Add zlib compression with fflate

Author: vishnumad

packages/client/package.json

@@ -25,7 +25,7 @@
   "scripts": {
     "test": "jest",
     "test:coverage": "yarn test:unit && open coverage/lcov-report/index.html",
-    "prebuild": "rm -rf ./build && node -p \"'export const LIB_VERSION = \\'' + require('./package.json').version + '\\';'\" > src/version.ts",
+    "prebuild": "rm -rf ./dist && node -p \"'export const LIB_VERSION = \\'' + require('./package.json').version + '\\';'\" > src/version.ts",
     "build": "tsc -p ./tsconfig.build.json && tsc-alias",
     "dev": "tsc --watch & nodemon --watch dist --delay 1 --exec tsc-alias",
     "typecheck": "tsc --noEmit",
@@ -35,7 +35,8 @@
     "@noble/ciphers": "^0.5.3",
     "@noble/curves": "^1.4.2",
     "@noble/hashes": "^1.4.0",
-    "eventemitter3": "^5.0.1"
+    "eventemitter3": "^5.0.1",
+    "fflate": "^0.8.2"
   },
   "peerDependencies": {
     "@react-native-async-storage/async-storage": "*",
@@ -81,4 +82,4 @@
     "tslib": "^2.6.0",
     "typescript": "^5.1.6"
   }
-}
+}

packages/client/src/core/cipher/cipher.test.ts

@@ -1,3 +1,5 @@
+import { unzlibSync, zlibSync } from 'fflate';
+
 import {
   decrypt,
   decryptContent,
@@ -13,10 +15,12 @@ import { hexStringToUint8Array, uint8ArrayToHex } from ':core/type/util';
 
 async function webEncrypt(sharedSecret: CryptoKey, plainText: string): Promise<EncryptedData> {
   const iv = crypto.getRandomValues(new Uint8Array(12));
+  const plainTextBytes = new TextEncoder().encode(plainText);
+  const compressedBytes = zlibSync(plainTextBytes);
   const cipherText = await crypto.subtle.encrypt(
     { name: 'AES-GCM', iv },
     sharedSecret,
-    new TextEncoder().encode(plainText)
+    compressedBytes
   );
 
   return { iv: new Uint8Array(iv), cipherText: new Uint8Array(cipherText) };
@@ -26,9 +30,13 @@ async function webDecrypt(
   sharedSecret: CryptoKey,
   { iv, cipherText }: EncryptedData
 ): Promise<string> {
-  const plainText = await crypto.subtle.decrypt({ name: 'AES-GCM', iv }, sharedSecret, cipherText);
-
-  return new TextDecoder().decode(plainText);
+  const compressedBytes = await crypto.subtle.decrypt(
+    { name: 'AES-GCM', iv },
+    sharedSecret,
+    cipherText
+  );
+  const decompressedBytes = unzlibSync(Buffer.from(compressedBytes));
+  return new TextDecoder().decode(decompressedBytes);
 }
 
 function getFormat(keyType: 'public' | 'private') {

packages/client/src/core/cipher/cipher.ts

@@ -2,6 +2,7 @@ import { gcm } from '@noble/ciphers/aes';
 import { randomBytes } from '@noble/ciphers/webcrypto';
 import { secp256r1 } from '@noble/curves/p256';
 import { Buffer } from 'buffer';
+import { unzlibSync, zlibSync } from 'fflate';
 
 import { CryptoKey, CryptoKeyPair } from './types';
 import { EncryptedData, RPCRequest, RPCResponse } from ':core/message';
@@ -61,7 +62,8 @@ export async function encrypt(sharedSecret: CryptoKey, plainText: string): Promi
   const iv = randomBytes(12);
   const stream = gcm(sharedSecret._key, iv);
   const plainTextBytes = new Uint8Array(Buffer.from(plainText, 'utf8'));
-  const cipherText = stream.encrypt(plainTextBytes);
+  const compressedBytes = zlibSync(plainTextBytes);
+  const cipherText = stream.encrypt(compressedBytes);
 
   return {
     iv,
@@ -74,8 +76,8 @@ export async function decrypt(
   { iv, cipherText }: EncryptedData
 ): Promise<string> {
   const stream = gcm(new Uint8Array(sharedSecret._key), new Uint8Array(iv));
-  const plainTextBytes = stream.decrypt(new Uint8Array(cipherText));
-
+  const compressedBytes = stream.decrypt(new Uint8Array(cipherText));
+  const plainTextBytes = unzlibSync(compressedBytes);
   return Buffer.from(plainTextBytes).toString('utf8');
 }
 

yarn.lock

@@ -2069,6 +2069,7 @@ __metadata:
     eslint-plugin-unused-imports: "npm:^3.0.0"
     eventemitter3: "npm:^5.0.1"
     expo-web-browser: "npm:^13.0.3"
+    fflate: "npm:^0.8.2"
     jest: "npm:^27.5.1"
     jest-chrome: "npm:^0.7.2"
     jest-websocket-mock: "npm:^2.4.0"
@@ -4623,6 +4624,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"fflate@npm:^0.8.2":
+  version: 0.8.2
+  resolution: "fflate@npm:0.8.2"
+  checksum: 10c0/03448d630c0a583abea594835a9fdb2aaf7d67787055a761515bf4ed862913cfd693b4c4ffd5c3f3b355a70cf1e19033e9ae5aedcca103188aaff91b8bd6e293
+  languageName: node
+  linkType: hard
+
 "file-entry-cache@npm:^6.0.1":
   version: 6.0.1
   resolution: "file-entry-cache@npm:6.0.1"