Update app.py

app.py

@@ -66,24 +66,44 @@ def test_endpoint():
 @app.route("/sign", methods=["POST"])
 def sign_payload():
     """
-    Expects JSON body with a single field `payload` (the string you need to sign).
-    Returns base64-encoded RSA-SHA256 signature.
+    Generate RSA-SHA256 signature for a given string payload.
+    Body: { "payload": "string-to-sign" }
+    Returns: { "signature": "base64_signature" }
     """
     try:
+        import rsa, base64
+
         data = request.get_json(force=True)
         payload = data.get("payload", "")
+
         if not payload:
             return jsonify({"error": "Missing 'payload' field"}), 400
 
-        # Load private key
-        priv_key = rsa.PrivateKey.load_pkcs1(PRIVATE_KEY.encode())
+        # 🔒 Clean and load your PEM private key properly
+        key_data = PRIVATE_KEY.encode()
+        try:
+            priv_key = rsa.PrivateKey.load_pkcs1(key_data)
+        except Exception:
+            # Some keys use PKCS#8 format, handle conversion
+            from Crypto.PublicKey import RSA as CryptoRSA
+            from Crypto.Signature import pkcs1_15
+            from Crypto.Hash import SHA256
+            import base64
 
-        # Create signature
+            # Fallback for PKCS#8 keys
+            crypto_key = CryptoRSA.import_key(PRIVATE_KEY)
+            h = SHA256.new(payload.encode())
+            signature = pkcs1_15.new(crypto_key).sign(h)
+            signature_b64 = base64.b64encode(signature).decode()
+            return jsonify({"signature": signature_b64}), 200
+
+        # ✅ Sign using rsa library (PKCS#1 v1.5)
         signature = rsa.sign(payload.encode(), priv_key, 'SHA-256')
         signature_b64 = base64.b64encode(signature).decode()
 
-        print("✅ Generated signature for payload:", payload)
+        print("✅ Generated signature for:", payload)
         return jsonify({"signature": signature_b64}), 200
+
     except Exception as e:
         print("🔥 Error generating signature:", str(e))
         return jsonify({"error": str(e)}), 500