如何比较输入登录字段中输入的密码与数据库中存储的md5密码 - How to compare entered password in input login field with the md5 password stored in database?

UPDATE(solved):之前我将密码长度设置为15个字符，因为密码被加密为md5，所以应该是32个字符。现在它运行良好。谢谢你的回答和建议。

下面是注册php代码。代码工作良好，能够在数据库中存储md5密码。

  <html>
<?php
error_reporting(0);
if($_POST['submit'])
{
    $name = mysql_real_escape_string($_POST['name']);
    $username = mysql_real_escape_string($_POST['username']);
    $password = mysql_real_escape_string($_POST['password']);
    $password1 = mysql_real_escape_string($_POST['password1']);
    $enc_password = md5($password);
    if($name && $username && $password && $password1)
    {
        if(strlen($name)<30)
        {
            if(strlen($username)<10)
            {
                if(strlen($password)<15 || strlen($password)>6)
                {
                    if($password == $password1)
                    {
                        require "dbc.php";
                        $query = mysql_query("INSERT INTO users VALUES ('$name','$username','$enc_password')");     
                        echo "Registration Complete! <a href='index.php'>Click here to login</a>";
                    }
                    else
                    {
                        echo "Passwords must match";
                    }
                }
                else
                {
                    echo "Your password must be between 6 and 15 characters";   
                }
            }
            else
            {
                echo "Your username is too long";   
            }
        }
        else
        {
            echo "Your name is too long";
        }
    }
    else
    { 
        echo "All fields are required"; 
    }
}
?>
    <form action="register.php" method="POST">
        Name: <input type="text" name="name" value="<?php echo "$name"; ?>"> Max Length:30<p>
        Username: <input type="text" name="username" value="<?php echo "$username"; ?>"> Max Length:10<p>
        Password: <input type="password" name="password"> Max length:15<p>
        Re-Enter Password: <input type="password" name="password1"><p>
        <input type="submit" name="submit" value="Register">
    </form>
    <input type="button" value="<< Back to Login Area" onclick="window.location='../login%20and%20registration/members.php'">
</html>

下面是登录php代码。

    <?php
session_start();
require "dbc.php";
$username = mysql_real_escape_string($_POST['username']);
$password = mysql_real_escape_string($_POST['password']);
$enc_password = md5($password);
if($username&&$password)
{
    $query = mysql_query("SELECT * FROM users WHERE username='$username'");
    $numrow = mysql_num_rows($query);
if($numrow!=0)
{
    while($row = mysql_fetch_assoc($query))
    {
        $db_username = $row['username'];
        $db_password = $row['password'];
    }
    if($username==$db_username&&$password==$db_password)
    {
        //echo "Logged in <a href='members.php'>Click here to enter the members area</a>";
        $_SESSION['username']=$db_username;
        header("location: members.php");
    }
    else 
    {
        header("location: index.php?error=Incorrect Password");
    }
}
else 
{
    header("location: index.php?error=That user doesn't exist");
}
}
else 
{
    header("location: index.php?error=All fields are required");
}
?>

问题是当我尝试登录时，我一直得到"不正确的密码"。我想从数据库中找回密码有点问题。有人能帮忙吗?

您需要使用$enc_password代替$password:

if($username==$db_username&&$password==$db_password)

注:此外，如果你使用md5，那么不要做mysql_real_escape_string(), md5将改变你的字符串，所有的注入将被删除。

P.P.S.使用PDO代替mysql_*

用户名必须是不区分大小写所以最好这样做:

if(strcasecmp($username, $db_username)===0 && $password==$db_password)

strcasecmp

change

if($username==$db_username&&$password==$db_password)

if($username == $db_username && $enc_password == $db_password)

您使用的是$password，但它应该是$enc_password

你正在比较$password和$db_password，而你应该比较$enc_password和$db_password。

if($username==$db_username&&$enc_password==$db_password)

在你的情况下，你应该这样比较

 $password = md5($password);//change value entered of password to md5
 if($username==$db_username&&$password==$db_password)