aead-stream/dist/webcrypto/web-encrypt.js

Authenticated encryption on arbitrary large files

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.webEncrypt = void 0;
const chunkify_1 = require("../chunkify");
const util_1 = require("./util");
const profiles = { "AES-GCM": 1 };
const defaultOptions = {
    profile: "AES-GCM",
    chunkSize: 64 * 1024, // 64K
};
async function* webEncrypt(key, plaintext, options = defaultOptions) {
    var _a;
    // magic number
    yield new TextEncoder().encode("aead");
    switch ((_a = options.profile) !== null && _a !== void 0 ? _a : "AES-GCM") {
        case "AES-GCM":
            yield* aesGcmEncrypt(key, plaintext, options);
            return;
        default:
            throw new Error("unsupported profile: " + options.profile);
    }
}
exports.webEncrypt = webEncrypt;
async function* aesGcmEncrypt(key, plaintext, options = defaultOptions) {
    var _a;
    const nonceLength = 12;
    const authTagLength = 16;
    const cipherTextChunkSize = (_a = options.chunkSize) !== null && _a !== void 0 ? _a : defaultOptions.chunkSize;
    const chunkSize = cipherTextChunkSize - nonceLength - authTagLength;
    yield Uint8Array.of(profiles["AES-GCM"], ...(0, util_1.encodeUint32)(cipherTextChunkSize));
    const crypto = await (0, util_1.webcrypto)();
    let chunkIndex = 0;
    for await (const chunk of (0, chunkify_1.chunkify)(chunkSize, plaintext)) {
        const nonce = new Uint8Array(nonceLength);
        crypto.getRandomValues(nonce);
        let aad = (0, util_1.encodeUint32)(chunkIndex++);
        if (options.associatedData) {
            aad = (0, util_1.concat)(aad, options.associatedData);
        }
        const ciphertext = await crypto.subtle.encrypt({
            name: "AES-GCM",
            iv: nonce,
            additionalData: aad,
            tagLength: authTagLength * 8,
        }, key, chunk);
        yield (0, util_1.concat)(nonce, new Uint8Array(ciphertext));
    }
}