import type { CipherSuite } from '../stream/types.js';
/**
 * `CipherSuite` implementation for the stream construction using Serpent-256.
 *
 * Each chunk is encrypted with Serpent-CBC (PKCS7) and authenticated with
 * HMAC-SHA-256. Keys are derived via 3-way HKDF-SHA-256 (enc / mac / iv keys).
 * Verify-then-decrypt ordering prevents padding oracle attacks (Vaudenay 2002).
 *
 * Pass to `SealStream` / `OpenStream` / `SealStreamPool` instead of constructing
 * this object directly. Use `SerpentCipher.keygen()` to generate a 32-byte key.
 */
export declare const SerpentCipher: CipherSuite & {
    keygen(): Uint8Array;
};