<?php

/**
 * Ras非对称加解密算法
 * 功能：1、生成公钥和私钥
 *       2、公钥和私钥的加密和解密
 * eg:
 * $generatePriAndPub = RsaAlg::generatePriAndPub();
 * $rsaAlg = new RsaAlg($generatePriAndPub['pubKey'], $generatePriAndPub['privKey']);//传入秘钥
 * //$rsaAlg = new RsaAlg("E:/rsa/rsa_public_key.pem", "E:/rsa/rsa_private_key.pem",true);//传入秘钥文件
 * $str = json_encode(['id'=>1,'name'=>"zhuangshan"],true);
 * $keyCode = $rsaAlg->public_encrypt($str); //用公密钥加密
 * echo $keyCode, '</br>';
 * $str = $rsaAlg->private_decrypt($keyCode); //用私密钥解密
 * echo $str, '</br>';
 * //=============================================================
 * $keyCode = $rsaAlg->private_encrypt($str); //用私密钥加密
 * echo $keyCode, '</br>';
 * $str = $rsaAlg->public_decrypt($keyCode); //用公密钥解密
 * echo $str, '</br>';
 */
class RsaAlg
{
    private $public_key = ''; //公密钥，可以外部传入 也可以自己生成
    private $private_key = ''; //私密钥
    private $public_key_resource = ''; //公密钥资源
    private $private_key_resource = ''; //私密钥资源

    public static $config = array(
        "digest_alg" => "sha512",
        "private_key_bits" => 2048,           //字节数  512 1024 2048  4096 等
        "private_key_type" => OPENSSL_KEYTYPE_RSA,   //加密类型
    );

    /**
     * 该静态方法用于生成公钥和私钥
     *
     * 注意 1、window中注意生成非对称秘钥，需要在openssl 的Openssl default config路径中指定正确的默认openssl.cnf
     */
    public static function generatePriAndPub()
    {
        $res = openssl_pkey_new(self::$config);
        $privKey = "";
        //从得到的资源中获取私钥  并把私钥赋给$privKey
        openssl_pkey_export($res, $privKey);
        //从得到的资源中获取公钥  并把公钥赋给$pubKey
        $pubKey = openssl_pkey_get_details($res);
        $pubKey = $pubKey["key"];
        return array('privKey' => $privKey, 'pubKey' => $pubKey);
    }

    /**
     * 架构函数
     * @param [string] $public_key [公密钥]
     * @param [string] $private_key [私密钥]
     * @Param isFile true表示文件地址 false 表示内容
     */
    public function __construct($public_key, $private_key, $isFile = false)
    {
        if ($isFile) {
            $this->public_key = file_get_contents($public_key);
            $this->private_key = file_get_contents($private_key);
        } else {
            $this->public_key = $public_key;
            $this->private_key = $private_key;
        }
        if (false == ($this->public_key_resource = $this->is_bad_public_key($this->public_key)) || false == ($this->private_key_resource = $this->is_bad_private_key($this->private_key))) {
            throw new Exception('public key or private key no usable');
        }
    }

    private function is_bad_public_key($public_key)
    {
        return openssl_pkey_get_public($public_key);
    }

    private function is_bad_private_key($private_key)
    {
        return openssl_pkey_get_private($private_key);
    }

    /**
     * 生成一对公私密钥 成功返回 公私密钥数组 失败 返回 false
     */
    public function create_key()
    {
        $res = openssl_pkey_new();
        if ($res == false) return false;
        openssl_pkey_export($res, $private_key);
        $public_key = openssl_pkey_get_details($res);
        return array('public_key' => $public_key["key"], 'private_key' => $private_key);
    }

    /**
     * 用私密钥加密
     */
    public function private_encrypt($input)
    {
        openssl_private_encrypt($input, $output, $this->private_key_resource);
        return base64_encode($output);
    }

    /**
     * 解密 私密钥加密后的密文
     */
    public function public_decrypt($input)
    {
        openssl_public_decrypt(base64_decode($input), $output, $this->public_key_resource);
        return $output;
    }

    /**
     * 用公密钥加密
     */
    public function public_encrypt($input)
    {
        openssl_public_encrypt($input, $output, $this->public_key_resource);
        return base64_encode($output);
    }

    /**
     * 解密 公密钥加密后的密文
     */
    public function private_decrypt($input)
    {
        openssl_private_decrypt(base64_decode($input), $output, $this->private_key_resource);
        return $output;
    }
}

//$generatePriAndPub = RsaAlg::generatePriAndPub();
//$rsaAlg = new RsaAlg($generatePriAndPub['pubKey'], $generatePriAndPub['privKey']);//传入秘钥
//$rsaAlg = new RsaAlg("E:/rsa/rsa_public_key.pem", "E:/rsa/rsa_private_key.pem",true);
//$str = json_encode(['id' => 1, 'name' => "zhuangshan"], true);
//$keyCode = $rsaAlg->public_encrypt($str); //用公密钥加密
//echo $keyCode, '</br>';
//$str = $rsaAlg->private_decrypt($keyCode); //用私密钥解密
//echo $str, '</br>';
////=============================================================
//$keyCode = $rsaAlg->private_encrypt($str); //用私密钥加密
//echo $keyCode, '</br>';
//$str = $rsaAlg->public_decrypt($keyCode); //用公密钥解密
//echo $str, '</br>';