The TLS protocol addresses network security problems such as tampering and eavesdropping between a client and a server. When a client establishes a TLS handshake to your API through your custom domain, your security policy will enforce your chosen TLS version and cipher suite options available to the client. A security policy is a predefined combination of a minimum TLS version and cipher suites offered by API Gateway. You can configure TLS versions and cipher suites for all existing and new API Gateway custom domains by selecting the TLS v1.2 or TLS v1.0 security policy. For more information please see our documentation.