Blockchain 2.0-Starting from Bitcoin Diving
Bitcoin is diving again
前情提要：近期虚拟币市场可谓风波不断，就在此文书写的当天，部分比特币交易平台出现了从上次跳水后价格继续下跌10%以上的窘境
Recent Policy Review
- 8.30-9.3 Three major trading platforms suspend ICO trading business
- 9.4 The central bank and other seven ministries and commissions urgently suspend ICO transactions
- 9.8 The regulatory authorities force the shutdown of China and bid farewell to Bitcoin exchanges
- 9.2-12 Several Bitcoin trading platforms increase handling fees
- 9.14 16:00-18:00 News that the Bitcoin trading platform will be closed in Shanghai has been notified
- 9.14 At 19:00, the news of Bitcoin China’s suspension of all transactions at the end of September is basically true
under severe circumstances
It can be seen from the recent policies that the state is starting to control a series of relatively special gray industries such as bitcoin transactions. When it comes to Bitcoin, there is often "blockchain technology" on the lips, and some descriptions refer to "blockchain-based Bitcoin", then when the big policy is waiting to see virtual currency, the blockchain What is the impact of technology? Find out exactly how Bitcoin is related to the blockchain.
Birth of Bitcoin
In September 2008, starting with the collapse of Lehman Brothers, the financial crisis broke out in the United States and spread to the world. In response to the crisis, governments around the world have taken measures such as quantitative easing to rescue large financial institutions that have fallen into crisis due to their own faults. These measures raised widespread doubts and, at one point, sparked the "Occupy Wall Street" movement.
On the basis of previous work, in 2008, the little-known "Satoshi Nakamoto" published "Bitcoin: A Peer-to-Peer Cash Payment System" on the cryptography mailing list of metzdowd.com.
On January 3, 2009, Satoshi Nakamoto dug out the first block of Bitcoin, the Genesis Block, on a small server in Helsinki, Finland, and received the "first mine" reward- 50 bitcoins. In the genesis block, Satoshi Nakamoto wrote this sentence:
“The Times 03/Jan/2009 Chancellor on brink of second bailout for banks"
“财政大臣站在第二次救助银行的边缘”
what is blockchain
The data sharing of blockchain technology is a distributed ledger, which can be understood as a giant distributed decentralized database. The basic unit of blockchain storage is the block, and the block adopts a chain structure, that is, the newly added block (similar to a row of database records) knows what the previous block (the previous row of records) is, which can be traced back to the root. , the identifier of the block is the hash value of the block, and the chain structure retains the track generated by the business, which can be verified according to the previous record when adding a transaction, ensuring that the content of the block is not easily tampered with. Since it is a distributed and multi-center storage method, it is necessary to solve the problem of distributed consistency during storage. In the application of Bitcoin, the predecessor of the blockchain, the way to solve this problem is the proof-of-work (POW Proof-Of-Work) method, that is, to obtain specified results through work, and use the results to prove the efforts that have been made. PBFT Practical Byzantine Fault Tolerance is a mechanism for reaching consensus through technical rules.
Blockchain technology is a combination of technologies. Since it is a distributed ledger, it is necessary to solve the problem of reliable data transmission. It includes data transmission between accounting nodes (trusted nodes), non-accounting nodes (untrusted nodes), and between clients and accounting nodes (trusted nodes). In our previous solutions, the problem of data transmission was often solved by means of reliable messages or P2P, and these technologies were also used in blockchain technology.
The relationship between blockchain and bitcoin
Bitcoin and blockchain are two concepts, mentioning one of them will bring to mind the other. In the Bitcoin system, the most important thing is not the concept of "coin", but the concept of the database of the distributed decentralized storage organization mentioned above. Blockchain technology is the underlying technology of Bitcoin. Bitcoin has been running stably without any centralized organization's operation and management. Later, Bitcoin technology was abstracted out and called blockchain technology, or distributed ledger technology. Therefore, it can be said that Bitcoin is the first application of the blockchain, and the blockchain is a lower-level technology that will expand to more and more industries in the future.
Blockchain 2.0: Smart Contracts
The application of blockchain 1.0 is represented by bitcoin, in order to solve the decentralization of currency and payment methods; and blockchain 2.0 "smart contract" is a more macro-level decentralization of the entire market, using blockchain technology to convert Many different assets, not just Bitcoin, are transferred to create value for different units of assets.
Smart contracts can automatically execute digital contracts when certain conditions are met. To achieve this feature, in the database is completed by triggers and stored procedures. A smart contract in blockchain technology is a trigger and a stored procedure. It is a script that runs in a sandbox and is used to execute business logic in blockchain business and can also be used for various checks.
“智能合约是密码学世界真正的杀手级应用”，在世界加密网络上发布密码学货币节目的主持人Chris Ellis如此说。
Constraints of the Bitcoin System Blockchain
The idea of applying the idea of blockchain to other fields has long appeared, and since the successful development of the decentralized consensus of the Bitcoin system in 2009, many other applications of blockchain have begun to appear rapidly. Even without extending the Bitcoin protocol, it enables "smart contracts" to a certain extent. Bitcoin's UTXO can be owned not only by a public key, but also by more complex scripts written in stack-based programming languages. In this mode, to spend such a UTXO, data must be provided to satisfy the script. In fact, the basic public key ownership mechanism is also implemented through a script: the script takes the elliptic curve signature as input, verifies the transaction and the address that owns this UTXO, and returns 1 if the verification is successful, and 0 otherwise.
However, the scripting language of the Bitcoin system has some serious limitations:
- Lack of Turing completeness
- Value-blindness
- missing state
- Blockchain-blindness
Fabric
The Linux Foundation founded Hyperledger in 2015 to advance cross-industry blockchain technology. It encourages a collaborative approach to developing blockchain technology through a community process, encouraging open development and the adoption of intellectual property over key standards over time. Hyperledger Fabric is a blockchain project within Hyperledger, like other blockchain technologies, it has a ledger, using smart contracts, a system for participants to manage their transactions.
What differentiates Hyperledger Fabric from some other blockchain systems is that it is privately authenticated. By registering with a membership service provider, members of the Hyperblocker Fabric network do not use "proof of work" to verify identity (anyone who meets these criteria is allowed to join the network).
6 advantages of Fabric
- Permissioned member Hyperledger Fabric is known for being the platform for a permissioned network where all participants have known identities. When considering permissioned networks, you should consider whether your own blockchain use case is subject to data protection regulations. Many use cases—specifically, in the financial sector and the healthcare industry—need to comply with data protection laws that require knowing the identities of network members and those accessing specific data. For example, suppose there is a private equity firm. By definition, private equity is not publicly traded on stock exchanges, and its investors are usually venture capital firms, private equity firms, or angel investors. Participants in this network need to be known and have credibility in terms of capital investment before they can participate in the blockchain.
- Performance, Scalability, and Trust Levels Hyperledger Fabric is built on a modular architecture that divides transaction processing into 3 phases: distributed logic processing and negotiation ("chaincode"), transaction ordering, and transaction validation and submit. This separation provides several advantages: a lower level of trust and verification is required between different node types, and network scalability and performance are optimized.
- Expose data on a "need to know" basis. Due to the competitive landscape, protection laws and regulations regarding the confidentiality of personal data, businesses dictate the need to ensure the privacy of certain data elements, which can be achieved through data partitioning on the blockchain. Channels supported in Hyperledger Fabric allow data to be passed only to interested parties who need to know. For example, many financial entities have expressed concern that competitors see the volume of transactions processed. Some financial institutions do not consider "sufficient" encryption to protect their data. Given this situation, it may take 10 years or more for some financial instruments to become valuable, and over time the risk of password cracking could make private information public. Channels help to provide data partitioning capabilities, and only interested parties who need to know the data can see the number of transactions and the data itself.
- A rich query ledger on an immutable distributed ledger is an ordered record of the state transitions of a blockchain application. Each transaction produces a set of asset key-value pairs that are committed to the ledger in the form of create, update or delete data. v1.0's immutable source of truth is attached to the filesystem of the LevelDB-embedded peer. By default, LevelDB has a key-value database that supports key queries, composite key queries, and key range queries. If complex rich-format queries are also required, CouchDB supports the basic functionality of LevelDB and adds comprehensive rich-data queries. Optionally support document databases such as CouchDB, the content needs to be in JSON format, fully queryable, and its data model should be compatible with existing key/value programming models. Therefore, when leveraging CouchDB, no application changes are required if the chaincode data is modeled as JSON. This JSON format helps minimize the effort required to generate simple reports and perform audit functions. For example, in a supply chain scenario, JSON document styles can be used to help list specific data for commodities and shipping entities. Asset reports can be easily generated for the locations and shipping entities involved in the journey to the asset's final destination.
- Modular Architecture Supporting Plug-In Components The modularity of Hyperledger Fabric's architecture enables network designers to plug in components of their preferred implementation, which is an advantage. One of the most requested areas of modularity is "bring your own identity". Some multi-company networks already have identity management functionality and want to reuse that functionality rather than rebuild it. Other components that can be easily plugged into the architecture include conformance or encryption components, where some countries have their own encryption standards.
- Protecting Digital Keys and Sensitive Data HSM (Hardware Security Module) support is critical to protecting and managing digital keys for strong authentication. Hyperledger Fabric provides both modified and unmodified PKCS11 to generate keys, which supports handling various situations such as identity management that require more protection. For scenarios dealing with identity management, HSM adds protection for keys and sensitive data.
[Cloud Framework] Blockchain-based smart contracts, taking charity fundraising as an example, provides the best practices for implementing blockchain-based smart contract systems through Fabric.