Decrypt a block of data.
     *
     * @private
     * @param {Uint8Array} data - Data to decrypt.
     * @param {boolean} [finalize] - Whether this is the final block.
     * @param {Uint8Array} [iv] - Optional initialization vector.
     * @returns {Uint8Array} Decrypted bytes.
     */
    abstract _decryptBlock(data: Uint8Array, finalize?: boolean, iv?: Uint8Array): Uint8Array;
    /**
     * Encrypt a block of data.
     *
     * @private
     * @param {Uint8Array} data - Data to encrypt.
     * @returns {Uint8Array} Encrypted bytes.
     */
    abstract _encrypt(data: Uint8Array): Uint8Array;
}
/**
 * AES-like advanced encryption base used internally for PDF encryption ciphers.
 *
 * @private
 */
export declare abstract class _AdvancedEncryptionBaseCipher extends _Cipher {
    /**
     * Cached mix column lookup table.
     *
     * @private
     */
    _mixC: Uint8Array;
    /**
     * Buffer used for partial block accumulation.
     *
     * @private
     */
    _buffer: Uint8Array;
    /**
     * Current buffer write position.
     *
     * @private
     */
    _position: number;
    /**
     * Key size in bytes used by this cipher instance.
     *
     * @private
     */
    _keySize: number;
    /**
     * Number of cipher rounds.
     *
     * @private
     */
    _cyclesOfRepetition: number;
    /**
     * Initialization vector for streaming operations.
     *
     * @private
     */
    _iv: Uint8Array;
    /**
     * The expanded key schedule.
     *
     * @private
     */
    _key: Uint8Array;
    /**
     * Length of data currently in the buffer.
     *
     * @private
     */
    _bufferLength: number;
    /**
     * Substitution box used for byte substitution.
     *
     * @private
     */
    _s: Uint8Array;
    /**
     * Inverse S-box used for decryption.
     *
     * @private
     */
    _inverseS: Uint8Array;
    /**
     * Mix column table used in block transformations.
     *
     * @private
     */
    _mix: Uint32Array;
    /**
     * Lazily-created mix column byte table.
     *
     * @private
     * @returns {Uint8Array} The mix column table as a `Uint8Array`.
     */
    readonly _mixCol: Uint8Array;
    /**
     * Expand a cipher key into the full key schedule.
     *
     * @private
     * @param {Uint8Array} cipherKey - The raw cipher key bytes.
     * @returns {Uint8Array} The expanded key schedule.
     */
    abstract _expandKey(cipherKey: Uint8Array): Uint8Array;
    /**
     * Core single-block decryption routine.
     *
     * @private
     * @param {Uint8Array} input - 16-byte input block.
     * @param {Uint8Array} key - Expanded key schedule.
     * @returns {Uint8Array} Decrypted 16-byte block.
     */
    _decrypt(input: Uint8Array, key: Uint8Array): Uint8Array;
    /**
     * Core single-block encryption routine.
     *
     * @private
     * @param {Uint8Array} input - 16-byte input block.
     * @param {Uint8Array} key - Expanded key schedule.
     * @returns {Uint8Array} Encrypted 16-byte block.
     */
    _encryptBlock(input: Uint8Array, key: Uint8Array): Uint8Array;
    /**
     * Helper that decrypts a sequence of bytes using internal buffering.
     *
     * @private
     * @param {Uint8Array} data - Input bytes to decrypt.
     * @param {boolean} finalize - Whether to finalize (remove padding) for the last block.
     * @returns {Uint8Array} Decrypted bytes.
     */
    _decryptBlockHelper(data: Uint8Array, finalize: boolean): Uint8Array;
    /**
     * Public-facing decrypt block implementation that sets up IV and buffering.
     *
     * @private
     * @param {Uint8Array} data - Input data to decrypt.
     * @param {boolean} finalize - Whether this is the final call (remove padding).
     * @param {Uint8Array} [iv] - Optional initialization vector for decryption.
     * @returns {Uint8Array} Decrypted bytes.
     */
    _decryptBlock(data: Uint8Array, finalize: boolean, iv?: Uint8Array): Uint8Array;
    /**
     * Encrypt data using streaming semantics and internal buffering.
     *
     * @private
     * @param {Uint8Array} data - Bytes to encrypt.
     * @param {Uint8Array} [iv] - Optional initialization vector.
     * @returns {Uint8Array} Encrypted bytes.
     */
    _encrypt(data: Uint8Array, iv?: Uint8Array): Uint8Array;
}