Encrypt message data at rest

backend/src/utils/crypt.test.ts

@@ -0,0 +1,10 @@
+import test from "ava";
+
+import { encrypt, decrypt } from "./crypt";
+
+test("encrypt() followed by decrypt()", t => {
+  const original = "banana 123 👀 💕"; // Includes emojis to verify utf8 stuff works
+  const encrypted = encrypt(original);
+  const decrypted = decrypt(encrypted);
+  t.is(decrypted, original);
+});