import { Event } from "../async/event.ts"; import { Queue } from "../async/queue.ts"; import { PromiseOrValue } from "../promise.ts"; import { channelEncryption, encryptedMessage, signMessage, VerifiedMessage, verifyMessage, } from "./identity.ts"; import { importJWK } from "./keys.ts"; export interface ChannelEncryption { sendPrivateKey?: CryptoKey; recvPublicKey?: CryptoKey; } export interface Channel { send: (data: Send) => Promise; recv: () => Promise; closed: Event; encryption?: ChannelEncryption; } interface Encryption { sign: (data: string) => Promise; verify: (data: string) => Promise; } const bypassSign: Encryption["sign"] = (data) => Promise.resolve(data); const bypassVerify: Encryption["verify"] = (data) => Promise.resolve({ encoded: data, isValid: true, data }); const useChannelEncryption = (encryption?: ChannelEncryption): Encryption => { const sendPrivateKey = encryption?.sendPrivateKey; const recvPublicKey = encryption?.recvPublicKey; const verify: Encryption["verify"] = recvPublicKey ? (data) => verifyMessage( encryptedMessage.fromString(data), recvPublicKey, ) : bypassVerify; const sign: Encryption["sign"] = sendPrivateKey ? (data) => signMessage(data, sendPrivateKey, true).then( encryptedMessage.toString, ) : bypassSign; return { sign, verify }; }; export const asChannel = async ( socket: WebSocket, encryption?: ChannelEncryption, ): Promise> => { const { sign, verify } = useChannelEncryption(encryption); const ready = new Event(); const recv = new Queue(); const closed = new Event(); socket.addEventListener("open", () => { ready.set(); }); socket.addEventListener("close", () => { closed.set(); }); socket.addEventListener("message", (event) => { recv.push(event.data); }); socket.addEventListener("error", (event) => { console.log("error", event); }); await Promise.race([ready.wait(), closed.wait()]); return { send: async (data: Send) => { const stringifiedData = JSON.stringify(data); await sign(stringifiedData).then((signed) => { if (!closed.is_set()) { socket.send(signed); } }); }, recv: async () => { const received = await recv.pop(); const { isValid, data } = await verify(received?.toString()); if (!isValid) { throw new Error( `channel encryption does not match.\n Data: ${data}\n Received: ${received.toString()}`, ); } if (data === "undefined") { return undefined; } return data ? JSON.parse(data) : {}; }, closed, }; }; /** * Adds durable encryption layer to the sent messages. */ export const asEncryptedChannel = async ( socket: WebSocket, ): Promise> => { return asChannel(socket, await channelEncryption()); }; /** * Adds a layer of verification for received messages */ export const asVerifiedChannel = async ( socket: WebSocket, key: PromiseOrValue, ): Promise> => { return asChannel(socket, { recvPublicKey: await importJWK(await key, ["verify"]), }); };