什么是区块链

什么是区块链？区块链技术可以用来解决什么问题？

现有的商业网络通常都是低效的，这是因为这个网络中的每一个参与者都会保留一份该网络参与的所有交易的记录，或者说底账（ledger）。这一过程是昂贵的，因为其中存在冗余的劳动，并且中间商会为他们提供的服务收费。
这个问题的解决方案就是区块链。区块链技术提供了一个共享的账簿，使得该网络中的每一个参与者都可以看见同一个系统的总记录，或底账。通过适用区块链技术，企业可以从一个更有效的产品或服务交易体系中获利。

一个区块链网络主要有以下特点：

Consensus: 为了使一次交易有效，所有参与者必须认同它的有效性。
Provenance: 参与者知道这笔资产的来源以及它的所有权如何随时间改变。
Immutability: 一笔交易被记录到账本后，任何参与者都不能篡改交易记录。如果一笔交易发生错误，必须使用一个新的交易纠正这个错误，并且这两笔交易都是可见的。
Finality: 一个唯一的、共享的账本用来确定一笔资产的所有权或者一笔交易。

Key Business Benifits

Time savings
Cost savings
Tighter security

并不是所有的区块链都是为商业而构建的。有些是被许可的，而有些不是。被许可的区块链网络对于一个为商业服务的区块链是至关重要的，尤其对于受监管的行业来说 ，它提供了：

Enhanced privacy
Improved auditability
Increased operational efficiency

区块链通过以下5个属性建立信任

Distributed and sustainable: The ledger is shared, updated with every transaction, and selectively replicated among participants in near real time.
Secure, private, and indelible:
Transparent and auditable:
Consensus-based and transactional:
Orchestrated and flexible:

区块链的构建

The key concepts of blockchain for business

Shared ledger

Records all transactions across the business network; the shared ledger is the system of record, the single source of truth.
Is shared among all participants in the network; through replication, each participant has a duplicate copy of the ledger.
Is permissioned, so participants see only those transactions they’re authorized to view. Participants have identities that link them to transactions, but they can choose the transaction information that other participants are authorized to view.

Participants and Their Roles

• Blockchain user
• Regulator
• Blockchain developer
• Blockchain network operator：Individuals who have special permissions and authority to define, create, manage, and monitor the blockchain network. Each business on a blockchain network has a blockchain network operator.
• Traditional processing platforms
• Traditional data sources
• Certificate authority