使用php生成RSA公钥私钥及进行加密/解密/签名/验证

<?php

/**
 * RSA算法类
 * 签名及密文编码：base64字符串/十六进制字符串/二进制字符串流
 * 填充方式: PKCS1Padding（加解密）/NOPadding（解密）
 *
 * Notice:Only accepts a single block. Block size is equal to the RSA key size!
 * 如密钥长度为1024 bit，则加密时数据需小于128字节，加上PKCS1Padding本身的11字节信息，所以明文需小于117字节
 */
class RSA
{
    private $pubKey = null;
    private $priKey = null;

    /**
     * 构造函数
     */
    public function __construct()
    {
        // 需要开启openssl扩展
        if (!extension_loaded("openssl")) {
            $this->_error("Please open the openssl extension first.");
        }
    }

    /**
     * 读取公钥和私钥
     * @param string $public_key_file 公钥文件（验签和加密时传入）
     * @param string $private_key_file 私钥文件（签名和解密时传入）
     */
    public function init($public_key_file = '', $private_key_file = '')
    {
        if ($public_key_file) {
            $this->_getPublicKey($public_key_file);
        }

        if ($private_key_file) {
            $this->_getPrivateKey($private_key_file);
        }
    }

    /**
     * 自定义错误处理
     */
    private function _error($msg)
    {
        die('RSA Error:' . $msg); //TODO
    }

    /**
     * 检测填充类型
     * 加密只支持PKCS1_PADDING
     * 解密支持PKCS1_PADDING和NO_PADDING
     *
     * @param int 填充模式
     * @param string 加密en/解密de
     * @return bool
     */
    private function _checkPadding($padding, $type)
    {
        if ($type == 'en') {
            switch ($padding) {
                case OPENSSL_PKCS1_PADDING:
                    $ret = true;
                    break;
                default:
                    $ret = false;
            }
        } else {
            switch ($padding) {
                case OPENSSL_PKCS1_PADDING:
                case OPENSSL_NO_PADDING:
                    $ret = true;
                    break;
                default:
                    $ret = false;
            }
        }
        return $ret;
    }

    private function _encode($data, $code)
    {
        switch (strtolower($code)) {
            case 'base64':
                $data = base64_encode('' . $data);
                break;
            case 'hex':
                $data = bin2hex($data);
                break;
            case 'bin':
            default:
        }
        return $data;
    }

    private function _decode($data, $code)
    {
        switch (strtolower($code)) {
            case 'base64':
                $data = base64_decode($data);
                break;
            case 'hex':
                $data = $this->_hex2bin($data);
                break;
            case 'bin':
            default:
        }
        return $data;
    }

    private function _getPublicKey($file)
    {
        $key_content = $this->_readFile($file);
        if ($key_content) {
            $this->pubKey = openssl_get_publickey($key_content);
        }
    }

    private function _getPrivateKey($file)
    {
        $key_content = $this->_readFile($file);
        if ($key_content) {
            $this->priKey = openssl_get_privatekey($key_content);
        }
    }

    private function _readFile($file)
    {
        $ret = false;
        if (!file_exists($file)) {
            $this->_error("The file {$file} is not exists");
        } else {
            $ret = file_get_contents($file);
        }
        return $ret;
    }

    private function _hex2bin($hex = false)
    {
        $ret = $hex !== false && preg_match('/^[0-9a-fA-F]+$/i', $hex) ? pack("H*", $hex) : false;
        return $ret;
    }

    /**
     * 生成Rsa公钥和私钥
     * @param int $private_key_bits 建议：[512, 1024, 2048, 4096]
     * @return array
     */
    public function generate(int $private_key_bits = 1024)
    {
        $rsa = [
            "private_key" => "",
            "public_key" => ""
        ];

        $config = [
            "digest_alg" => "sha512",
            "private_key_bits" => $private_key_bits, #此处必须为int类型
            "private_key_type" => OPENSSL_KEYTYPE_RSA,
        ];

        //创建公钥和私钥
        $res = openssl_pkey_new($config);

        //提取私钥
        openssl_pkey_export($res, $rsa['private_key']);

        //生成公钥
        $rsa['public_key'] = openssl_pkey_get_details($res)["key"];
        /*Array
        (
            [bits] => 512
            [key] =>
            [rsa] =>
            [type] => 0
        )*/
        return $rsa;
    }

    /**
     * 生成签名
     *
     * @param string 签名材料
     * @param string 签名编码（base64/hex/bin）
     * @return bool|string 签名值
     */
    public function sign($data, $code = 'base64')
    {
        $ret = false;
        if (openssl_sign($data, $ret, $this->priKey)) {
            $ret = $this->_encode($ret, $code);
        }
        return $ret;
    }

    /**
     * 验证签名
     *
     * @param string 签名材料
     * @param string 签名值
     * @param string 签名编码（base64/hex/bin）
     * @return bool
     */
    public function verify($data, $sign, $code = 'base64')
    {
        $ret = false;
        $sign = $this->_decode($sign, $code);
        if ($sign !== false) {
            switch (openssl_verify($data, $sign, $this->pubKey)) {
                case 1:
                    $ret = true;
                    break;
                case 0:
                case -1:
                default:
                    $ret = false;
            }
        }
        return $ret;
    }

    /**
     * 加密
     *
     * @param string 明文
     * @param string 密文编码（base64/hex/bin）
     * @param int 填充方式（貌似php有bug，所以目前仅支持OPENSSL_PKCS1_PADDING）
     * @return string 密文
     */
    public function encrypt($data, $code = 'base64', $padding = OPENSSL_PKCS1_PADDING)
    {
        $ret = false;
        if (!$this->_checkPadding($padding, 'en')) $this->_error('padding error');
        if (openssl_public_encrypt($data, $result, $this->pubKey, $padding)) {
            $ret = $this->_encode($result, $code);
        }
        return $ret;
    }

    /**
     * 解密
     *
     * @param string 密文
     * @param string 密文编码（base64/hex/bin）
     * @param int 填充方式（OPENSSL_PKCS1_PADDING / OPENSSL_NO_PADDING）
     * @param bool 是否翻转明文（When passing Microsoft CryptoAPI-generated RSA cyphertext, revert the bytes in the block）
     * @return string 明文
     */
    public function decrypt($data, $code = 'base64', $padding = OPENSSL_PKCS1_PADDING, $rev = false)
    {
        $ret = false;
        $data = $this->_decode($data, $code);
        if (!$this->_checkPadding($padding, 'de')) $this->_error('padding error');
        if ($data !== false) {
            if (openssl_private_decrypt($data, $result, $this->priKey, $padding)) {
                $ret = $rev ? rtrim(strrev($result), "\0") : '' . $result;
            }
        }
        return $ret;
    }
}

<?php

if (!class_exists("RSA")) {
    require_once "Rsa.class.php";
}

$private_key_file = __DIR__ . "/cert/private_key.pem";
$public_key_file = __DIR__ . "/cert/public_key.pem";

$rsa = new RSA();

// 没有就生成一对
if (!file_exists($private_key_file) || !file_exists($public_key_file)) {
    $key = $rsa->generate();

    file_put_contents($private_key_file, $key['private_key'], LOCK_EX);
    file_put_contents($public_key_file, $key['public_key'], LOCK_EX);
} else {
    $key = [
        "private_key" => file_get_contents($private_key_file),
        "public_key" => file_get_contents($public_key_file)
    ];
}

//显示数据
echo "private_key:\n" . $key['private_key'] . "\n\r";
echo "public_key:\n" . $key['public_key'] . "\n\r";

//要加密的数据
$data = "Web site:http://blog.kilvn.com";
echo '加密的数据：' . $data, "\n-------------------------------\n";

$rsa->init($public_key_file, $private_key_file);


//加密
$encrypt = $rsa->encrypt($data);
echo "公钥加密后的数据: " . $encrypt . "\n";

//解密
$decrypt = $rsa->decrypt($encrypt);
echo "私钥解密后的数据: " . $decrypt, "\n-------------------------------\n";

//签名
$sign = $rsa->sign($data);
echo "签名的数据: " . $sign . "\n";

//验证
$verify = $rsa->verify($data, $sign);
echo "验证的数据: " . $verify . "\n", "\n-------------------------------\n";