diff --git a/alipay/utils/common.go b/alipay/utils/common.go
index 812b2b9..4083a88 100644
--- a/alipay/utils/common.go
+++ b/alipay/utils/common.go
@@ -23,6 +23,7 @@ func hex2dec(hex string) string {
 	return fmt.Sprintf("%d", dec)
 }
 
+// getCert 从证书数据中提取证书
 func getCert(certData []byte) (*x509.Certificate, error) {
 	block, _ := pem.Decode(certData)
 	if block == nil {