Fix symmetric encryption internal types (#726)

CHANGELOG.md

@@ -1,8 +1,9 @@
 
 # Changelog
 
-## 0.4.1 ~ 0.4.2
+## 0.4.1 ~ 0.4.3
 
+- Fix symmetric encryption internal types
 - Add XChacha20 as an optional encryption backend
 - Add configuration for more compatibility
 - Bump dependencies

package.json

@@ -11,7 +11,7 @@
     "type": "git",
     "url": "https://github.com/ecies/js.git"
   },
-  "version": "0.4.2",
+  "version": "0.4.3",
   "engines": {
     "node": ">=16.0.0"
   },

src/utils/symmetric.ts

@@ -8,85 +8,113 @@ import { createCipheriv, createDecipheriv } from "crypto";
 import { NonceLength, symmetricAlgorithm, symmetricNonceLength } from "../config";
 import { AEAD_TAG_LENGTH, XCHACHA20_NONCE_LENGTH } from "../consts";
 
-function _aesEncrypt(key: Buffer, plainText: Buffer, nonceLength: NonceLength): Buffer {
+function _aesEncrypt(
+  key: Uint8Array,
+  plainText: Uint8Array,
+  nonceLength: NonceLength
+): Uint8Array {
   const nonce = randomBytes(nonceLength);
   const cipher = createCipheriv("aes-256-gcm", key, nonce);
-  const encrypted = Buffer.concat([cipher.update(plainText), cipher.final()]);
+
+  const updated = cipher.update(plainText);
+  const finalized = cipher.final();
   const tag = cipher.getAuthTag();
-  return Buffer.concat([nonce, tag, encrypted]);
+
+  const payload = new Uint8Array(
+    nonce.length + tag.length + updated.length + finalized.length
+  );
+  payload.set(nonce);
+  payload.set(tag, nonce.length);
+  payload.set(updated, nonce.length + tag.length);
+  payload.set(finalized, nonce.length + tag.length + updated.length);
+  return payload;
 }
 
 function _aesDecrypt(
-  key: Buffer,
-  cipherText: Buffer,
+  key: Uint8Array,
+  cipherText: Uint8Array,
   nonceLength: NonceLength
-): Buffer {
+): Uint8Array {
   const nonceTagLength = nonceLength + AEAD_TAG_LENGTH;
   const nonce = cipherText.subarray(0, nonceLength);
   const tag = cipherText.subarray(nonceLength, nonceTagLength);
   const ciphered = cipherText.subarray(nonceTagLength);
   const decipher = createDecipheriv("aes-256-gcm", key, nonce);
   decipher.setAuthTag(tag);
-  return Buffer.concat([decipher.update(ciphered), decipher.final()]);
+
+  const updated = decipher.update(ciphered);
+  const finalized = decipher.final();
+
+  const payload = new Uint8Array(updated.length + finalized.length);
+  payload.set(updated);
+  payload.set(finalized, updated.length);
+  return payload;
 }
 
 function _encrypt(
   func: (key: Uint8Array, nonce: Uint8Array, AAD?: Uint8Array) => Cipher,
-  key: Buffer,
-  plainText: Buffer,
+  key: Uint8Array,
+  plainText: Uint8Array,
   nonceLength: number
-) {
+): Uint8Array {
   const nonce = randomBytes(nonceLength);
   const cipher = func(key, nonce);
-  const ciphered = cipher.encrypt(plainText);
+  const ciphered = cipher.encrypt(plainText); // TAG + encrypted
+
   const encrypted = ciphered.subarray(0, ciphered.length - AEAD_TAG_LENGTH);
   const tag = ciphered.subarray(-AEAD_TAG_LENGTH);
-  return Buffer.concat([nonce, tag, encrypted]);
+
+  const payload = new Uint8Array(nonce.length + tag.length + encrypted.length);
+  payload.set(nonce);
+  payload.set(tag, nonce.length);
+  payload.set(encrypted, nonce.length + tag.length);
+  return payload;
 }
 
 function _decrypt(
   func: (key: Uint8Array, nonce: Uint8Array, AAD?: Uint8Array) => Cipher,
-  key: Buffer,
-  cipherText: Buffer,
+  key: Uint8Array,
+  cipherText: Uint8Array,
   nonceLength: number
-) {
+): Uint8Array {
   const nonceTagLength = nonceLength + AEAD_TAG_LENGTH;
   const nonce = cipherText.subarray(0, nonceLength);
   const tag = cipherText.subarray(nonceLength, nonceTagLength);
-  const ciphered = cipherText.subarray(nonceTagLength);
+  const encrypted = cipherText.subarray(nonceTagLength);
+
+  const decipher = func(key, Uint8Array.from(nonce)); // to reset byteOffset
 
-  const decipher = func(key, nonce);
-  const res = new Uint8Array(AEAD_TAG_LENGTH + ciphered.length);
-  res.set(ciphered);
-  res.set(tag, ciphered.length);
-  return Buffer.from(decipher.decrypt(res));
+  const ciphered = new Uint8Array(encrypted.length + AEAD_TAG_LENGTH);
+  ciphered.set(encrypted);
+  ciphered.set(tag, encrypted.length);
+  return decipher.decrypt(ciphered);
 }
 
-export function aesEncrypt(key: Buffer, plainText: Buffer): Buffer {
+export function aesEncrypt(key: Uint8Array, plainText: Uint8Array): Buffer {
   // TODO: Rename to symEncrypt
   const algorithm = symmetricAlgorithm();
   if (algorithm === "aes-256-gcm") {
-    return _aesEncrypt(key, plainText, symmetricNonceLength());
+    return Buffer.from(_aesEncrypt(key, plainText, symmetricNonceLength()));
   } else if (algorithm === "xchacha20") {
-    return _encrypt(xchacha20, key, plainText, XCHACHA20_NONCE_LENGTH);
+    return Buffer.from(_encrypt(xchacha20, key, plainText, XCHACHA20_NONCE_LENGTH));
   } else {
     throw new Error("Not implemented");
   }
 }
 
-export function aesDecrypt(key: Buffer, cipherText: Buffer): Buffer {
+export function aesDecrypt(key: Uint8Array, cipherText: Uint8Array): Buffer {
   // TODO: Rename to symDecrypt
   const algorithm = symmetricAlgorithm();
   if (algorithm === "aes-256-gcm") {
-    return _aesDecrypt(key, cipherText, symmetricNonceLength());
+    return Buffer.from(_aesDecrypt(key, cipherText, symmetricNonceLength()));
   } else if (algorithm === "xchacha20") {
-    return _decrypt(xchacha20, key, cipherText, XCHACHA20_NONCE_LENGTH);
+    return Buffer.from(_decrypt(xchacha20, key, cipherText, XCHACHA20_NONCE_LENGTH));
   } else {
     throw new Error("Not implemented");
   }
 }
 
-export function deriveKey(master: Buffer) {
+export function deriveKey(master: Uint8Array): Buffer {
   // 32 bytes shared secret for aes and chacha20
   return Buffer.from(hkdf(sha256, master, undefined, undefined, 32));
 }

tests/crypt.test.ts

@@ -1,6 +1,7 @@
 import { ECIES_CONFIG } from "../src/config";
 import { decrypt, encrypt } from "../src/index";
 import { PrivateKey, PublicKey } from "../src/keys";
+import { decodeHex } from "../src/utils";
 
 const TEXT = "helloworld🌍";
 
@@ -19,19 +20,13 @@ function checkHex(sk: PrivateKey) {
 }
 
 describe("test encrypt and decrypt", () => {
-  it("tests encrypt/decrypt buffer", () => {
+  it("tests encrypt/decrypt", () => {
     const prv1 = new PrivateKey();
     check(prv1);
-
-    const prv2 = new PrivateKey();
-    check(prv2, true);
-  });
-
-  it("tests encrypt/decrypt hex", () => {
-    const prv1 = new PrivateKey();
     checkHex(prv1);
 
     const prv2 = new PrivateKey();
+    check(prv2, true);
     checkHex(prv2);
   });
 
@@ -46,12 +41,54 @@ describe("test encrypt and decrypt", () => {
     expect(decrypt(sk.toHex(), enc).toString()).toBe(TEXT);
   });
 
-  it("tests ephemeral key config", () => {
+  it("tests config can be changed", () => {
     ECIES_CONFIG.isEphemeralKeyCompressed = true;
+    ECIES_CONFIG.isHkdfKeyCompressed = true;
 
     const prv1 = new PrivateKey();
     check(prv1);
 
+    const prv2 = new PrivateKey();
+    checkHex(prv2);
+
     ECIES_CONFIG.isEphemeralKeyCompressed = false;
+    ECIES_CONFIG.isHkdfKeyCompressed = false;
+  });
+
+  it("tests encrypt/decrypt chacha", () => {
+    ECIES_CONFIG.symmetricAlgorithm = "xchacha20";
+    ECIES_CONFIG.isEphemeralKeyCompressed = true;
+
+    const prv1 = new PrivateKey();
+    check(prv1);
+
+    const prv2 = new PrivateKey();
+    checkHex(prv2);
+
+    ECIES_CONFIG.symmetricAlgorithm = "aes-256-gcm";
+    ECIES_CONFIG.isEphemeralKeyCompressed = false;
+  });
+
+  it("tests known sk pk chacha", () => {
+    ECIES_CONFIG.symmetricAlgorithm = "xchacha20";
+
+    const sk = PrivateKey.fromHex(
+      "0000000000000000000000000000000000000000000000000000000000000002"
+    );
+    const pk = PublicKey.fromHex(
+      "02c6047f9441ed7d6d3045406e95c07cd85c778e4b8cef3ca7abac09b95c709ee5"
+    );
+    const enc = encrypt(pk.toHex(), Buffer.from(TEXT));
+    expect(decrypt(sk.toHex(), enc).toString()).toBe(TEXT);
+
+    const known_enc = decodeHex(
+      "0x04e314abc14398e07974cd50221b682ed5f0629e977345fc03e2047208ee6e279f" +
+        "fb2a6942878d3798c968d89e59c999e082b0598d1b641968c48c8d47c570210d0a" +
+        "b1ade95eeca1080c45366562f9983faa423ee3fd3260757053d5843c5f453e1ee6" +
+        "bb955c8e5d4aee8572139357a091909357a8931b"
+    );
+    expect(decrypt(sk.toHex(), known_enc).toString()).toBe(TEXT);
+
+    ECIES_CONFIG.symmetricAlgorithm = "aes-256-gcm";
   });
 });