PHP 中的密码安全性Password Hashing

如果你还在用md5加密，建议看看下方密码加密和验证方式。

先看一个简单的Password Hashing例子：

<?php

//require 'password.php';
/**
 * 正确的密码是secret-password
 * $passwordHash 是hash 后存储的密码
 * password_verify()用于将用户输入的密码和数据库存储的密码比对。成功返回true，否则false
 */
$passwordHash = password_hash('secret-password', PASSWORD_DEFAULT);
echo $passwordHash;
if (password_verify('bad-password', $passwordHash)) {
// Correct Password
    echo 'Correct Password';
} else {
    echo 'Wrong password';
// Wrong password
}

下方代码提供了一个完整的模拟的 User 类，在这个类中，通过使用Password Hashing，既能安全地处理用户的密码，又能支持未来不断变化的安全需求。

<?php
class User
{
// Store password options so that rehash & hash can share them:
const HASH = PASSWORD_DEFAULT;
const COST = 14;//可以确定该算法应多复杂，进而确定生成哈希值将花费多长时间。（将此值视为更改算法本身重新运行的次数，以减缓计算。）

// Internal data storage about the user:
public $data;

// Mock constructor:
public function __construct() {
// Read data from the database, storing it into $data such as:
// $data->passwordHash and $data->username
$this->data = new stdClass();
$this->data->passwordHash = 'dbd014125a4bad51db85f27279f1040a';
 }

// Mock save functionality
public function save() {
// Store the data from $data back into the database
 }

// Allow for changing a new password:
public function setPassword($password) {
$this->data->passwordHash = password_hash($password, self::HASH, ['cost' => self::COST]);
 }

// Logic for logging a user in:
public function login($password) {
// First see if they gave the right password:
echo "Login: ", $this->data->passwordHash, "\n";
if (password_verify($password, $this->data->passwordHash)) {
// Success - Now see if their password needs rehashed
if (password_needs_rehash($this->data->passwordHash, self::HASH, ['cost' => self::COST])) {
// We need to rehash the password, and save it. Just call setPassword
$this->setPassword($password);
$this->save();
 }
return true; // Or do what you need to mark the user as logged in.
 }
return false;
 }
}

原文链接：更新后的 PHP: 现代 PHP 中的密码安全性

参考链接：http://wulijun.github.io/php-the-right-way/#data_filtering