ChainConfig.cbSize = sizeof(CERT_CHAIN_ENGINE_CONFIG);
    ChainConfig.hRestrictedRoot= NULL ;
    ChainConfig.hRestrictedTrust= NULL ;
    ChainConfig.hRestrictedOther= NULL ;
    ChainConfig.cAdditionalStore=0 ;
    ChainConfig.rghAdditionalStore = NULL ;
    ChainConfig.dwFlags = CERT_CHAIN_CACHE_END_CERT;
    ChainConfig.dwUrlRetrievalTimeout= 10000 ;
    ChainConfig.MaximumCachedCertificates=0 ;
    ChainConfig.CycleDetectionModulus = 0;

   CertCreateCertificateChainEngine(&ChainConfig,&hChainEngine;

    EnhkeyUsage.cUsageIdentifier = 0;
    EnhkeyUsage.rgpszUsageIdentifier=NULL;
    CertUsage.dwType = USAGE_MATCH_TYPE_AND;
    CertUsage.Usage  = EnhkeyUsage;
    ChainPara.cbSize = sizeof(CERT_CHAIN_PARA);
    ChainPara.RequestedUsage=CertUsage;
    CertGetCertificateChain(NULL,pCertContext, NULL,NULL, &ChainPara,  CERT_CHAIN_REVOCATION_CHECK_CHAIN,
	    NULL, &pChainContext));