Blockchain Developer Certification Practice

What makes blockchain technology inherently secure against tampering?

1. It is encrypted at all stages

2. There are multiple copies distributed across nodes

3. It uses a centralized database

4. It requires physical access to alter

The correct answer is: There are multiple copies distributed across nodes

The inherent security of blockchain technology against tampering primarily stems from the concept of decentralization and distribution. When multiple copies of the same data are distributed across numerous nodes in a network, each copy acts as a form of validation. This distribution means that for any single entity or malicious actor to alter the data on the blockchain, they would need to compromise over half of the nodes simultaneously, which is exceedingly challenging and often practically impossible, especially in large networks. Furthermore, the consensus mechanisms used in blockchains reinforce this security. They require agreements from multiple nodes before changes can be made to the data. As a result, it produces a trustworthy environment where fraudulent modifications to the data can be detected and rejected by other nodes, preserving the integrity of the original dataset. In contrast, encryption, while important, does not alone secure a blockchain from tampering. Similarly, using a centralized database introduces vulnerabilities, as a single point of failure can be exploited by attackers. The requirement of physical access to alter data may apply in some contexts but doesn't encompass the broader, more complex security provided by the distributed architecture inherent in blockchain technology.