Blockchain achieves security hardening through a variety of mechanisms, including advanced cryptography and mathematical models of decision-making and behavior. Blockchain technology is the infrastructure of most digital currency systems, and it prevents digital currencies from being copied and destroyed.

The application of blockchain technology is also particularly important in other environments where data cannot be tampered with and security requirements are very high. Examples include recording and tracking charitable donations, medical databases, and supply chain management.

However, the security of blockchain is far from a simple issue. Therefore, it is critical to understand how the basic concepts and mechanisms of these innovative systems provide strong protection for the blockchain.

The concept of immutability and consensus

Although many features of security are related to blockchain connection, but the two most important features are consensus and immutability. Consensus means that nodes in a distributed blockchain network can reach an agreement on the true status of the network and the validity of transactions. The process of reaching consensus often depends on the consensus algorithm used by the network.

On the other hand, immutability means that the blockchain can prevent confirmed transaction records from being changed. While these transactions are often associated with the conversion of digital currency, sometimes they also refer to the recording process of other non-monetary forms of electronic data.

In general, consensus and immutability provide a basic framework for data security in blockchain networks. The consensus algorithm can ensure that all nodes follow the system rules and recognize the current status of the network, and non-tampering can ensure the integrity of each block data and transaction record that has been verified for validity.

The role of cryptography in blockchain security

Blockchain mainly relies on encryption technology to ensure Data security. The cryptographic hash function is the key to this technology. Hashing is a computational process, and a hashing algorithm is an algorithm that can input data of any size and output a predictable and fixed-size hash (i.e., a hash function).

The output is always the same bytes regardless of the size of the input data. But if the input changes, the output will be completely different. As long as the input does not change, no matter how many times you run the hash function, the output hash value will always be the same.

In a blockchain, these output values (i.e. hashes) are unique identifiers for blocks of data. The hash of each block is generated relative to the hash of the previous block, which is what links blocks together to form a blockchain. Additionally, the block hash is determined by the data contained in the block, meaning any changes made to the data will change the block hash.

Therefore, the data of this block and the hash of the previous block together determine the hash of each block. These hash identifiers play an important role in ensuring that the blockchain is secure and cannot be tampered with.

Hash functions are also used in consensus algorithms to verify transactions. For example, on the Bitcoin blockchain, the Proof of Work (PoW) algorithm uses a hash function called SHA-256. As the name suggests, SHA-256 takes input data and outputs a hash value that is 256 bits or 64 characters long.

In addition to providing protection for transaction records in distributed ledgers, cryptography can also play an important role in the security of wallets that store digital currencies. Pairs of public and private keys allow users to receive and send digital currencies using asymmetric or public-key cryptography, respectively. Private keys are used to generate the electronic signatures required for transactions, thereby verifying ownership of the currency being sent.

While the specifics are beyond the scope of this article, the properties of asymmetric cryptography can prevent anyone other than the holder of the private key from accessing funds stored in a digital currency wallet, thereby enabling These funds are kept safe until the owner decides to use them (as long as the private keys are not shared or leaked).

Cryptoeconomics

In addition to cryptography, a comparative approach called cryptoeconomics Novel concepts also play an important role in maintaining the security of blockchain networks. It is closely related to the field of study of game theory, which uses mathematical principles to simulate decisions made by rational actors in situations with established rules and rewards. While traditional game theory can be broadly applied to a range of business cases, cryptoeconomics also independently models and describes the behavior of nodes on distributed blockchain systems.

In short, cryptoeconomics is the study of the economics in blockchain protocols, and their design principles may produce different results based on the behavior of their participants. Cryptoeconomics security is based on the model that blockchain systems provide greater incentives for nodes to act authentically rather than maliciously or mistakenly. Furthermore, the proof-of-work consensus algorithm used in Bitcoin mining is an excellent example of providing this kind of incentive.

When Satoshi Nakamoto proposed the framework for Bitcoin mining, it was intentionally designed to be an expensive and resource-consuming endeavor. Due to its complexity and computational requirements, PoW mining involves a large investment of money and time - regardless of the location of the mining node and the user. Therefore, this structure provides strong protection against malicious activities and encourages honest mining behavior. Malicious or inefficient nodes will quickly be eliminated from the blockchain network, while genuine and efficient miners are likely to receive large block rewards.

Similarly, the balance between risks and benefits can also be achieved by placing the majority of a blockchain network's hashrate in the hands of a single organization or entity to prevent potential attacks that could undermine the consensus. happened. Just like the well-known 51% attack, once successful, it can cause great damage. Given the competition mechanism of proof-of-work and the size of the Bitcoin network, the possibility of a malicious user gaining control of most nodes is very small.

In addition, in a huge blockchain network, the computing power consumed to achieve a 51% attack will be an astronomical figure. Therefore, this huge investment has a relatively small potential return difference. It also directly inhibits the occurrence of the attack. This also contributes to a typical feature of blockchain, namely Byzantine Fault Tolerance (BFT), which illustrates that even if some nodes are compromised or malicious behaviors occur, the distributed system can still continue to work normally.

As long as the cost of generating a large number of malicious nodes is too high and real mining activities can be better incentivized, the system can continue to grow without resistance. However, it is worth noting that relatively small blockchain network systems would be vulnerable to attacks because the total hash rate used for these systems is much lower than that of the Bitcoin network.

Summary

Through the combined use of game theory and cryptography, blockchain can act like a distributed system Still get higher security. However, as with almost all systems, the correct application of these two areas of knowledge is critical. The balance between decentralization and security is crucial to building a reliable and efficient digital currency network.

With the continuous development and promotion of blockchain, its security system will also change to meet the needs of different applications. For example, private blockchains developed for commercial enterprises today rely more on the security provided by access control, which is very different from the game theory mechanisms (or cryptoeconomics) used by most public blockchains.