diff --git a/backend/package.json b/backend/package.json
index 28162e3..fb1a3c5 100644
--- a/backend/package.json
+++ b/backend/package.json
@@ -1,6 +1,6 @@
 {
   "name": "backend",
-  "comment": "added by heartbeat"
+  "comment": "added by heartbeat",
   "version": "1.0.0",
   "description": "",
   "main": "index.js",
diff --git a/backend/src/services/encryption.test.js b/backend/src/services/encryption.test.js
new file mode 100644
index 0000000..ce20df1
--- /dev/null
+++ b/backend/src/services/encryption.test.js
@@ -0,0 +1,23 @@
+import { encryptText, decryptText } from './encryption.js';
+
+const TEST_KEY = 'YixWi1MYh77NMEQYSJZR+2IsVotTGIe+zTBEGEiWUfs='; // 32 bytes base64
+
+process.env.DATA_ENCRYPTION_KEY = TEST_KEY;
+
+const run = async () => {
+  const plain = 'Hello, World! 123';
+  const encrypted = encryptText(plain);
+  const decrypted = decryptText(encrypted);
+
+  if (decrypted !== plain) {
+    console.error('Decryption mismatch:', { plain, decrypted });
+    process.exit(1);
+  }
+
+  console.log('Encryption tests passed');
+};
+
+run().catch((err) => {
+  console.error('Encryption tests failed:', err.message);
+  process.exit(1);
+});
\ No newline at end of file