-----BEGIN PUBLIC KEY-----
//64chars一行(多行)
-----END PUBLIC KEY-----
-----BEGIN RSA PRIVATE KEY-----
//64chars一行(多行)
-----END RSA PRIVATE KEY-----

/**
 * 将字符串格式公私钥格式化为pem格式公私钥
 * @param $secret_key
 * @param $type
 * @return string
 */
public static function format_secret_key($secret_key, $type){
  //64个英文字符后接换行符"\n",最后再接换行符"\n"
  $key = (wordwrap($secret_key, 64, "\n", true))."\n";
  //添加pem格式头和尾
  if ($type == 'pub') {
    $pem_key = "-----BEGIN PUBLIC KEY-----\n" . $key . "-----END PUBLIC KEY-----\n";
  }else if ($type == 'pri') {
    $pem_key = "-----BEGIN RSA PRIVATE KEY-----\n" . $key . "-----END RSA PRIVATE KEY-----\n";
  }else{
    echo('公私钥类型非法');
    exit();
  }
  return $pem_key;
}

/**
 * RSA加签
 * @param $paramStr
 * @param $priKey
 * @return string
 */
public static function sign($paramStr, $priKey){
  $sign = '';
  //将字符串格式公私钥转为pem格式公私钥
  $priKeyPem = SignUtil::format_secret_key($priKey, 'pri');
  //转换为openssl密钥，必须是没有经过pkcs8转换的私钥
  $res = openssl_get_privatekey($priKeyPem);
  //调用openssl内置签名方法，生成签名$sign
  openssl_sign($paramStr, $sign, $res);
  //释放资源
  openssl_free_key($res);
  //base64编码签名
  $signBase64 = base64_encode($sign);
  //url编码签名
  $sign = urlencode($signBase64);
  return $sign;
}

/**
 * RSA验签
 * @param $paramStr
 * @param $sign
 * @param $pubKey
 * @return bool
 */
public static function verify($paramStr, $sign, $pubKey) {
  //将字符串格式公私钥转为pem格式公私钥
  $pubKeyPem = SignUtil::format_secret_key($pubKey, 'pub');
  //转换为openssl密钥，必须是没有经过pkcs8转换的公钥
  $res = openssl_get_publickey($pubKeyPem);
  //url解码签名
  $signUrl = urldecode($sign);
  //base64解码签名
  $signBase64 = base64_decode($signUrl);
  //调用openssl内置方法验签，返回bool值
  $result = (bool)openssl_verify($paramStr, $signBase64, $res);
  //释放资源
  openssl_free_key($res);
  //返回资源是否成功
  return $result;
}