From 030a85199f94073376c3a4f55f06db50fbcb889d Mon Sep 17 00:00:00 2001
From: Bryan Housel <bryan@mapbox.com>
Date: Thu, 13 Feb 2020 13:11:34 -0500
Subject: [PATCH] Add support for AES encrypt/decrypting sensitive values
 (closes #7355)

---
 modules/util/aes.js   | 28 ++++++++++++++++++++++++
 modules/util/index.js |  3 +++
 package.json          |  1 +
 test/index.html       |  1 +
 test/spec/util/aes.js | 50 +++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 83 insertions(+)
 create mode 100644 modules/util/aes.js
 create mode 100644 test/spec/util/aes.js

diff --git a/modules/util/aes.js b/modules/util/aes.js
new file mode 100644
index 000000000..ce40a73ed
--- /dev/null
+++ b/modules/util/aes.js
@@ -0,0 +1,28 @@
+import aesjs from 'aes-js';
+
+// See https://github.com/ricmoo/aes-js
+// We can use keys that are 128 bits (16 bytes), 192 bits (24 bytes) or 256 bits (32 bytes).
+// To generate a random key:  window.crypto.getRandomValues(new Uint8Array(16));
+
+// This default signing key is built into iD and can be used to mask/unmask sensitive values.
+const DEFAULT_128 = [250, 157, 60, 79, 142, 134, 229, 129, 138, 126, 210, 129, 29, 71, 160, 208];
+
+
+export function utilAesEncrypt(text, key) {
+  key = key || DEFAULT_128;
+  const textBytes = aesjs.utils.utf8.toBytes(text);
+  const aesCtr = new aesjs.ModeOfOperation.ctr(key);
+  const encryptedBytes = aesCtr.encrypt(textBytes);
+  const encryptedHex = aesjs.utils.hex.fromBytes(encryptedBytes);
+  return encryptedHex;
+}
+
+
+export function utilAesDecrypt(encryptedHex, key) {
+  key = key || DEFAULT_128;
+  const encryptedBytes = aesjs.utils.hex.toBytes(encryptedHex);
+  const aesCtr = new aesjs.ModeOfOperation.ctr(key);
+  const decryptedBytes = aesCtr.decrypt(encryptedBytes);
+  const text = aesjs.utils.utf8.fromBytes(decryptedBytes);
+  return text;
+}
diff --git a/modules/util/index.js b/modules/util/index.js
index ce1e2ca16..b6a5f8507 100644
--- a/modules/util/index.js
+++ b/modules/util/index.js
@@ -1,3 +1,6 @@
+export { utilAesEncrypt } from './aes';
+export { utilAesDecrypt } from './aes';
+
 export { utilArrayChunk } from './array';
 export { utilArrayDifference } from './array';
 export { utilArrayFlatten } from './array';
diff --git a/package.json b/package.json
index 222553258..948f24197 100644
--- a/package.json
+++ b/package.json
@@ -46,6 +46,7 @@
     "@mapbox/vector-tile": "^1.3.1",
     "@turf/bbox-clip": "^6.0.0",
     "abortcontroller-polyfill": "^1.4.0",
+    "aes-js": "^3.1.2",
     "alif-toolkit": "^1.2.6",
     "browser-polyfills": "~1.5.0",
     "diacritics": "1.3.0",
diff --git a/test/index.html b/test/index.html
index 8ef4f63b8..35498a23e 100644
--- a/test/index.html
+++ b/test/index.html
@@ -141,6 +141,7 @@
       'spec/ui/fields/localized.js',
       'spec/ui/fields/wikipedia.js',
 
+      'spec/util/aes.js',
       'spec/util/array.js',
       'spec/util/clean_tags.js',
       'spec/util/keybinding.js',
diff --git a/test/spec/util/aes.js b/test/spec/util/aes.js
new file mode 100644
index 000000000..ce1cac024
--- /dev/null
+++ b/test/spec/util/aes.js
@@ -0,0 +1,50 @@
+describe('iD.utilAes', function() {
+
+    it('encrypting and decrypting nothing yields nothing', function() {
+        expect(iD.utilAesEncrypt('')).to.eql('');
+        expect(iD.utilAesDecrypt('')).to.eql('');
+    });
+
+    it('encrypts and decrypts with default key', function() {
+        var text = 'Hello iD!';
+        var encrypted = '5597506f958c68543c';
+        expect(iD.utilAesEncrypt(text)).to.eql(encrypted);
+        expect(iD.utilAesDecrypt(encrypted)).to.eql(text);
+    });
+
+    it('encrypts and decrypts with a custom 16-bit key', function() {
+        var key = [
+            216, 159, 213, 140, 129,  75,  80, 121,
+             67, 201, 179, 120,  71, 237, 185,  42
+        ];
+        var text = 'Hello iD!';
+        var encrypted = '9ff50e32b04f86640a';
+        expect(iD.utilAesEncrypt(text, key)).to.eql(encrypted);
+        expect(iD.utilAesDecrypt(encrypted, key)).to.eql(text);
+    });
+
+    it('encrypts and decrypts with a custom 24-bit key', function() {
+        var key = [
+            180, 138, 124,  87, 157, 23, 209, 147,
+             64,  65,  68, 206, 212, 79, 215, 114,
+             37,  18, 159,  94, 168, 68, 177, 202
+        ];
+        var text = 'Hello iD!';
+        var encrypted = '85fc05011fa7848417';
+        expect(iD.utilAesEncrypt(text, key)).to.eql(encrypted);
+        expect(iD.utilAesDecrypt(encrypted, key)).to.eql(text);
+    });
+
+    it('encrypts and decrypts with a custom 32-bit key', function() {
+        var key = [
+              4,  48, 130, 253, 213, 139, 96,  178,
+            170, 108, 127, 233, 167, 137, 181,  41,
+            145,  62, 251,   9,  82, 159, 103, 198,
+             63, 200, 158, 104, 188,  77, 193,  16
+        ];
+        var text = 'Hello iD!';
+        var encrypted = '13c21d3dc25165c57c';
+        expect(iD.utilAesEncrypt(text, key)).to.eql(encrypted);
+        expect(iD.utilAesDecrypt(encrypted, key)).to.eql(text);
+    });
+});