About the hot blockchain Technology
1. Distributed Storage
Distributed storage is a data storage technology that uses the disk space on each machine in an enterprise through the network and makes these scattered storage resources a virtual storage device, scattered data is stored in every corner of the enterprise.
A Distributed ledger is a database that is shared, copied, and synchronized between network members. A Distributed ledger records transactions between network participants, such as exchange of assets or data.
- Participants in the network restrict and negotiate updates to records in the ledger based on consensus principles. No intermediate third-party arbitration institution (such as a financial institution or a ticket Exchange Institution) is involved.
- Each record in the distributed ledger has a timestamp and a unique password signature, which makes the ledger an audit history record for all transactions on the network. One of the implementations of distributed ledger technology is the open-source hyperledgerfabric blockchain.
Shared ledger
? Blockchain is a shared ledger technology that allows all participants in the Business Network to view the ledger content.
? The ledger provides a verifiable history of all successful status changes. The ledger includes shared, replicated, and permissioned. Multiple accounts correspond to multiple added business networks.
? Transactions-an asset is transferred to or under a ledger. For example, Mr. Smith gave Mr. Zhang a car.
? Contract-conditions for the occurrence of transactions, for example, if Mr. Zhang gives Mr. Smith money, then the car should be given to Mr. Zhang from Mr. Wang. If the car cannot be used, the money will not be on Mr. Wang's account.
Ii. Consensus Algorithms
If multiple users share a ledger, which of the following statements shall prevail?
Consensus algorithm name centralization delay/throughput consistency applicable to blockchain scenario remarks
The practical Byzantine fault tolerance (pbft) is partially decentralized, and the decision-making role (no leader) is preset. Low/low/high. All protocols after N/A are essentially improved by Byzantine fault tolerance. How can several generals reach an agreed decision under the condition of a certain number of traitors, that is, how can a distributed system achieve State consistency in some trusted environments?
Paxos/Raft paxos allows multiple leaders. raft has a single low/high leader, which eventually converges the private chain and has a high trust level. The Consortium chain simplifies the Byzantine general problem and eliminates the existence of Byzantine nodes, only consider the status consistency problems when the nodes fail to communicate normally due to network interruptions, system crashes, and other reasons.
Workload proof
Proof-of-work (POW) fully decentralized high/Low Probability Convergence public chain first consensus algorithm that can reach a state consensus in a completely untrusted network environment; A large amount of computing resources are required. security depends on the sum of computing resources of honest nodes in the network.
Proof of ownership
Proof-of-stake (POS) Owners of more shares have great rights, there may be a tendency to center/dependency implementation depending on the public chain, and the consortium chain overcomes the disadvantages of wasting a lot of computing power on pow. The basic principle of POS is to use part of the resources of users in the blockchain system as their credit creden。, so that they can have a greater say in consistent decision-making. For example, the combination of POW and POW can reduce the difficulty of Mining Based on assets; or the largest number of users of the asset can choose to vote for 100 other users as representatives; or each segment is persistently distributed by the shareholders; short-range, long-range, and cost-free countermeasures are required during design.
Typical improvement protocols
(Ripple, stellar, tendermint, etc.) the low/high final convergence consortium chain ripple is an implementation of Byzantine fault tolerance. Each node can trust other nodes according to rules, in each consensus cycle, multiple rounds of voting are performed on unconfirmed TX to determine whether to record them permanently. tendermint can be seen as a combination of POs and pbft; stellar stellar protocol is a classic pbft improvement solution that provides more flexible trust tolerance
Intel poet (elapse time) decentralized low/high final convergence consortium chain uses Intel's trusted execution environment (TEE) to generate random leader and new block based on the chip wait time; all nodes must use Intel chips
Iii. Smart contract
Smart contract is an event-driven, stateful, stored, and running program on the blockchain.
Iv. Security and Privacy Technologies
- How can we prevent distributed ledger forgery?
-Using digital signatures to forge a single transaction of another person is very difficult, unless you can obtain the private key of another person's digital certificate
-In addition, the distributed ledger can prevent the following types of tampering:
? Delete transaction history
? Forge your own transaction history
- How to protect privacy?
? Make sure that the transaction is visible to only the limited owner, and do not disclose the non-authorized owner.
? To put it simply, use the "Public Key" of the authorized user to encrypt "data". Only authorized users can use their own "Private Key" to decrypt data.
? In practice, symmetric encryption and public key encryption are combined.
- How to protect transaction privacy and implement supervision
? "Regulation" means that regulators can decrypt transactions without the authorization of the transaction party
? However, regulatory authorities cannot infringe "Non-repudiation", that is, regulators cannot forge others' transactions.
? The "two-key pair-signature key pair and encryption key pair" mode of the PKI system is used for implementation:
-The certificate holder has a pair of key pairs for signature purposes.
-The certificate holder has an encrypted key pair.
-When a ca issues a certificate, it must file the key pair for encryption purposes and store it in the key management center.
In specific circumstances, extract a user's decryption private key and decrypt the relevant transaction data
-The key pair used by the signature is still generated on the user end without Record Filing
In the case of private keys, signatures cannot be forged, and therefore others' transactions cannot be forged.
From Certificate Application to certificate generation, the Ca/RA System in the general sense can ensure the privacy of signature key users.
- How to protect privacy?
? Ensure that the information of the transaction creator cannot be traced from the transaction
-Problem
Because there is signature information in the transaction, the signature information carries information that can be associated with the certificate of the transaction creator.
The certificate contains the recognition information of the transaction creator.
If no specific mechanism is implemented, the transaction will be able to trace the information created by the transaction.
? The transaction party holds multiple types of certificates. The following types of certificates will be used in different stages of the transaction:
E-Cert (enrollment Cert)
Hold, carry, or trace user information for a long time
Used for Identity Authentication
T-Cert (transaction Cert)
The signature generated for each transaction.
TLS-cert, long-held, mainly used for SSL/TLS Communication
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About the hot blockchain Technology
