<?php

 　　/*

      * RSA2签名

      * @param array 请求的参数

      * @param string 私钥

      * return  string

      * time 2019-09-11

      * author chen

      * email 869476711@qq.com

      *

      * */

     protected function RSA2($data,$pikey){

         //将请求的参数进行排序

         ksort($data);//ksort()函数 根据参数的键进行升序排序

         reset($data);

         $signStr = '';

         foreach ($data as $key => $value) {

             if ($key == 'sign' || $value == '') continue;

             $signStr .= $key .'=' .$value .'&';

         }

         $signStr = substr($signStr, 0, -1);

         $res = "-----BEGIN RSA PRIVATE KEY-----\n" . wordwrap($pikey, 64, "\n", true) . "\n-----END RSA PRIVATE KEY-----";

         // 请注意密钥 是不是有带   -----BEGIN RSA PRIVATE KEY-----   -----END RSA PRIVATE KEY-----

         $piKey = openssl_pkey_get_private($res);

         if ($piKey) {

             $res = openssl_get_privatekey($res);

             openssl_sign($signStr, $sign, $res, 'SHA256');

             $sign = base64_encode($sign);

             openssl_free_key($piKey);

             return $sign;

         }

     }