区块链不对称加密算法有哪些,区块链不对称加密算法是什么

区块链不对称加密算法是一种安全性极高的加密算法，它可以将明文转换为密文，以保护网络数据传输的安全性。目前，常见的区块链不对称加密算法有RSA、DSA、ECDSA等。

RSA算法：RSA（Rivest-Shamir-Adleman）是一种非对称加密算法，它使用一对公钥和私钥对数据进行加密和解密。RSA算法可以用来加密少量的数据，并且由于它的安全性，它被广泛应用于区块链系统中。RSA算法的特点在于，它可以非常安全地保护用户的数据，并且它的加解密速度也非常快，适用于大量数据的加解密。

DSA算法：DSA（Digital Signature Algorithm）是一种非对称加密算法，它使用一对公钥和私钥对数据进行加密和解密。DSA算法的特点在于，它可以非常安全地保护用户的数据，并且它的加解密速度也非常快，适用于大量数据的加解密。DSA算法的优势在于它可以防止数据被篡改，而且它可以根据数字签名验证数据的可靠性。

ECDSA算法：ECDSA（Elliptic Curve Digital Signature Algorithm）是一种基于椭圆曲线密码学的数字签名算法，它使用一对公钥和私钥对数据进行加密和解密。ECDSA算法的特点在于，它可以非常安全地保护用户的数据，而且它的加解密速度也非常快，适用于大量数据的加解密。ECDSA算法的优势在于它可以防止数据被篡改，而且它可以根据数字签名验证数据的可靠性。

总之，区块链不对称加密算法是一种非常安全的加密方式，它可以有效地保护网络数据传输的安全性。RSA、DSA和ECDSA算法都是目前常见的区块链不对称加密算法，它们都具有高安全性、快速加解密和防止数据被篡改的优势，是区块链系统中的重要保护技术。

Ⅰ How does blockchain ensure the security of data in the network?

How does blockchain ensure the security of data in the network:
In blockchain Among the technologies, digital encryption technology is the key. Generally, the asymmetric encryption algorithm is used, that is, the password for encryption and the password for unlocking are different. To put it simply, we have an exclusive private key. As long as we protect our private key and give the public key to the other party, the other party will use the public key to encrypt the file to generate ciphertext, and then pass the ciphertext to you, and we will use the private key. Decrypting the plain text can ensure that the transmission content is not seen by others. In this way, the encrypted data transmission is completed!
At the same time, there is also a digital signature that adds an extra layer of protection for us to prove that the document has not been tampered with during the process of sending it to the other party. It can be seen that the encryption technology of blockchain can effectively solve the security problems in the process of data circulation and sharing, which can be said to have great potential. Luanhe

II What are the core technologies of blockchain system development-blockchain transaction system development-

Blockchain technology is an emerging technology today, but so to speak It’s not quite appropriate, because this technology was born with the emergence of Bitcoin ten years ago, but it is okay to say that it is a very hot technology now. After 10 years of continuous updates, blockchain technology has finally seen relevant applications in the past two years, and has entered the blockchain 3.0 era. In the next 3-5 years, I believe there will be more fields that require blockchain Chain system to support. Below, the editor of blockchain system development loopodo will take you to take a look at several core technologies for blockchain system development.
1. Hash algorithm
Hash algorithm is the most commonly used algorithm in the development of blockchain systems. Hash function is also called hash function or hash function. The hash function can convert data of any length into a set of fixed-length codes through the Hash algorithm. The principle is based on a cryptographic one-way hash function. This function is easy to verify, but difficult to crack. Usually, the industry uses y =h (x) to represent it. This hash function implements operations on x to calculate a hash value y.
2. Asymmetric encryption algorithm
Asymmetric encryption algorithm is a secret key method. Asymmetric encryption algorithm requires two keys: public key and private key. . The public key and the private key are a pair. If the public key is used to encrypt data, it can only be decrypted with the corresponding private key. Because encryption and decryption use two different keys, this algorithm is called an asymmetric encryption algorithm
3. Consensus Mechanism
The so-called "consensus mechanism" is through the voting of special nodes. The verification and confirmation of the transaction can be completed in a very short time; for a transaction, if several nodes with unrelated interests can reach a consensus, we can think that the entire network can also reach a consensus on it.
TodayThe consensus mechanism of the blockchain can be divided into four major categories: Proof of Work (PoW), Proof of Stake (PoS), Delegated Proof of Shares (DPoS) and Pool verification pool.
4. Smart Contract
A smart contract is a digital, networked version of a traditional contract. They are computer programs that run on the blockchain and can execute themselves when conditions written in the source code are met. Once a smart contract is written, it can be trusted by users and the terms of the contract will not be changed. Therefore, the contract is immutable and cannot be modified by anyone.
Developers write code for smart contracts, which are used for transactions and any exchange between two or more parties. The code will contain some conditions that trigger automatic execution of the contract. Once written, the smart contract is automatically uploaded to the network. Once the data is uploaded to all devices, users can come to agreement with the results of executing the program code.
5. Distributed Storage
Distributed storage uses the disk space on each machine in the enterprise through the network, and combines these dispersed storage resources into a virtual storage device, and the data is dispersedly stored in Every corner of the enterprise. Massive data is divided according to the degree of structure, and can be roughly divided into structured data, unstructured data, and semi-structured data.
Lupda Network Technology focuses on blockchain system development, Ethereum development, blockchain transaction system development, virtual currency platform development, currency transaction system development, and digital currency wallet system development

Ⅲ Six Core Algorithms of Blockchain Technology

Six Core Algorithms of Blockchain Technology
Blockchain Core Algorithm 1: Byzantine Agreement
The story of Byzantium probably goes like this : The Byzantine Empire had huge wealth, and the 10 neighboring countries around it had been around for a long time. However, the Byzantine wall stood tall and was impregnable, and no single neighbor could successfully invade. Any invasion by a single neighbor will fail, and it is also possible that it will be invaded by 9 other neighbors. The Byzantine Empire's defensive capabilities were so strong that at least half of its ten neighbors had to attack at the same time to be able to break through. However, if one or several of the neighbors agree to attack together, but betrayal occurs during the actual process, then the invaders may all be annihilated. So each party acted cautiously and did not dare to trust its neighbors easily. This is the Byzantine Generals Problem.
In this distributed network: each general has a message ledger that is synchronized with other generals in real time. The signature of each general in the ledger can be used to verify the identity. If any of the messages are inconsistent, you can know which generals the messages are inconsistent with. Even if there is inconsistent information, as long as more than half agree to attack, the minority obeys the majority, and a consensus is reached.
Thus, in a distributed system, although there are bad guys, bad guys can do anything (not restricted by the protocol), such as not responding, sending error messages, sending different decisions to different nodes, and combining different wrong nodes. Get up and do bad things, etc.. However, as long as most people are good people, it is entirely possible to achieve consensus in a decentralized manner
Blockchain Core Algorithm 2: Asymmetric Encryption Technology
In the above Byzantine Agreement, if one of the 10 generals Several messages initiated at the same time will inevitably cause chaos in the system, causing each to have its own attack time plan, making it difficult to act in a consistent manner. Anyone can initiate offensive information, but who will send it? In fact, this only requires adding a cost, that is: only one node can spread the information within a period of time. When a node sends a unified attack message, each node must sign and stamp the message from the initiator to confirm their identity.
It seems today that asymmetric encryption technology can completely solve this signature problem. The asymmetric encryption algorithm uses two different keys for encryption and decryption. These two keys are the "public key" and "private key" that we often hear. Public keys and private keys generally appear in pairs. If a message is encrypted with a public key, the private key corresponding to the public key is required to decrypt it; similarly, if a message is encrypted with a private key, the public key corresponding to the private key is required to decrypt it.
Blockchain Core Algorithm Three: Fault Tolerance Issue
We assume that in this network, messages may be lost, damaged, delayed, sent repeatedly, and the order received is inconsistent with the order sent. In addition, the behavior of nodes can be arbitrary: they can join and exit the network at any time, they can discard messages, forge messages, stop working, etc. Various human or non-human failures may also occur. Our algorithm provides excellent fault tolerance for a consensus system composed of consensus nodes. This fault tolerance includes both security and availability, and is applicable to any network environment.
Blockchain core algorithm 4: Paxos algorithm (consensus algorithm)
The problem solved by the Paxos algorithm is how a distributed system can reach agreement on a certain value (resolution). A typical scenario is that in a distributed database system, if the initial state of each node is consistent and each node performs the same sequence of operations, then they can finally obtain a consistent state. In order to ensure that each node executes the same command sequence, a "consistency algorithm" needs to be executed on each instruction to ensure that the instructions seen by each node are consistent. A general consensus algorithm can be applied in many scenarios and is an important issue in distributed computing. There are two models for node communication: shared memory and message passing. The Paxos algorithm is a consensus algorithm based on the message passing model.
Blockchain Core Algorithm Five: Consensus Mechanism
The blockchain consensus algorithm is mainly proof of work and proof of equity. Taking Bitcoin as an example, in fact, from a technical point of view, PoW can be regarded as reused Hashcash. Generating proof of work is a random process in terms of probability. To mine a new confidential currency, when generating a block, all participants must agree, and the miner must obtain PoW proof of work for all data in the block. At the same time, miners must constantly observe and adjust thisThe difficulty of the work is because the network requirement is to generate a block every 10 minutes on average.
Blockchain Core Algorithm 6: Distributed Storage
Distributed storage is a data storage technology that uses the disk space on each machine through the network and combines these dispersed storage resources into a virtual Storage devices, data are dispersedly stored in every corner of the network. Therefore, distributed storage technology does not store complete data on each computer, but splits the data and stores it in different computers. It's like storing 100 eggs, not in the same basket, but in different places. The total sum is 100.

Ⅳ What are the core blockchain technologies of blockchain technology?

What is the hottest Internet topic at the moment? You don’t need to tell me what the editor is saying, it is blockchain. Blockchain technology, but many friends have only heard of this technology and do not have much in-depth understanding of it. So what are the blockchain technologies? Below we will bring you an introduction to the core technology of blockchain for your reference.
What are the core elements of blockchain technology?
Blockchain technology, which can be a public ledger (visible by anyone) or a permissioned network (visible only by those authorized), solves supply chain challenges , because it is an immutable record that is shared among network participants and updated in real time.
Blockchain technology----data layer: designing the data structure of the ledger
Core technology 1. Block + chain:
Technically speaking, block is a data structure that records transactions. Reflects the flow of funds for a transaction. The blocks of transactions that have been reached in the system are connected together to form a main chain, and all nodes participating in the calculation record the main chain or part of the main chain.
Each block consists of a block header and a block body. The block body is only responsible for recording all transaction information in the previous period, mainly including the number of transactions and transaction details; the block header encapsulates the current version number, previous A block address, timestamp (recording the time when the block was generated, accurate to the second), random number (recording the value of decrypting the answer to the math question related to the block), the target hash value of the current block, and the Merkle number Root value and other information. From a structural point of view, most functions of the blockchain are implemented by the block header.
Core technology 2. Hash function:
The hash function can convert data of any length into a set of fixed-length codes through the Hash algorithm. The principle is based on a cryptographic one-way hash function. This kind of function is easy to verify, but difficult to crack. Usually, the industry uses y=hash(x) to represent it. This hash function implements operations on x to calculate a hash value y.
Commonly used hash algorithms include MD5, SHA-1, SHA-256, SHA-384 and SHA-512, etc. Taking the SHA256 algorithm as an example, inputting any string of data into SHA256 will result in a 256-bit Hash value (hash value). Its characteristics: the same data input will get the same result. As long as the input data changes slightly (for example, a 1 becomes a 0), a completely different result will be obtained, and the result cannot be predicted in advance. Forward calculation (calculating the corresponding Hash value from the data) is very easy. Reverse calculation (cracking) is extremely difficult and is considered impossible under current technological conditions.
Core technology 3. Merkle tree:
Merkle tree is a hash binary tree, which can be used to quickly verify the integrity of large-scale data. In the blockchain network, the Merkle tree is used to summarize all transaction information in a block, and ultimately generates a unified hash value of all transaction information in the block. Any change in transaction information in the block will cause Merkle tree changes.
Core technology 4. Asymmetric encryption algorithm:
Asymmetric encryption algorithm is a key secret method that requires two keys: public key and private key. The public key and the private key are a pair. If the public key is used to encrypt data, only the corresponding private key can be used to decrypt it, thereby obtaining the corresponding data value; if the private key is used to sign the data, then only the corresponding public key can be used to sign the data. In order to verify the signature, the sender of the verification information is the holder of the private key.
Because encryption and decryption use two different keys, this algorithm is called an asymmetric encryption algorithm, while symmetric encryption uses the same key in the encryption and decryption processes.
Blockchain technology----network layer: realize the decentralization of accounting nodes
Core technology 5. P2P network:
P2P network (peer-to-peer network), also known as point-to-point technology, is no Central server, Internet system that relies on user groups to exchange information. Unlike a centralized network system with a central server, each client in a peer-to-peer network acts as both a node and a server. Domestic Xunlei software uses P2P technology. The P2P network has the characteristics of decentralization and robustness.
Blockchain technology----Consensus layer: allocate the task load of accounting nodes
Core technology 6. Consensus mechanism:
Consensus mechanism is how to reach consensus among all accounting nodes to identify The validity of a record is both a means of identification and a means of preventing tampering. There are currently four main types of consensus mechanisms: PoW, PoS, DPoS and distributed consensus algorithms.
PoW (Proof of Work, proof of work): PoW mechanism, which is like Bitcoin’s mining mechanism, miners package existing transactions that have not been recorded by the network into a block, and then continue to traverse and try to find a random number , so that the hash value of the new block plus the random number meets certain difficulty conditions. Finding a random number that meets the conditions is equivalent to determining the latest block of the blockchain, and is also equivalent to obtaining the current round of accounting rights of the blockchain. The miners broadcast the block that meets the mining difficulty conditions in the Yuanfu network, and other nodes in the entire network verify that the block meets the mining difficulty conditions and that the transaction data in the block complies with the protocol.After standardization, each will link the block to its own version of the blockchain, thereby forming a consensus on the current network status in the entire network.
PoS (ProofofStake, Proof of Stake): PoS mechanism requires nodes to provide proof of a certain number of tokens to obtain a distributed consensus mechanism for competing for blockchain accounting rights. If you rely solely on the token balance to determine the bookkeeper, you will inevitably make the rich win, which will lead to the centralization of bookkeeping rights and reduce the fairness of the consensus. Therefore, different PoS mechanisms use different methods to increase the amount of money based on the proof of equity. The randomness of accounting rights avoids centralization. For example, in the PeerCoin PoS mechanism, the Bitcoin with the longest chain age has a greater chance of obtaining accounting rights. NXT and Blackcoin use a formula to predict the next accounting node. The more tokens you own, the greater the probability of being selected as an accounting node. In the future, Ethereum will also switch from the current PoW mechanism to a PoS mechanism. Judging from the information currently available, Ethereum's PoS mechanism will use nodes to place bets on the next block. The winner of the bet will receive an additional Ethereum currency award. Those who do not win will be deducted Ether coins to reach consensus on the next block.
DPoS (DelegatedProof-Of-Stake, share authorization certificate): DPoS is easy to understand and is similar to the modern corporate board of directors system. The DPoS mechanism adopted by BitShares is that shareholders vote to select a certain number of witnesses. Each witness has two seconds of authority to generate blocks in order. If the witness cannot generate a block within the given time slice, The block generation authority is given to the witness corresponding to the next time slice. Shareholders can replace these witnesses at any time by voting. This design of DPoS makes the generation of blocks faster and more energy-saving.
Distributed Consistency Algorithm: Distributed Consistency Algorithm is based on traditional distributed consistency technology. Among them are Byzantine fault-tolerant algorithms that solve the Byzantine Generals problem, such as PBFT (Byzantine fault-tolerant algorithm). In addition, distributed consensus algorithms (Pasox, Raft) that solve non-Byzantine problems are not explained in this article. This type of algorithm is currently a commonly used consensus mechanism in alliance chain and private chain scenarios.
Taken together, POW is suitable for public chains. If you build a private chain, it is more suitable to use POS because there is no trust problem in verification nodes; and because there are untrustworthy local nodes in the alliance chain, it is more suitable to use DPOS.
Blockchain technology----Incentive layer: Develop a "salary system" for accounting nodes
Core technology 7. Issuance mechanism and incentive mechanism:
Take Bitcoin as an example. Bitcoins are initially rewarded by the system to miners who create new blocks, and this reward is halved approximately every four years. At the beginning, miners were rewarded with 50 Bitcoins for each new block recorded, and this reward is halved approximately every four years. By analogy, by around AD 2140, newly created blocks will no longer receive rewards from the system. By then, the total number of Bitcoins will be approximately 21 million. This is the ratioThe total amount of Bitcoin will not increase indefinitely.
Another source of incentives is transaction fees. When there are no system rewards for newly created blocks, the miners' income will change from system rewards to transaction fees. For example, when you transfer, you can specify 1% of it as a handling fee to be paid to the miner who records the block. If the output value of a transaction is less than the input value, the difference is the transaction fee, which will be added to the incentive for that block. As long as a given amount of electronic currency has entered circulation, the incentive mechanism can gradually be converted to rely entirely on transaction fees, so there is no need to issue new currency.
Blockchain technology----Contract layer: giving the ledger programmable features
Core technology 8. Smart contract:
Smart contract is a set of programmed rules and logic that respond to scenarios. Implemented by decentralized, trusted shared script code deployed on the blockchain. Usually, after the smart contract is signed by all parties, it is attached to the blockchain data in the form of program code, and is recorded in a specific block of the blockchain after being propagated through the P2P network and verified by nodes. Smart contracts encapsulate a number of predefined states and transition rules, scenarios that trigger contract execution, response actions under specific scenarios, etc. The blockchain can monitor the status of smart contracts in real time, and activate and execute the contract by checking external data sources and confirming that specific trigger conditions are met.
The above is what blockchain technologies the editor has brought to you? All content of the introduction to the core technology of blockchain.

IV What are the blockchain technologies?

The concept of blockchain can be said to be very popular. At the Internet Finance Summit, no one said that blockchain technology is out. What is chain technology?

Blockchain technology can be either a public classification (anyone can see it) or a permissioned network (only permissioned people can see it), solving supply chain challenges. Because it is An immutable record, so it is shared among network participants and updated in real time.

Blockchain technology - data layer: Designing the data structure of the account book

Core technology 1. Block_ _;Chain:

Technically, a block is a data structure that records transactions, reflecting the capital flow of the transaction. The transaction blocks that have been reached in the system are connected to form the main chain, and all nodes participating in the calculation are It records the main chain or a part of the main chain.

Each block is composed of a block header and a block body. The block body is only responsible for recording all transaction information in the previous period, mainly including transaction quantity and transaction details. The block header includes The current version number, the previous block address, the timestamp (recording the time when the block was generated, accurate to the second), the random number (recording the answer value to the mathematical question related to decrypting the block), the target hash value of the current block, and the Merkle number Information such as the root value of the source mill. From a structural point of view, most functions of the blockchain are implemented by the block header.

Core technology 2. Hash function:

.

The hash function can convert data of any length from the Hash algorithm to a fixed-length code. The principle isIt is a one-way hash function in cryptography. This function is easy to verify, but difficult to interpret. The industry usually expresses it in the form of y=hash(x). This hash function implements the hash value y of x.

Commonly used hash algorithms include MD5, SHA-1, SHA-256, SHA-384, SHA-512, etc. Taking the SHA256 algorithm as an example, input any data into SHA256 and you will get a 256-bit Hash value (hash value). Column value). Its characteristics: the same data input will get the same result. A slight change in the input data (for example, 1 becomes 0) will get a completely different result. The result is measured. Forward calculation (data calculation corresponding Hash value) Very simple. Reverse calculation is extremely difficult and is considered impossible under current scientific and technological conditions.

Core technology 3. Merkle tree:

Merkle tree is a hash binary tree that can Quickly verify the integrity of large-scale data. In the blockchain network, Merkle It is said that Huizaipan⒌MOXIJICM_erkle trees.

Core technology 4. Asymmetric encryption algorithm:

Asymmetric encryption algorithm is a secret method for keys, which requires keys and Key. The public key and the private key are a pair. If you use the public key to encrypt data, you can only use the corresponding private key to decrypt it to obtain the corresponding data value. If you use the private key to sign the data, you can only use the corresponding public key to verify the signature. The sender of the verification information is the owner of the private key.

Since encryption and decryption use two different keys, the algorithm is called an asymmetric encryption algorithm, while symmetric encryption is used in the encryption and decryption process. The same key.

Blockchain mitigation technology - network layer: achieving centralization of charging nodes

Core technology 5, P2P network:

P2P network (Peer-to-peer network), also known as peer-to-peer technology, is an Internet system without a central server and a user group exchanging information. Unlike a central network system with a central server, each client in the peer-to-peer network is a node and also has the function of a server .Domestic Xunlei software uses P2P technology. The P2P network has the characteristics of centralization and strengthening.

Blockchain technology-consensus layer: allocating the task load of charging nodes

VI Blockchain use How to ensure security?

The blockchain itself solves the problem of large-scale collaboration between strangers, that is, strangers can collaborate with each other without trusting each other. So how to ensure trust between strangers to achieve each other's consensus mechanism? The centralized system uses credible third-party endorsements, such as banks. Banks are regarded as reliable and trustworthy institutions by ordinary people. People can trust banks and let banks resolve real-life disputes. But how does a decentralized blockchain ensure trust?
In fact, blockchain uses the basic principles of modern cryptography to ensure its security.Full mechanism. The knowledge system involved in the field of cryptography and security is very complicated. I will only introduce the basic knowledge of cryptography related to blockchain, including Hash algorithm, encryption algorithm, information digest and digital signature, zero-knowledge proof, quantum cryptography, etc. You can use this lesson to understand how the blockchain using cryptography technology can ensure its confidentiality, integrity, authentication and non-repudiation.
Lesson 7 of the basic course: Basic knowledge of blockchain security
1. Hash algorithm (Hash algorithm)
Hash function (Hash), also known as hash function. Hash function: Hash (original information) = digest information. The hash function can map a binary plaintext string of any length into a shorter (usually fixed-length) binary string (Hash value).
A good hash algorithm has the following 4 characteristics:
1. One-to-one correspondence: The same plaintext input and hash algorithm can always get the same summary information output.
2. Input sensitivity: Even if there is any slight change in the plain text input, the newly generated summary information will change greatly, which is hugely different from the original output.
3. Easy to verify: both the plaintext input and the hash algorithm are public, and anyone can calculate by themselves whether the output hash value is correct.
4. Irreversible: If there is only the output hash value, it is absolutely impossible to deduce the plaintext from the hash algorithm.
5. Conflict avoidance: It is difficult to find two plaintexts with different contents, but their hash values ​​are consistent (collision occurs).
Example:
Hash (Zhang San lent Li Si 100,000, with a loan period of 6 months) = 123456789012
A record of 123456789012 is recorded in the ledger.
It can be seen that the hash function has 4 functions:
Simplifying information
It is easy to understand, and the hashed information becomes shorter.
Identification information
You can use 123456789012 to identify the original information, and the summary information is also called the id of the original information.
Concealed information
The ledger contains a record such as 123456789012, and the original information is concealed.
Verification information
If Li Si deceives when repaying the loan, Zhang San only lent Li Si 50,000, both parties can use the hash value and the previously recorded hash value 123456789012 to verify the original information
Hash (Zhang San lent Li Si 50,000, with a loan period of 6 months) = 987654321098
987654321098 is completely different from 123456789012, which proves that Li Si lied, successfully ensuring that the information cannot be tampered with .
Common Hash algorithms include MD4, MD5, and SHA series algorithms. Nowadays, the SHA series algorithms are basically used in mainstream fields. SHA (Sec.ure Hash Algorithm) is not an algorithm, but a set of hash algorithms. It was originally the SHA-1 series. Now the mainstream applications are SHA-224, SHA-256, SHA-384, and SHA-512 algorithms (commonly known as SHA-2). Recently, SHA-3 related algorithms have also been proposed, such as those used by Ethereum. KECCAK-256 belongs to this algorithm.
MD5 is a very classic Hash algorithm, but unfortunately both it and the SHA-1 algorithm have been cracked, and are considered by the industry to be not secure enough to be used in commercial scenarios. It is generally recommended to use at least SHA2-256 or higher. Safe algorithm.
Hash algorithms are widely used in blockchains. For example, in a block, the next block will contain the hash value of the previous block, and the content of the next block + the hash value of the previous block The hash values ​​are used together to calculate the hash value of the next block, ensuring the continuity and non-tamperability of the chain.
2. Encryption and decryption algorithms
Encryption and decryption algorithms are the core technology of cryptography. They can be divided into two basic types in terms of design concepts: symmetric encryption algorithms and asymmetric encryption algorithms. They are distinguished according to whether the keys used in the encryption and decryption processes are the same. The two modes are suitable for different needs and form a complementary relationship. Sometimes they can also be used in combination to form a hybrid encryption mechanism.
Symmetric encryption algorithm (symmetric cryptography, also known as public key encryption, common-key cryptography) uses the same encryption and decryption keys. Its advantages are high computational efficiency and high encryption strength; its disadvantage is that it needs to be advanced in advance. Shared key, easy to leak and lose the key. Common algorithms include DES, 3DES, AES, etc.
Asymmetric encryption algorithm (asymmetric cryptography, also known as public-key cryptography) is different from the encryption and decryption keys. Its advantage is that it does not need to share the key in advance; its disadvantage is that the calculation efficiency is low. Only short content can be encrypted. Common algorithms include RSA, SM2, ElGamal and elliptic curve series algorithms. Symmetric encryption algorithm is suitable for the encryption and decryption process of large amounts of data; it cannot be used in signature scenarios: and the key often needs to be distributed in advance. Asymmetric encryption algorithms are generally suitable for signature scenarios or key negotiation, but are not suitable for encryption and decryption of large amounts of data.
3. Information Digest and Digital Signature
As the name suggests, information digest is to perform a Hash operation on the information content to obtain a unique summary value to replace the original complete information content. Information summary is the most important use of the Hash algorithm. Utilizing the anti-collision characteristics of the Hash function, information summary can solve the problem that the content has not been tampered with.
Digital signatures are similar to signing on paper contracts to confirm contract content and prove identity. Digital signatures are based on asymmetric encryption.It can be used to prove the integrity of a certain digital content and at the same time confirm the source (or non-repudiation).
We have two property requirements for digital signatures that make them consistent with what we expect from handwritten signatures. First, only you can make your signature, but anyone who sees it can verify its validity; second, we want the signature to be relevant only to a specific file and not to other files. These can all be used to achieve digital signatures through our asymmetric encryption algorithm above.
In practice, we generally sign the hash value of the information rather than the information itself. This is determined by the efficiency of the asymmetric encryption algorithm. Corresponding to the blockchain, the hash pointer is signed. If this method is used, the previous one is the entire structure, not just the hash pointer itself.
4. Zero Knowledge proof
Zero knowledge proof means that the prover makes the verifier believe that a certain assertion is correct without providing any additional information to the verifier.
Zero-knowledge proofs generally meet three conditions:
1. Completeness: a true proof can allow the verifier to successfully verify;
2. Reliability (Soundness): a false proof It is impossible for the verifier to pass the verification;
3. Zero-Knowledge: If it is proved, no information other than the proof information can be learned from the proof process.
5. Quantum cryptography
As the research on quantum computing and quantum communication receives more and more attention, quantum cryptography will have a huge impact on cryptographic information security in the future.
The core principle of quantum computing is to use qubits to be in multiple coherent superposition states at the same time. In theory, a large amount of information can be expressed through a small number of qubits and processed at the same time, greatly increasing the calculation speed.
In this case, a large number of current encryption algorithms are theoretically unreliable and can be cracked, which makes the encryption algorithms have to be upgraded, otherwise they will be broken by quantum computing.
As we all know, quantum computing is still in the theoretical stage and is still far away from large-scale commercial use. However, the new generation of encryption algorithms must take into account the possibility of this situation.

VII What does asymmetric encryption algorithm mean

asymmetric encoding algorithm
Asymmetric encryption algorithm requires two keys: public key (publickey) and private key ( privatekey). The public key and the private key are a pair. If the public key is used to encrypt data, only the corresponding private key can be used to decrypt it; if the private key is used to encrypt the data, then only the corresponding public key can be used to decrypt it.can be decrypted. Because encryption and decryption use two different keys, this algorithm is called an asymmetric encryption algorithm. The basic process of asymmetric encryption algorithm to exchange confidential information is: Party A generates a pair of keys and discloses one of them as a public key to other parties; Party B, who obtains the public key, uses the key to process the confidential information. After encryption, it is sent to Party A; Party A then uses another private key saved by itself to decrypt the encrypted information. On the other hand, Party A can use its own private key to encrypt the confidential information before sending it to Party B; Party B can then use Party A's public key to decrypt the encrypted information.
Party A can only use its private key to decrypt any information encrypted by its public key. Asymmetric encryption algorithms provide better confidentiality and eliminate the need for end users to exchange keys.
Characteristics of asymmetric cryptosystem: The algorithm strength is complex, and security depends on the algorithm and key. However, due to the complexity of the algorithm, the encryption and decryption speed is not as fast as that of symmetric encryption and decryption. There is only one key in the symmetric cryptosystem, and it is non-public. If you want to decrypt, you must let the other party know the key. Therefore, ensuring its security is to ensure the security of the key. The asymmetric key system has two keys, one of which is public, so that there is no need to transmit the other party's key like a symmetric encryption. This way the security is much greater.

Ⅷ What is a blockchain encryption algorithm?

Blockchain encryption algorithm (EncryptionAlgorithm)
Asymmetric encryption algorithm is a function that uses an encryption key to convert the original Convert plain text files or data into a string of unreadable cipher text codes. The encryption process is irreversible. Only by holding the corresponding decryption key can the encrypted information be decrypted into readable plain text. Encryption allows private data to be transmitted through public networks with low risk and protects data from being stolen and read by third parties.
The core advantage of blockchain technology is decentralization. It can realize decentralized credit in a distributed system where nodes do not need to trust each other by using data encryption, timestamps, distributed consensus and economic incentives. Point-to-point transactions, coordination and collaboration, thereby providing solutions to the problems of high cost, low efficiency and insecure data storage common in centralized institutions.
The application fields of blockchain include digital currency, certificates, finance, anti-counterfeiting and traceability, privacy protection, supply chain, entertainment, etc. With the popularity of blockchain and Bitcoin, many related top domain names have been registered. , which has had a relatively large impact on the domain name industry.