php - 散列/加盐时密码不匹配

Question

好的，所以下面的所有代码都不是我自己的。我一直在关注 Internet 上的教程，但是当我尝试运行它时，似乎没有匹配的密码。我认为加盐密码可能存在错误，因为数据库中的内容与 login.php 脚本中描述的 64 个字符相去甚远。我不知道。代码如下:

register.php

// Create a 256 bit (64 characters) long random salt
// Let's add 'something random' and the username
// to the salt as well for added security
$salt = hash('sha256', uniqid(mt_rand(), true) . 'something random' . strtolower($username));

// Prefix the password with the salt
$hash = $salt . $password;

// Hash the salted password a bunch of times
for ( $i = 0; $i < 100000; $i ++ )
{
    $hash = hash('sha256', $hash);
}

// Prefix the hash with the salt so we can find it back later
$hash = $salt . $hash;

// carry on with registration code...

登录.php

$email = $_POST['email'];
$password = $_POST['password'];

$con = mysql_connect("localhost", "redacted", "redacted", "redacted");

$sql = '
    SELECT
        `password`
    FROM `users`
        WHERE `email` = "' . mysql_real_escape_string($email) . '"
    LIMIT 1
    ;';

$r = mysql_fetch_assoc(mysql_query($sql));

// The first 64 characters of the hash is the salt
$salt = substr($r['password'], 0, 64);

$hash = $salt . $password;

// Hash the password as we did before
for ( $i = 0; $i < 100000; $i ++ )
{
    $hash = hash('sha256', $hash);
}

$hash = $salt . $hash;

if ( $hash == $r['password'] )
{
    session_start();
    header('Location: /quiz/index.php');
}

if( $hash != $r['password'] ){
    session_start();
    header('Location: /?error=4');
}

// end login script

Answer 1

一个常见的错误是数据库字段的长度不足以存储所有字符。密码将永远不会等于用户输入的密码。

对于这种功能，始终编写单元测试来检查功能是否(仍然)按预期工作。有一天有人修改数据库，改hash算法，修改salt……就没人能登录了。