/// <reference types="node" />
/**
 * Outer connection protocol.
 * Has two modes, DVC and normal (telnet?). Starts in DVC mode.
 *
 * This layer basically takes care of encryption / decryption.
 */
export declare class Telnet {
    protected key: Buffer;
    protected ciphers: {
        [enc: number]: [CipherFn, CipherFn];
    };
    protected cipher: DvcEncryption;
    protected state: {
        dvcMode: false;
        ctr1: number;
    } | {
        dvcMode: true;
        encryption: boolean;
    };
    constructor(key: Buffer);
    receive(b: number): void;
    sendDvc(data: Buffer): void;
    setDvcWithEncryption(enc: DvcEncryption): void;
    initializeCipherInstances(enc: DvcEncryption): void;
    exitDvc(): void;
    protected receiveDvc(b: number): void;
    protected send(data: Buffer): void;
}
/**
 * Defines the cipher used for encryption / decryption.
 *
 * The cipher is always used as a **stream cipher**, i.e.
 * block ciphers are used in OFB mode (so decryption and
 * encryption are the same operation). IV is zero.
 */
export declare enum DvcEncryption {
    NONE = 0,
    RC4 = 1,
    AES128 = 2,
    AES256 = 3
}
declare type CipherFn = (data: Buffer) => Buffer;
export default Telnet;