PHP 隨機密碼產生器類別：支援大小寫、數字、特殊符號彈性配置

Password 類別完整代碼

<?php
/**
 * PHP 密碼產生器類別
 * Version 1.0.0
 */
class Password {
    protected $uppercase_chars = [];
    protected $lowercase_chars = [];
    protected $number_chars    = [];
    protected $special_chars   = [];
    protected $extra_chars     = [];
    protected $chars           = []; // 最終字元池
    
    public $length  = 12;
    public $uppercase = true;
    public $lowercase = true;
    public $number    = true;
    public $special   = false;
    public $extra     = false;

    public function __construct($length = 12) {
        $this->length = $length;
        $this->configure(true, true, true, false, false);
    }

    public function configure($uppercase = false, $lowercase = false, $number = false, $special = false, $extra = false) {
        $this->chars = [];
        
        $this->uppercase_chars = range('A', 'Z');
        $this->lowercase_chars = range('a', 'z');
        $this->number_chars    = array_merge(range(0,9), range(0,9)); // 數字權重加倍
        $this->special_chars   = array('!','@','#','$','%','^','&','*','(',')');
        $this->extra_chars     = array('[',']','{','}','-','_','+','=','<','>','?','/','`','~','|',',','.',';',':');
        
        if (($this->uppercase = $uppercase)) $this->chars = array_merge($this->chars, $this->uppercase_chars);
        if (($this->lowercase = $lowercase)) $this->chars = array_merge($this->chars, $this->lowercase_chars);
        if (($this->number    = $number))    $this->chars = array_merge($this->chars, $this->number_chars);
        if (($this->special   = $special))   $this->chars = array_merge($this->chars, $this->special_chars);
        if (($this->extra     = $extra))     $this->chars = array_merge($this->chars, $this->extra_chars);
        
        $this->chars = array_unique($this->chars);
    }

    public function generate() {
        if (empty($this->chars)) return false;
        
        $password = '';
        $maxIndex = count($this->chars) - 1;
        
        for ($i = 0; $i < $this->length; $i++) {
            $password .= $this->chars[$this->random(0, $maxIndex)];
        }
        return $password;
    }

    // 加密安全隨機數
    protected function random($min = 0, $max = 0) {
        // PHP 7+ 建議用 random_int()
        if (function_exists('random_int')) {
            return random_int($min, $max);
        }
        
        // 相容舊版本：使用 openssl_random_pseudo_bytes
        if (function_exists('openssl_random_pseudo_bytes')) {
            $bytes = openssl_random_pseudo_bytes(4);
            $val = unpack('L', $bytes)[1];
            return $min + ($max - $min + 1) * $val / 0x100000000;
        }
        
        // 最後回退：mt_rand（非加密安全）
        return mt_rand($min, $max);
    }
}

使用範例

<?php
require_once 'Password.php';

// 預設：12 碼，大小寫+數字
$gen = new Password();
echo $gen->generate() . "\n"; // 例：K7mP9qW2zR4x

// 自訂：16 碼，全字元集
$gen2 = new Password(16);
$gen2->configure(true, true, true, true, true);
echo $gen2->generate() . "\n"; // 例：pK9@mL2#zX5!qW8~

// 只產生數字 PIN
$pin = new Password(6);
$pin->configure(false, false, true, false, false);
echo $pin->generate() . "\n"; // 例：839201

安全性分析與改進

現代化重寫（PHP 7.1+）

<?php
class SecurePasswordGenerator {
    private $pools = [
        'upper' => 'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
        'lower' => 'abcdefghijklmnopqrstuvwxyz',
        'digit' => '0123456789',
        'special' => '!@#$%^&*()-_=+[]{}|;:,.<>?',
    ];
    
    public function generate(int $length = 16, array $enabled = ['upper','lower','digit','special']): string {
        $charset = '';
        foreach ($enabled as $pool) {
            if (isset($this->pools[$pool])) $charset .= $this->pools[$pool];
        }
        if (!$charset) throw new InvalidArgumentException('At least one pool required');
        
        $bytes = random_bytes($length);
        $password = '';
        for ($i = 0; $i < $length; $i++) {
            $password .= $charset[$bytes[$i] % strlen($charset)];
        }
        return $password;
    }
}

線上工具參考

• 高強度密碼生成：在線工具
• MD5/SHA1 雜湊：MD5 / SHA1