Encrypt message data at rest

backend/src/data/encryptedJsonTransformer.ts

@@ -0,0 +1,22 @@
+import { decrypt, encrypt } from "../utils/crypt";
+import { ValueTransformer } from "typeorm";
+
+interface EncryptedJsonTransformer<T> extends ValueTransformer {
+  from(dbValue: any): T;
+  to(entityValue: T): any;
+}
+
+export function createEncryptedJsonTransformer<T>(): EncryptedJsonTransformer<T> {
+  return {
+    // Database -> Entity
+    from(dbValue) {
+      const decrypted = decrypt(dbValue);
+      return JSON.parse(decrypted) as T;
+    },
+
+    // Entity -> Database
+    to(entityValue) {
+      return encrypt(JSON.stringify(entityValue));
+    },
+  };
+}