<?php
/**
 * API入参静态检查类
 * 可以对API的参数类型、长度、最大值等进行校验
 *
 **/
class NuomiRsaSign
{

    /**
     * @desc 私钥生成签名字符串
     * @param array $assocArr
     * @param $rsaPriKeyStr
     * @return bool|string
     * @throws Exception
     */
    public static function genSignWithRsa(array $assocArr, $rsaPriKeyStr)
    {
        $sign = '';
        if (empty($rsaPriKeyStr) || empty($assocArr)) {
            return $sign;
        }

        if (!function_exists('openssl_pkey_get_private') || !function_exists('openssl_sign')) {
            throw new Exception("openssl扩展不存在");
        }

        $priKey = openssl_pkey_get_private($rsaPriKeyStr);

        if (isset($assocArr['sign'])) {
            unset($assocArr['sign']);
        }

        ksort($assocArr); //按字母升序排序

        $parts = array();
        foreach ($assocArr as $k => $v) {
            $parts[] = $k . '=' . $v;
        }
        $str = implode('&', $parts);
        openssl_sign($str, $sign, $priKey);
        openssl_free_key($priKey);

        return base64_encode($sign);
    }

    /**
     * @desc 公钥校验签名
     * @param array $assocArr
     * @param $rsaPubKeyStr
     * @return bool
     * @throws Exception
     */
    public static function checkSignWithRsa(array $assocArr, $rsaPubKeyStr)
    {
        if (!isset($assocArr['sign']) || empty($assocArr) || empty($rsaPubKeyStr)) {
            return false;
        }

        if (!function_exists('openssl_pkey_get_public') || !function_exists('openssl_verify')) {
            throw new Exception("openssl扩展不存在");
        }

        $sign = $assocArr['sign'];
        unset($assocArr['sign']);

        if (empty($assocArr)) {
            return false;
        }
        ksort($assocArr); //按字母升序排序
        $parts = array();
        foreach ($assocArr as $k => $v) {
            $parts[] = $k . '=' . $v;
        }
        $str = implode('&', $parts);

        $sign = base64_decode($sign);
        $pubKey = openssl_pkey_get_public($rsaPubKeyStr);
        $result = (bool)openssl_verify($str, $sign, $pubKey);
        openssl_free_key($pubKey);

        return $result;
    }

}