区块链数字签名非对称什么意思,区块链数字签名非对称怎么弄

区块链数字签名非对称是一种基于密码学的安全技术，它可以将数字信息签名，以确保信息的完整性和真实性。它是一种非常灵活的技术，可以用于不同的行业，如金融、政府、医疗保健等。

区块链数字签名非对称的原理是，它使用一个公钥和一个私钥，将原始数据签名，以确保信息的完整性和真实性。公钥用于签名，私钥用于验证签名，公钥和私钥之间的关系是不可逆的，因此可以确保信息的完整性和真实性。

区块链数字签名非对称有很多优点，首先，它可以提供更高的安全性，因为它是基于密码学的安全技术，公钥和私钥之间的关系是不可逆的，因此可以确保信息的完整性和真实性。其次，它可以更有效地保护用户的隐私，因为它可以提供更强大的加密功能，以保护用户的隐私信息。最后，它可以更有效地防止篡改数据，因为它可以确保数据的完整性和真实性，从而防止篡改数据。

总之，区块链数字签名非对称是一种强大的安全技术，它可以提供更高的安全性，更有效地保护用户的隐私，更有效地防止篡改数据，是一种非常有用的技术。

Ⅰ What are the main data security measures of the supply chain blockchain?

The main data security measures include identity authentication, access control, data encryption, data backup, etc.

II How to ensure the security of using blockchain

Blockchain itself solves the problem of large-scale collaboration between strangers, that is, strangers do not need to trust each other. You can collaborate with 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 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 originalThe id of the message.
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 (Secure 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 encrypted chaptersShorter content. 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 and 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 impossibleYes, it can be cracked, so the encryption algorithm has to be upgraded, otherwise it 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.

Ⅲ What is a digital signature?

Digital signature (also known as public key digital signature, electronic signature) is a kind of ordinary physical signature similar to written on paper, but uses Technical implementation in the field of public key encryption, a method used to authenticate digital information. A set of digital signatures usually defines two complementary operations, one for signing and another for verification.
Digital signature is a digital string that can only be generated by the sender of the information and cannot be forged by others. This digital string is also an effective proof of the authenticity of the information sent by the sender of the information.
Digital signature is the application of asymmetric key encryption technology and digital digest technology.

IV What technology does the blockchain apply to achieve this function?

The blockchain applies the following technologies to achieve this
The first is the consensus mechanism. Commonly used consensus mechanisms are mainly There are PoW, PoS, DPoS, PBFT, PAXOS, etc. Since there is no center in the blockchain system, there needs to be a preset rule to guide the nodes of all parties to reach an agreement on data processing. All data interactions must be carried out in accordance with strict rules and consensus;
The second It is cryptography technology. Cryptography technology is one of the core technologies of blockchain. Many classic algorithms of modern cryptography are used in current blockchain applications, mainly including: hash algorithm, symmetric encryption, asymmetric encryption, digital Signature etc.
The third type is distributed storage. Blockchain is a distributed ledger on a peer-to-peer network. Each participating node will independently and completely store and write block data information. The advantages of distributed storage compared with traditional centralized storage are mainly reflected in two aspects: data information is backed up on each node to avoid data loss due to single point failure; data on each node is stored independently, effectively avoiding Malicious tampering with historical data.
Smart contracts: Smart contracts allow trusted transactions without a third party. As long as one party reaches the pre-set goals of the agreement, the contract will automatically execute the transaction. These transactions are trackable and irreversible. It has the advantages of transparency, credibility, automatic execution, and mandatory performance. Blockchain technology has many unique features that make it a unique invention and give it unlimited horizons to explore.