implement substition

webservice/crypto.py

@@ -9,3 +9,7 @@ def hash_password(password: str) -> str:
 def generate_new_token(length: int = 32) -> str:
     """Generiert einen neuen sicheren Token."""
     return secrets.token_hex(length)  # Erzeugt einen sicheren Token
+
+def substitute_string_reverse(s: str, alphabet: str, key: str) -> str:
+    reverse_map = {k: a for a, k in zip(alphabet, key)}
+    return "".join(reverse_map.get(ch.upper(), ch) for ch in s)

webservice/models.py

@@ -56,3 +56,11 @@ class SensorData(SQLModel, table=True):
 
 class EncryptedPayload(BaseModel):
     data: str
+
+class SensorDataEncryptedIn(BaseModel):
+    timestamp: str = Field(...)
+    temperature: Optional[str] = None
+    humidity: Optional[str] = None
+    pressure: Optional[str] = None
+    voc: Optional[str] = None
+    gas: Optional[str] = None

webservice/webservice.py

@@ -6,34 +6,24 @@ from fastapi import FastAPI, Depends, HTTPException, Header, Body, Query
 from fastapi.middleware.cors import CORSMiddleware
 from sqlmodel import Session
 from dbfunctions import List, Optional, get_db, save_sensor_data, get_client_id_by_name, validate_token_with_access, engine, save_token_to_db, get_recent_sensor_data, get_all_clients
-from models import EncryptedPayload, SensorDataIn, SensorData, MessageOnly, User, Client, ClientCreate, TokenResponse, Session as SessionModel
+from models import SensorDataIn, SensorData, SensorDataEncryptedIn, MessageOnly, User, Client, ClientCreate, TokenResponse, Session as SessionModel
 from datetime import datetime, timedelta
-from crypto import hash_password, generate_new_token
+from crypto import hash_password, generate_new_token, substitute_string_reverse
-from Crypto.Cipher import AES
+from os import getenv as env
-import base64
-
-
-AES_KEY = bytes([0x27, 0x9A, 0xB3, 0x11, 0xE7, 0x3D, 0xCC, 0x88,
-                 0x55, 0x10, 0x9F, 0x4A, 0x6B, 0x1D, 0x20, 0x2F])
-
-def decrypt_base64_aes128(encrypted_b64: str) -> str:
-    encrypted_bytes = base64.b64decode(encrypted_b64)
-    cipher = AES.new(AES_KEY, AES.MODE_ECB)
-    decrypted = cipher.decrypt(encrypted_bytes)
-
-    # Entferne Null-Byte-Padding (falls verwendet)
-    return decrypted.rstrip(b"\0").decode("utf-8")
 
+############# SUBSTITION #############
+ALPHABET = "ABCDEFGHIJKLMONPQRSTUVWXYZ012345689-:."
+KEY      = env("CRYPTO_SUBSTITION_KEY")
 
 ################ API ################
 app = FastAPI(
     title="BBZW-Horizon",
     description="BBZW-Horizon ist ein Tool, welches entwickelt wurde, um durch die Erfassung und Auswertung von Luftqualitätsmesswerten die Luftqualität in den Schulzimmern des BBZW Sursee zu verbessern. Bei dieser API handelt es sich um die Kommunikationsschnittstelle, zwischen den Arduinos, welche mit Sensoren die Daten erfassen und an die API senden. Diese API speichert die Daten dann in der Datenbank, damit diese durch das Frontend abgerufen und visualisiert werden können.",
     summary="Die BBZW-Horizon API dient als Kommunikationsschnittstelle, um Luftqualitätsmesswerte von Arduinos, die mit Sensoren ausgestattet sind, zu erfassen",
-    version="0.0.6"
+    version="0.0.7"
 )
 
-# CORS
+############### CORS ################
 origins = [
     "*",
 ]
@@ -83,6 +73,49 @@ async def saveNewSensorData(
     except Exception as error:
         raise HTTPException(status_code=500, detail=str(error))
     
+@app.post("/sensors/push-data/secure", response_model=MessageOnly, tags=["sensors"])
+async def saveNewSensorDataSecure(
+    client: str,
+    data: SensorDataEncryptedIn,
+    db: Session = Depends(get_db),
+    auth: bool = Depends(authenticate_user)
+):
+    # Client-ID bestimmen
+    client_id = get_client_id_by_name(db, client)
+    if client_id is None:
+        raise HTTPException(status_code=404, detail="Client not found")
+
+    # Entschlüssle Timestamp
+    decrypted_timestamp_str = substitute_string_reverse(data.timestamp, ALPHABET, KEY)
+    try:
+        timestamp = datetime.fromisoformat(decrypted_timestamp_str)
+    except ValueError:
+        raise HTTPException(status_code=400, detail="Invalid encrypted timestamp format")
+
+    # Hilfsfunktion zum Entschlüsseln Zahlenwerte
+    def decrypt_value(enc_val: Optional[str]) -> Optional[float]:
+        if enc_val is None:
+            return None
+        decrypted_str = substitute_string_reverse(enc_val, ALPHABET, KEY)
+        try:
+            return float(decrypted_str)
+        except ValueError:
+            raise HTTPException(status_code=400, detail=f"Invalid encrypted sensor value: {enc_val}")
+
+    sensor_data = SensorData(
+        timestamp=timestamp,
+        temperature=decrypt_value(data.temperature),
+        humidity=decrypt_value(data.humidity),
+        pressure=decrypt_value(data.pressure),
+        voc=decrypt_value(data.voc),
+        gas=decrypt_value(data.gas),
+        clientid=client_id
+    )
+
+    save_sensor_data(db, sensor_data)
+
+    return MessageOnly(message="Decrypted sensor data saved successfully.")
+    
 @app.post("/user/new-session", response_model=TokenResponse, tags=["auth"])
 async def generate_token(
     username: str = Body(...),
@@ -205,31 +238,3 @@ async def create_client(
     db.refresh(new_client)
 
     return MessageOnly(message="Client created successfully.")
-
-
-@app.post("/sensors/push-encrypted", response_model=MessageOnly, tags=["sensors"])
-async def save_encrypted_sensor_data(
-    client: str,
-    encrypted: EncryptedPayload,
-    db: Session = Depends(get_db),
-    auth: bool = Depends(authenticate_user)
-):
-    try:
-        decrypted_json = decrypt_base64_aes128(encrypted.data)
-
-        # Parse JSON zu Pydantic-Modell
-        data = SensorDataIn.model_validate_json(decrypted_json)
-
-        # Client-ID abrufen
-        client_id = get_client_id_by_name(db, client)
-        if client_id is None:
-            raise HTTPException(status_code=404, detail="Client not found")
-
-        sensor_data = SensorData(**data.dict())
-        sensor_data.clientid = client_id
-
-        save_sensor_data(db, sensor_data)
-
-        return MessageOnly(message="Encrypted sensor data saved successfully.")
-    except Exception as e:
-        raise HTTPException(status_code=500, detail=f"Error decoding or saving: {str(e)}")