Add language assistant features and improve encryption handling: Implement a new route and controller method for sending messages to the language assistant, enhancing user interaction within lessons. Update the encryption utility to support both base64 and hex formats for better compatibility with existing data. Enhance localization files to include new terms related to the language assistant in English, German, and Spanish, improving user experience across languages.

backend/utils/encryption.js

@@ -14,19 +14,32 @@ export const generateIv = () => {
 
 export const encrypt = (text) => {
     const cipher = crypto.createCipheriv(algorithm, key, null);
-    let encrypted = cipher.update(text, 'utf8', 'hex'); 
-    encrypted += cipher.final('hex');
+    let encrypted = cipher.update(text, 'utf8', 'base64');
+    encrypted += cipher.final('base64');
     return encrypted;
 };
 
 export const decrypt = (text) => {
+    if (!text) {
+        return null;
+    }
+
+    const input = String(text);
     try {
         const decipher = crypto.createDecipheriv(algorithm, key, null);
-        let decrypted = decipher.update(text, 'hex', 'utf8'); 
+        let decrypted = decipher.update(input, 'base64', 'utf8');
         decrypted += decipher.final('utf8');
         return decrypted;
-    } catch (error) {
-        console.log(error);
-        return null;    
+    } catch (base64Error) {
+        try {
+            // Rueckwaertskompatibel fuer bereits gespeicherte Hex-Werte.
+            const decipher = crypto.createDecipheriv(algorithm, key, null);
+            let decrypted = decipher.update(input, 'hex', 'utf8');
+            decrypted += decipher.final('utf8');
+            return decrypted;
+        } catch (hexError) {
+            console.log(hexError);
+            return null;
+        }
     }
 };