Então os invasores vão tentar com o usuário `stanleyjobsox` e a senha `love123`.

E a sua aplicação faz algo como:

```Python
if "stanleyjobsox" == "stanleyjobson" and "love123" == "swordfish":
    ...
```

但就在 Python 比较完 `johndoe` 的第一个字母 `j` 与 `stanleyjobson` 的 `s` 时，Python 就已经知道这两个字符串不相同了，它会这么想，**没必要浪费更多时间执行剩余字母的对比计算了**。应用立刻就会返回**错误的用户或密码**。

但接下来，攻击者继续尝试 `stanleyjobsox` 和 密码 `love123`。

应用代码会执行类似下面的操作：

```Python
if "stanleyjobsox" == "stanleyjobson" and "love123" == "swordfish":
    ...
```

此时，Python 要对比 `stanleyjobsox` 与 `stanleyjobson` 中的 `stanleyjobso`，才能知道这两个字符串不一样。因此会多花费几微秒来返回**错误的用户或密码**。

#### 反应时间对攻击者的帮助

```Python
if "johndoe" == "stanleyjobson" and "love123" == "swordfish":
    ...
```

✋️ ▶️️ 🙍 🐍 🔬 🥇 `j` `johndoe` 🥇 `s` `stanleyjobson`, ⚫️ 🔜 📨 `False`, ↩️ ⚫️ ⏪ 💭 👈 📚 2️⃣ 🎻 🚫 🎏, 💭 👈 "📤 🙅‍♂ 💪 🗑 🌅 📊 ⚖ 🎂 🔤". & 👆 🈸 🔜 💬 "❌ 👩‍💻 ⚖️ 🔐".

✋️ ⤴️ 👊 🔄 ⏮️ 🆔 `stanleyjobsox` & 🔐 `love123`.

& 👆 🈸 📟 🔨 🕳 💖:

```Python
if "stanleyjobsox" == "stanleyjobson" and "love123" == "swordfish":

Doch dann versuchen es die Angreifer mit dem Benutzernamen `stanleyjobsox` und dem Passwort `love123`.

Und Ihr Anwendungscode macht etwa Folgendes:

```Python
if "stanleyjobsox" == "stanleyjobson" and "love123" == "swordfish":
    ...
```

But then the attackers try with username `stanleyjobsox` and password `love123`.

And your application code does something like:

```Python
if "stanleyjobsox" == "stanleyjobson" and "love123" == "swordfish":
    ...
```

security = HTTPBasic()


def get_current_username(
    credentials: Annotated[HTTPBasicCredentials, Depends(security)],
):
    current_username_bytes = credentials.username.encode("utf8")
    correct_username_bytes = b"stanleyjobson"
    is_correct_username = secrets.compare_digest(
        current_username_bytes, correct_username_bytes
    )
    current_password_bytes = credentials.password.encode("utf8")
    correct_password_bytes = b"swordfish"

app = FastAPI()

security = HTTPBasic()


def get_current_username(credentials: HTTPBasicCredentials = Depends(security)):
    current_username_bytes = credentials.username.encode("utf8")
    correct_username_bytes = b"stanleyjobson"
    is_correct_username = secrets.compare_digest(
        current_username_bytes, correct_username_bytes
    )
    current_password_bytes = credentials.password.encode("utf8")
    correct_password_bytes = b"swordfish"

security = HTTPBasic()


def get_current_username(
    credentials: Annotated[HTTPBasicCredentials, Depends(security)],
):
    current_username_bytes = credentials.username.encode("utf8")
    correct_username_bytes = b"stanleyjobson"
    is_correct_username = secrets.compare_digest(
        current_username_bytes, correct_username_bytes
    )
    current_password_bytes = credentials.password.encode("utf8")
    correct_password_bytes = b"swordfish"