update readme for security

@@ -468,6 +468,10 @@ Supported operating systems and hardware:
 [EN](https://github.com/winlinvip/simple-rtmp-server/wiki/v2_EN_SrsLibrtmp#publish-audio-raw-stream)
 ) by srs-librtmp.
 1. Support 0.1s+ latency, read [#257](https://github.com/winlinvip/simple-rtmp-server/issues/257).
+1. Support allow/deny publish/play for all or specified ip(
+[CN](https://github.com/winlinvip/simple-rtmp-server/wiki/v2_CN_Security),
+[EN](https://github.com/winlinvip/simple-rtmp-server/wiki/v2_EN_Security)
+).
 1. [no-plan] Support <500ms latency, FRSC(Fast RTMP-compatible Stream Channel tech).
 1. [no-plan] Support RTMP 302 redirect [#92](https://github.com/winlinvip/simple-rtmp-server/issues/92).
 1. [no-plan] Support multiple processes, for both origin and edge