Blockchain independent code
a brief history of etheric Classics (etc)
etheric classics began with an unfortunate event
in May 2016, the decentralized autonomous organization (DAO) held a token sale with the goal of establishing a blockchain based venture capital to fund future decentralized applications (dapps) in the Ethereum ecosystem
basically, Dao is a complex smart contract that operates in a decentralized way - computer code that automatically performs tasks between multiple parties when conditions are met
despite its ambitious goals and successful token sales, Dao's code has a major vulnerability that allows attackers to steal eth from decentralized organizations
the attacker took advantage of this vulnerability in June 2016, triggering the infamous Dao hacking event, and maliciously stole eth worth about US $50 million
there is no doubt that Dao hacking has shocked Ethereum community and made eth price drop from $20 to $13
after the Dao hacking, the Ethereum community has to choose from three options
< UL >do nothing and try to bear the consequences of the attack
start soft bifurcation to recover funds
deploy a hard fork to recover the lost eth
both soft and hard bifurcations are significant network upgrades. However, soft fork allows users who are not upgraded to communicate with upgraded users, while hard fork is not backward compatible with previous versions
as developers realize that deploying soft forks will expose the network to distributed denial of service (DDoS) attacks, Ethereum community decides to initiate hard forks to recover the funds lost in Dao hacking attacks
although this scheme is supported by most people, a small number of people in Ethereum community oppose it. They think that "code is the law" and blockchain network should be unchangeable
the failure of both sides to reach an agreement on the solution eventually led to the fragmentation of Ethereum blockchain
those who tried to recover the lost eth chose the hard fork and opened the Ethereum (ETH) blockchain as we know it today, while another group stayed on the original Ethereum classic (etc) chain
what problems does ethereal classic solve Ethernet classic (etc) is a blockchain platform that allows developers to deploy smart contracts and dapps although this function is the same as Ethereum (ETH), etc blockchain has two main differences first of all, Ethereum classic community opposes tampering with distributed ledger and supports the view that "blockchain network cannot and should not be modified" secondly, although there is no rigid upper limit on the total supply of eth, it is allowed to create 230 million etc at most by adopting the monetary policy of constant supply as a bonus item, ethereal classic launched Atlantis hard bifurcation last year to increase the interaction with Ethereum and improve the privacy protection of transactions through ZK snarks the trading platforms recommended by ethereal classic etc are: Fire coin, okex, AAX, etc
blockchain originates from the underlying technology of bitcoin and is the blockchain technology of Internet. IP is connected by blockchain technology to form distributed accounting. It is not easy to tamper with and decentralize
code chain technology is the code chain technology of the Internet of things, which superimposes the Internet of things IDS one by one in a two-dimensional way to form personal records. The application of "code chain" technology will bring more efficient link forms of "people to people", "people to things" and "things to things"
Introction to code chain:
"code chain" refers to a "two-dimensional code chain" formed by using a smart phone to aim at the "two-dimensional code" and "scan", that is, to "generate a new two-dimensional code containing the scanner's DNA" and access to the "service". The whole process can be traced, supervised and managed
"code chain technology" is the most widely used two-dimensional code "scan" payment technology
code chain technology can realize more efficient link form of people to people, people to things and things to things
Introction to blockchain:
blockchain is an important concept of bitcoin. Blockchain is a series of data blocks generated by cryptography. Each data block contains the information of a bitcoin network transaction, which is used to verify the validity of the information (anti-counterfeiting) and generate the next block
in a narrow sense, blockchain is a kind of chain data structure that combines data blocks in chronological order in a sequential way, and it can not be tampered with and forged by cryptography
broadly speaking, blockchain technology is a new distributed infrastructure and computing paradigm, which uses blockchain data structure to verify and store data, uses distributed node consensus algorithm to generate and update data, uses cryptography to ensure the security of data transmission and access, and uses intelligent contract composed of automated script code to program and operate data
the difference between code chain digital currency and blockchain digital currency:
the difference between "code chain digital currency" based on code chain technology and the existing blockchain digital currency is that "code chain digital currency" is based on the control of property rights, and uses "intelligent two-dimensional code" as the medium to transform the contracts of various instry chains into divisible, tradable, transferable, exchangeable Traceable "smart contract" and real right exchange within the code chain alliance. In the code chain monetary system, "intelligent two-dimensional code" means "SGR". That is to say, each commodity corresponds to a "smart QR code", and this "QR code" represents the "special reference property" of the commodity. Through special reference to the exchange of property rights, the exchange of goods (barter) can be realized. This two-dimensional code, which represents "special mention of property rights", can be used as the carrier and payment means of digital currency at the same time, and payment can be completed through "two-dimensional code scanning".
asymmetric encryption algorithm is a function that converts the original plaintext file or data into a series of unreadable ciphertext codes by using an encryption key. The encryption process is irreversible. Only holding the corresponding decryption key can the encrypted information be decrypted into readable plaintext. Encryption enables private data to be transmitted through the public network under the condition of low risk, and protects the data from being stolen and read by the third party
the core advantage of blockchain technology is decentralization, which can realize point-to-point transaction, coordination and cooperation based on decentralized credit in a distributed system without mutual trust by means of data encryption, time stamp, distributed consensus and economic incentive, so as to solve the high cost and low cost of centralized institutions Low efficiency and data storage insecurity provide solutions
the application fields of blockchain include digital currency, token, finance, anti-counterfeiting traceability, privacy protection, supply chain, entertainment, etc. with the popularity of blockchain and bitcoin, many related top domain names have been registered, which has a great impact on the domain name instry.
1. Blockchain is the core technology of bitcoin's original creation. Before bitcoin was invented, there was no blockchain in the world
2. After the invention of bitcoin, many people refer to the blockchain implementation in bitcoin and use similar technologies to realize various applications, which are collectively referred to as blockchain technology. Including the birth of all kinds of high-quality coins on the coin easy platform, it is the same reason
now the building owner will see if his questions are immediately clear.
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 />