带你读懂区块链五大分类
区块链的定义很多人都讲过了，大部分人的拆解都是从内涵角度来论述的。从本质上来说，区块链就是一个采用分布式一致性算法的数据库。
为了更好的理解区块链，今天这篇，尝试从外延角度来跟大家聊聊现有区块链的分类。
一、按开放程度划分：公有链、联盟链、私有链
这个划分应该得到了大部分人的认同，就简单说说自己的理解：
1、公有链：人人可参与
典型案例：BTC、ETH
特征：系统最为开放，任何人都可以参与区块链数据的维护和读取，容易部署应用程序，完全去中心化不受任何机构控制。
如果拿现实来类比，公有区块链可能就像我们所处的大自然或者宇宙，人人都在其中，没有或者尚未发现任何主导的中心力量。
目前很多人在聊区块链的概念的时候，几米感觉其实聊的都是公有区块链的概念。比如有人理解为区块链是公共数据库，而很明显联盟链和私有链并不属于公共数据库。
2、联盟链：仅限联盟成员参与
典型案例：R3联盟、原本链
特征：系统半开放，需要注册许可才能访问的区块链。从使用对象来看，联盟链仅限于联盟成员参与，联盟规模可以大到国与国之间，也可以是不同的机构企业之间。
用现实来类比，联盟链就像各种商会联盟，只有组织内的成员才可以共享利益和资源，区块链技术的应用只是为了让联盟成员间彼此更加信任。
联盟链往往采取指定节点计算的方式，且记账节点数量相对较少。可能就因为这个原因，在一次线下活动时，有个朋友认为EOS本质上也是一条联盟链。这个说法很有意思，大家不妨探讨一下。
3、私有链：仅限个人或公司内部参与
典型案例：Multichain
特征：系统最为封闭，仅限于企业、国家机构或者单独个体内部使用，不完全能够解决信任问题，但是可以改善可审计性。
跟现实类比，私有链就像私人住宅一样，一般都是个人使用。擅闯民宅，是犯法的。侵入私有链，就像黑客入侵数据库一样。
不少人可能觉得私有链跟传统的分布式数据库没啥区别，技术上我不太确认，还需要更专业的人士一起交流探讨下。
以上内容部分参考一下，如果我说的还不够详细，那么可以看看这个图：
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