nonce blockchain

. The chunk header is 80 bytes, with an average of at least 250 bytes per transaction, and an average of at least 500 transactions per chunk. Therefore, a complete chunk containing all trades is 1000 times times larger than the chunk head. Table 7-1 describes a block structure. table 7-1 block structure size Field Description 4 bytes Chunk size The chunk size after the field in bytes 80 bytes Block size Several fields that make up

or trust institution endorsement is not required. Non-tampering and encryption security: The blockchain adopts a one-way hash algorithm, and each newly generated block is promoted in strict chronological order, the irreversible nature of time makes any attempt to intrude or tamper with the data in the blockchain easily traceable, leading to rejection by other nodes, thus limiting related illegal behavior

metadata and a long list of transactions immediately following the constituent block body. The chunk header is 80 bytes, with an average of at least 250 bytes per transaction, and an average of at least 500 transactions per chunk. Therefore, a complete chunk containing all trades is 1000 times times larger than the chunk head. Table 7-1 describes a block structure.Table 7-1 block structureSize Field Description4 byte chunk size The chunk size in bytes after the field80-byte chunk header several

Nonce, timestamp--solve replay-attack problem A nonce is a random number generated by the server that is sent back to the client the first time the client requests the page, and the client gets the nonce, concatenates it with the user's password and makes non-reversible encryption (MD5, SHA1, and so on), and then converts the encrypted string and user name,

A: What is a nonceWikipedia : in Security engineering , A Nonce is a number that can only be used once in an encrypted communication. In the authentication protocol, it is often a random or pseudo -random number to avoid replay attacks. II: ExamplesA typical nonce-based authentication protocol is as follows:The cnonce here is the client nonce (which will be discu

I. Background of the problem When a client sends an RPC request to the server, it is likely that, for various reasons, the response times out. If the client is just waiting, the operation against the data, it is likely that the server side has been processed, but unable to notify the client, at this point, the client can only re-initiate the request, but it may cause the service side to duplicate processing requests. How to solve the problem. Second, the solution In fact, after the client sends

It has always been timestamp to prevent replay attacks, but this does not guarantee that each request is one-time. Today I saw an article introduced by nonce (number used once) to ensure an effective, feel the combination of both, you can achieve a very good effect. Replay attack is one of the most common ways for hackers in computer world, so the so-called replay attack is to send a packet that the host has received, in order to achieve the purpose o

Some time ago, I made a Sina Weibo account logon function for the customer's website, and made some research on the OAuth Protocol and related security protocols. By the way, I will record my learning experience. Here, we do not want to talk about the OAuth Protocol process in detail, but for the nonce (random number), timestamp (timestamp), signatrue (Signature) in the OAuth request header) the functions of these parameters are summarized. First, le

phenomenon is that the Nonce value passed when the transaction was sent was incorrect. nonce Use Instructions In order to prevent the transaction replay attack, each transaction must have a nonce random number, for each account nonce is starting from 0, when Nonce 0 of the

created. This is a simple technology that prevents abuse through a certain amount of computing. Workload is the key to preventing spam filling and tampering. If it requires a lot of computing power, it is no longer worthwhile to fill the garbage. Bitcoin requires hash to implement POW with a specific number of zeros. This is also called difficulty. But wait! How can the hash of a block be changed? In the bitcoin scenario, a block contains various financial transaction information. We certainly

block Chain Intro What the blockchain really is. Blockchain (English: Blockchain) is a distributed database, originated from Bitcoin, Blockchain is a series of cryptographic methods associated with the generated data block, each block contains a number of Bitcoin network transactions information, to verify the validi

iterated until the hash value is valid. In our case, a valid hash value is a minimum of 4 leading 0. The process of finding the hash value to meet the appropriate conditions is called mining.The following code is given:Version GolangPackage Mainimport ("bytes" "crypto/sha256" "FMT" "Math" "math/big")//Preamble 0, difficulty const TARGETBITS = 8type Pro ofofwork struct {block *block targetbit *big. Int}func newproofofwork (Block *block) *proofofwork {//Set 64-bit full 1 var inttarget = big. Newi

blockchain and database in ensuring data consistency. All the students who studied the database could not have heard of the lock. When we do a transaction, all records of the session change before committing are locked and cannot be modified by other sessions. In a centralized database, because each ledger node operates local data, the change information is transferred asynchronously, so there is no global lock to notify others when a change is recor

noun Block Chain: Block chain Utxo:unspent Transaction output, non-spent trade outputs Genesis BLOCK: Blocks 0, Genesis block Spv:simplified Payment Verification, simple payment verification Bip:bitcoin improvement proposal, Bitcoin improvement proposal Proof of work: proof of workload block Chain The blockchain provides a public account of Bitcoin, an orderly, time-stamped transaction (transaction) record. The system is designed to prevent recurring

database could not have heard of the lock. When we do a transaction, all records of the session change before committing are locked and cannot be modified by other sessions.In a centralized database, because each ledger node operates local data, the change information is transferred asynchronously, so there is no global lock to notify others when a change is recorded. Therefore, in the absence of a lock on the premise, to the central database, that is, bloc