什么是**时差攻击**？

假设攻击者试图猜出用户名与密码。

他们发送用户名为 `johndoe`，密码为 `love123`  的请求。

然后，Python 代码执行如下操作：

```Python
if "johndoe" == "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

Let's imagine some attackers are trying to guess the username and password.

And they send a request with a username `johndoe` and a password `love123`.

Then the Python code in your application would be equivalent to something like:

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

Vamos imaginar que alguns invasores estão tentando adivinhar o usuário e a senha.

E eles enviam uma requisição com um usuário `johndoe` e uma senha `love123`.

Então o código Python em sua aplicação seria equivalente a algo como:

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

& 👫 📨 📨 ⏮️ 🆔 `johndoe` & 🔐 `love123`.

⤴️ 🐍 📟 👆 🈸 🔜 🌓 🕳 💖:

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

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

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

& 👆 🈸 📟 🔨 🕳 💖:

Und sie senden eine Anfrage mit dem Benutzernamen `johndoe` und dem Passwort `love123`.

Dann würde der Python-Code in Ihrer Anwendung etwa so aussehen:

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