如何使用盐与md5技术

Question

I have coded md5 technique to store the password in hash but I want to implement it with salt.

here is my register form php with md5 function which is working perfectly.

<?php
require("common.php");
if (! empty ( $_POST )) {
    if (empty ( $_POST ['username'] )) {
        die ( "Please enter a username." );
    }
    if (empty ( $_POST ['password'] )) {
        die ( "Please enter a password." );
    }
    $query = "SELECT 1 FROM User WHERE username = :username";
    $query_params = array (
            ':username' => $_POST ['username'] 
    );
    try {
        $stmt = $db->prepare ( $query );
        $result = $stmt->execute ( $query_params );
    } catch ( PDOException $ex ) {
        die ( "Failed to run query: " . $ex->getMessage () );
    }
    $row = $stmt->fetch ();
    if ($row) {
        die ( "This user name is already registered" );
    }
    $password = md5($_POST['password']);
    $query = "INSERT INTO User (username, password) VALUES (:username, :password)";
    $query_params = array (
            ':username' => $_POST ['username'],
            ':password' => $password 
    );
    try {
        $stmt = $db->prepare ( $query );
        $result = $stmt->execute ( $query_params );
    } catch ( PDOException $ex ) {
        die ( "Failed to run query: " . $ex->getMessage () );
    }
    header ( "Location: login.php" );
    die ( "Redirecting to login.php" );
}
?>

Answer 1

You should not use MD5 or SHA1 for hashing (even with a salt) as they are proven to be insecure.

Using salted md5 for passwords is a bad idea. Not because of MD5's cryptographic weaknesses, but because it's fast. This means that an attacker can try billions of candidate passwords per second on a single GPU.

PHP now provides a simple way to use the far more secure bcrypt hash through the password_hash function, which not only generates a strong hash, but generates a random salt as well

$password = password_hash($_POST['password'], PASSWORD_DEFAULT);