Bai Shuo says blockchain
the traditional means of right protection are very limited. In history, there was a method of using postmark to protect right, that is, the author sent the manuscript in plicate, one to the publishing agency, and the other to himself. When there is a case of theft, take out the one in your hand as the evidence of the lawsuit, because the postmark is consistent in time and content
the characteristics of blockchain technology can effectively solve the problem of timely confirmation of rights. Distributed ledger is a kind of database shared, copied and synchronized among network members. Distributed ledger can realize synchronization, replication and sharing. Different from the centralized database, the centralized database is vulnerable to hacker attack or data loss. Once the centralized network is attacked, the loss will be immeasurable
distributed ledger is point-to-point, because many entities have the same set of independent and complete data copies, so the data stored in distributed ledger can effectively avoid the problem of data loss. For the registration and certification of right, the right data will not be easily tampered after being confirmed on the blockchain platform<
the Xueshuo innovation blockchain Technology Workstation of Lianqiao ecation online is the only approved "blockchain Technology Specialty" pilot workstation of "smart learning workshop 2020 Xueshuo innovation workstation" launched by the school planning, construction and development center of the Ministry of ecation of China. Based on providing diversified growth paths for students, the professional station promotes the reform of the training mode of the combination of professional degree research, proction, learning and research, and constructs the applied and compound talent training system.
As an emerging technology, blockchain has attracted more and more attention. It is a new application of traditional technology in the Internet era, including distributed data storage technology, consensus mechanism and cryptography. With the establishment of various blockchain research alliances, more and more funds and personnel support related research. Hash algorithm, zero knowledge proof, ring signature and other cryptographic algorithms used in blockchain:
hash algorithm
as the basic technology of blockchain, the essence of hash function is to map a set of data of any length (limited) to a set of defined length data stream. If this function satisfies the following conditions:
(1) the calculation of hash value for any group of data is very simple
(2) it is difficult to find two different data with the same hash value
hash functions satisfying the above two properties are also called encrypted hash functions. In case of no contradiction, hash functions usually refer to encrypted hash functions. For the hash function, finding such that is called a collision. The current popular hash functions are MD5, SHA1, Sha2, Sha3
bitcoin uses sha256, and most blockchain systems use sha256 algorithm. So here's sha256< Step 1: additional filling bits. The length of the message is congruent with that of 448 mod512 (length = 448 mod512). The number of bits to be filled ranges from 1 to 512. The highest bit of the filled bit string is 1, and the rest bits are 0
Step2: additional length value. The bit length of the initial message (before filling) represented by 64 bit is appended to the result of step 1 (the low byte takes precedence)
Step3: initialize cache. A 256 bit cache is used to store the intermediate and final results of the hash function
Step 4: process 512 bit (16 word) packet sequence. The algorithm uses six basic logic functions and consists of 64 steps of iterative operation. Each step takes the 256 bit cache value as the input, and then updates the cache content. Each step uses a 32-bit constant KT and a 32-bit wt. Where WT is the packet after the packet, t = 1,2,..., 16
step5: after all 512 bit packets are processed, the output of the last packet of sha256 algorithm is 256 bit packet< In 2001, Rivest, Shamir and TauMan proposed ring signature for the first time. It is a simplified group signature, only ring members have no manager, and it does not need the cooperation between ring members. In the ring signature scheme, the signer first selects a temporary signer set, which includes signers. Then the signer can generate the signature independently by using his private key and the public key of others in the signature set without the help of others. Members of the signer collection may not know that they are included in it
ring signature scheme consists of the following parts:
(1) key generation. A key pair (public key PKI, private key ski) is generated for each member of the ring
(2) signature. The signer uses his private key and the public keys of any n ring members (including himself) to generate the signature a for the message M
(3) signature verification. According to the ring signature and message M, the verifier verifies whether the signature is signed by the member in the ring. If it is valid, it will be received, otherwise it will be discarded
ring signature satisfies the following properties:
(1) unconditional anonymity: the attacker can not determine which member of the ring generated the signature, even if the private key of the ring member is obtained, the probability is not more than 1 / n
(2) Correctness: the signature must be verifiable by all others
(3) unforgeability: other members of the ring can't forge the real signer's signature, and even if an external attacker obtains a valid ring signature, he can't forge a signature for message M
(1) anonymity. The verifier can verify that the signature is signed by a member of the group, but can't know which member it is, so that the signer can be anonymous< (2) traceability. In group signature, the existence of group administrator ensures the traceability of signature. The group administrator can revoke the signature and expose the real signer. The ring signature itself cannot reveal the signer unless the signer wants to expose or add additional information to the signature. A verifiable ring signature scheme is proposed. In this scheme, the real signer wants the verifier to know his identity. At this time, the real signer can confirm his identity by disclosing his secret information< (3) management system. Group signature is managed by group administrator, ring signature does not need to be managed, signer can only select a set of possible signers, obtain its public key, and then publish the set, all members are equalthe Xueshuo innovation blockchain Technology Workstation of Lianqiao ecation online is the only approved "blockchain Technology Specialty" pilot workstation of "smart learning workshop 2020 Xueshuo innovation workstation" launched by the school planning, construction and development center of the Ministry of ecation of China. Based on providing diversified growth paths for students, the professional station promotes the reform of the training mode of the combination of professional degree research, proction, learning and research, and constructs the applied and compound talent training system< br />
through the blockchain, communication services can organize the operation of communication services without the mode of central enterprise. In the future, blockchain should have a real impact on real life, not just by concept and hype, but by real landing procts. What is really landing procts is procts that can meet the needs of users. If the existing centralized procts can well meet the needs of users, then the decentralized procts will not have enough substitution effect, and can not be truly implemented
the protocol layer of blockchain mainly includes four aspects: network programming, distributed algorithm, encrypted signature and data storage technology
the ability of network programming is the main factor for us to choose a programming language, because distributed algorithm is basically the implementation of business logic and can be achieved in any language. The encryption signature technology is directly and simply used, and the database technology is mainly used. Only the implementation of point-to-point network and concurrent processing is the difficulty of development. Therefore, for those languages with strong network programming ability and simple concurrency processing, people especially prefer them
users get the initial number of tokens for free. Some of its practical use scenarios:
1. Encrypted video chat: multinational users want to have video chat, only when both sides hold a certain number of SKM can they achieve encrypted video chat
2. Large capacity file encrypted transmission: the file transmitted by one user to another user exceeds the size limit, and the sender must hold a certain token to realize encrypted transmission
3. Conversation information saving: conversation records can be saved as long as both parties agree, and both parties need to hold a certain amount of tokens
4. Retransmission reminder: if a user sends a file to another user, but he doesn't want the other user to share it, the user can use a certain token to be notified when the file is retransmitted
5. Secret key unlock file: one user transfers the secret key file to another, and only the other party is allowed to view it. The sending user can use the token to let the other party receive the fragmented file. Only by getting the secret key from the sender can the file be unlocked<
the Xueshuo innovation blockchain Technology Workstation of Lianqiao ecation online is the only approved "blockchain Technology Specialty" pilot workstation of "smart learning workshop 2020 Xueshuo innovation workstation" launched by the school planning, construction and development center of the Ministry of ecation of China. Based on providing diversified growth paths for students, the professional station promotes the reform of the training mode of the combination of professional degree research, proction, learning and research, and constructs the applied and compound talent training system.
When it comes to blockchain, we often encounter the concept of "decentralization". So what is decentralization? Nakamoto has solved the difficult problem of "point-to-point e-cash" defined by himself. In this process, he "invented" the blockchain technology. Bitcoin system integrates technology and theory of cryptography, game theory and software engineering. Blockchain technology is an innovation formed by ingenious combination of existing technologies. Nakamoto didn't solve the problem of "peer-to-peer e-cash" out of thin air. He followed the footsteps of his predecessors, but he completed the last leap
"decentralization" is the competitive advantage of removing the centralized central node. It does not mean that there is no center, but the center node is a relatively neutral existence. These central nodes will not be mandatory. For a fully decentralized system, the connection between nodes is not completed by specific nodes, and all nodes can store and update data on the system, so as to achieve openness
decentralized blockchain is essentially a decentralized distributed ledger database. The simple understanding is that the data of blockchain is stored in many nodes of the network. The traditional way of data storage exists in one or several large nodes in the network. From this point of view, the so-called centralization and decentralization is the difference in the number of nodes storing data. Therefore, the decentralization of blockchain is relative. Data only exists on one node, which must be centralized. But if there are 100 nodes, they can be said to be decentralized relative to one node, but the degree of decentralization is not the same. At the same time, centralization and decentralization are not contradictory, and they are not completely opposite, because the word "de" in decentralization means the process of weakening and eliminating the center, rather than the concept that there is absolutely no center, which is completely opposite to non centralization
the Xueshuo innovation blockchain Technology Workstation of Lianqiao ecation online is the only approved "blockchain Technology Specialty" pilot workstation of "smart learning workshop 2020 Xueshuo innovation workstation" launched by the school planning, construction and development center of the Ministry of ecation of China. Based on providing diversified growth paths for students, the professional station promotes the reform of the training mode of the combination of professional degree research, proction, learning and research, and constructs the applied and compound talent training system
blockchain 1.0 era: digital currency rate of return is the king
blockchain 2.0 era: smart contract provides infrastructure support for upper application development
blockchain 3.0: the subversion of business lies in the transformation of proction relations
all obstacles to the development of human society, Fundamentally speaking, they are all caused by "mutual distrust", especially various economic and financial crises. If human beings can solve the problem of mutual trust, then human beings will complete a very big leap forward
the development of blockchain has graally laid the foundation for this direction. Human beings are entering the era of "smart contract", which is the process of upgrading human trust mechanism. Once the smart contract is reached, human society is facing a new big upgrade. As a value creator, the value created by each indivial can be accurately recorded and the corresponding return can be obtained, There will be less and less mutual interference, and people are really moving towards independence and equality. Human civilization has evolved from "identity society" to "contract society", and blockchain is expected to lead human beings to transition from "contract society" to "smart contract society"
although blockchain has gone out of the conceptual stage, the current situation of blockchain technology development is that the underlying technology is not mature enough and the application scenarios are relatively limited. On the one hand, consensus algorithm and other core technologies of blockchain still have room for optimization and improvement; On the other hand, the processing efficiency of blockchain is difficult to meet the requirements of some high-frequency application environments in reality. Moreover, the current mainstream blockchain technology platforms are originated from foreign countries. Domestic blockchain technology service providers should patiently start from the bottom development, achieve independent and controllable technology, and strive to lead the global blockchain technology development. It still needs a certain period of time. It can be said that the whole domestic trend is waiting for the emergence of a super level blockchain project
the Xueshuo innovation blockchain Technology Workstation of Lianqiao ecation online is the only approved "blockchain Technology Specialty" pilot workstation of "smart learning workshop 2020 Xueshuo innovation workstation" launched by the school planning, construction and development center of the Ministry of ecation of China. Based on providing diversified growth paths for students, the professional station promotes the reform of the training mode of the combination of professional degree research, proction, learning and research, and constructs the applied and compound talent training system.