Let's talk about PHP salt (Salt) implementation function

The security of passwords is something we must consider during development. We can use hash algorithms to ensure the security of passwords. Commonly used hash algorithms include SHA1 and MD5. However, these hashing algorithms are not 100% secure because these algorithms are public and hackers can use various techniques to crack them.

In order to improve the security of passwords, we can use the "salting" method. Salting is adding a random string of characters to a password and then hashing it. In this way, hackers must know the salt value to crack the password, which greatly improves the security of the password.

Next, let’s implement a PHP salting function to protect our password.

Step one: Generate a random salt value

In PHP, you can use the mt_rand() function to generate a random salt value. The first parameter of the mt_rand() function is the starting value, and the second parameter is the ending value. The following code demonstrates how to generate a random salt value of length 8:

$salt = '';
for ($i = 0; $i < 8; $i++) {
    $salt .= chr(mt_rand(33, 126));
}

In the above code, we loop 8 times, each time using the mt_rand() function to generate an ASCII code between 33 and 126 random number between, and then use the chr() function to convert the random number into a character and splice it into the string $salt.

Step 2: Splice the password and salt value

Now that we have obtained a random salt value, we need to concatenate the salt value with the password entered by the user. Then hash it. The following code demonstrates how to concatenate the password and salt value:

$salted_password = $salt . $password;

In the above code, $password is the password entered by the user.

Step 3: Hash the password and salt value

Next step, we need to hash the spliced ​​string. In PHP, you can use the sha1() or md5() function to hash a string. The following code demonstrates how to hash passwords and salt values:

$hashed_password = sha1($salted_password);

In the above code, we use the sha1() function to hash $salted_password, and the generated hash value is $hashed_password .

Step 4: Save the salt and hash values ​​to the database

Now that we have successfully salted and hashed the password entered by the user, next we need to The salt and hash values ​​are saved to the database. When logging in, we need to compare the password entered by the user with the hash value in the database to determine whether the password is correct. The following code demonstrates how to save salt and hash values ​​to the database:

// 将盐值和哈希值保存到数据库
$sql = "INSERT INTO users (username, salt, hash) VALUES ('$username', '$salt', '$hashed_password')";

In the above code, we saved $username, $salt, and $hashed_password to the database.

Step 5: Check whether the password is correct

When logging in, we need to compare the password entered by the user with the hash value in the database to determine whether the password is correct. The following code demonstrates how to check whether the password is correct:

// 获取数据库中保存的盐值和哈希值
$sql = "SELECT salt, hash FROM users WHERE username = '$username'";
$result = mysqli_query($conn, $sql);
$row = mysqli_fetch_assoc($result);
$salt = $row['salt'];
$hashed_password = $row['hash'];

// 将用户输入的密码和盐值拼接起来，并进行哈希
$salted_password = $salt . $password;
$hashed_password_check = sha1($salted_password);

// 检查哈希值是否相等
if ($hashed_password_check === $hashed_password) {
    // 密码正确
} else {
    // 密码错误
}

In the above code, we first get the saved salt value and hash value from the database, and then hash the password and salt value entered by the user hope. Finally, we check if the hashes are equal, if so, the password is correct, otherwise the password is wrong.

Summary

In this article, we introduced the PHP salting method, which can be used to improve the security of passwords. By generating a random salt value and concatenating the salt value and the password for hashing, the difficulty of cracking the password can be greatly increased. In actual development, we can apply this method to the user registration and login process to protect the user's password.

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