import { Cipher } from '../../crypto/types.js';
import { PdfCryptFilter, CryptFilterOptions } from './base.js';
/**
 * V2 crypt filter using RC4 encryption.
 * Implements the legacy RC4 stream cipher for PDF encryption.
 *
 * @example
 * ```typescript
 * const filter = new V2CryptFilter({
 *     authEvent: 'DocOpen',
 *     securityHandler,
 *     length: 128
 * })
 * const encrypted = await filter.encrypt(data, objectNumber, generationNumber)
 * ```
 */
export declare class V2CryptFilter extends PdfCryptFilter {
    /**
     * Creates a new V2 crypt filter with RC4 encryption.
     *
     * @param options - Configuration options including key length.
     */
    constructor(options: {
        authEvent: CryptFilterOptions['authEvent'];
        securityHandler?: CryptFilterOptions['securityHandler'];
        length?: number;
    });
    /**
     * Gets an RC4 cipher for encryption/decryption.
     *
     * @param objectNumber - The PDF object number for key derivation.
     * @param generationNumber - The PDF generation number for key derivation.
     * @returns An RC4 cipher instance.
     * @throws Error if security handler is not set.
     */
    getCipher(objectNumber?: number, generationNumber?: number): Promise<Cipher>;
}