ALPN协议
协议介绍
ALPN (Application Layer Protocol Negotiation)应用层协议协商是TLS的扩展,允许在安全连接的基础上进行应用层协议的协商。ALPN支持任意应用层协议的协商,目前应用最多是HTTP2的协商。在2016年,ALPN已经完全替代NPN了。
ALPN allows the application layer to negotiate which protocol to use over the secure connection. Any protocol can be negotiated by ALPN within a TLS connection. The protocols that are most commonly negotiated are HTTP/2 (for browsers that support it) and, historically, SPDY. The ALPN implementation is therefore not HTTP/2 or SPDY specific in any way.
协商原理
在TLS的Say Hello阶段增加应用层协议的协商,如下图所示:
通过协商获取下一层协议,如下wireshark中显示
客户端的cient hello中:
服务端响应的Server hello中:
如果需要支持ALPN需要使用openssl1.0.2以上版本,
此协议扩展密钥计算不影响。
标签:TLS,协议,protocol,协商,ALPN,应用层 From: https://www.cnblogs.com/lizm166/p/16820594.html