export type StreamingKey = Uint8Array;
export declare function sealChunkXChaCha(key: StreamingKey, noncePrefix16: Uint8Array, seq: number, plaintext: Uint8Array, aad?: Uint8Array): Promise<Uint8Array>;
export declare function openChunkXChaCha(key: StreamingKey, noncePrefix16: Uint8Array, seq: number, ciphertext: Uint8Array, aad?: Uint8Array): Promise<Uint8Array>;
export declare class XChaChaStreamLimiter {
    private readonly key;
    private readonly prefix;
    private readonly maxChunks;
    private readonly maxBytes;
    private chunksUsed;
    private bytesUsed;
    constructor(key: StreamingKey, noncePrefix16: Uint8Array, opts?: {
        maxChunks?: number;
        maxBytes?: number;
    });
    private enforceLimits;
    seal(seq: number, chunk: Uint8Array, aad?: Uint8Array): Promise<Uint8Array>;
    open(seq: number, ct: Uint8Array, aad?: Uint8Array): Promise<Uint8Array>;
}