PHP中如何使用信箱驗證來防止使用者盜用其他人帳號登入？

<form action="register.php" method="POST">
  <label for="email">邮箱：</label>
  <input type="email" name="email" id="email" required>
  <button type="submit">注册</button>
</form>

<?php
// 随机生成验证码
$verificationCode = mt_rand(100000, 999999);

// 将验证码保存至数据库，关联邮箱和验证码
saveVerificationCodeToDatabase($email, $verificationCode);

// 发送验证邮件
$subject = "邮箱验证";
$message = "您的验证码是：" . $verificationCode;
$headers = "From: admin@example.com";

mail($email, $subject, $message, $headers);
?>

<?php
$codeFromUser = $_GET['code']; // 用户点击验证码链接或输入的验证码

// 根据邮箱从数据库中获取保存的验证码
$verificationCodeFromDatabase = getVerificationCodeFromDatabase($email);

if ($verificationCodeFromDatabase == $codeFromUser) {
  // 验证通过，将用户标记为已验证状态
  setVerifiedStatus($email);
  echo "验证成功！";
} else {
  echo "验证失败！";
}
?>

<form action="login.php" method="POST">
  <label for="email">邮箱：</label>
  <input type="email" name="email" id="email" required>
  <label for="password">密码：</label>
  <input type="password" name="password" id="password" required>
  <button type="submit">登录</button>
</form>

<?php
// 验证用户是否已通过邮箱验证
if (isVerified($email)) {
  // 执行登录操作
  if (login($email, $password)) {
    echo "登录成功！";
  } else {
    echo "用户名或密码错误！";
  }
} else {
  echo "请先完成邮箱验证！";
}
?>