[Summer 2021] Enhance application protection capability of Seata-Server

# Background

Generally speaking, the use of Seata-Server on a small scale in the Intranet will not expose security problems. However, as the scale of the business expands, it may be challenged by improper use and illegal access, triggering such problems as traffic overload, malicious access, packet leakage and so on.

The Seata community wants to open the task of improving the protection of Seata-Server applications to `Summer 2021`.

# Target

The goal of this issue is to improve the application protection capability of Seata-Server.

# Difficulty
Medium

# Mentor
@slievrly
[jimin.jm@alibaba-inc.com](mailto:jimin.jm@alibaba-inc.com)

# Output Requirements
* Support TLS transmission encryption.
* Support Server authentication blacklist configuration.
* Support flow limiting control for a single Server. Full limited flow control is optional.

# Technical Requirements
* Familiar with Java programming language.
* Understand common design patterns
* Ability to read source code

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# 背景

一般来说在内网小规模使用Seata-Server并不会暴露安全性问题，但是随着业务的规模的扩大，可能受到不当使用，非法访问等问题挑战，触发例如流量过载，恶意访问，数据包泄露等问题。

Seata 社区想将这个提升Seata-Server应用防护的任务开放给 `Summer 2021`。

# 目标

提升 Seata-Server 的应用防护能力。

# 难度
中等

# 导师
@slievrly
[jimin.jm@alibaba-inc.com](mailto:jimin.jm@alibaba-inc.com)

# 产出要求
* 支持TLS加密传输。
* 支持Seata-Server 访问黑名单控制。
* 支持单个Server的流量控制。全局限流是可选项。

# 能力要求
* 熟悉Java开发语言。
* 理解常见设计模式。
* 具备一定的源码阅读能力

Start by reading the Seata-Server source and clarifying the design with the listed mentor, since no files or tests are identified. The work is complete when Seata-Server supports TLS transmission encryption, configurable server authentication blacklists, and per-server flow limiting; global limiting is optional.

Written by the indexing model from the issue text.