What characteristic of blockchain technology makes it resistant to data alteration?

Blockchain technology is inherently resistant to data alteration due to its decentralized nature. In a blockchain, data is stored across a network of nodes, rather than being managed by a central authority. Each node maintains a copy of the entire blockchain, which includes a historical record of all transactions. When a new transaction is created, it is added to a block that is linked to previous blocks, forming a chain.

This decentralized structure means that for any data to be altered, an attacker would need to change the information on every single copy of the blockchain across all participating nodes. This is highly impractical, especially as the size of the network grows and more nodes maintain copies of the blockchain. Additionally, the consensus mechanism used in blockchain technology (such as proof of work or proof of stake) ensures that multiple participants must validate and agree on any changes before they are accepted, further reinforcing the integrity of the data.

While encryption and peer approvals play roles in securing data and validating transactions, it is the decentralized manner of recording transactions that fundamentally establishes the robustness of blockchain against data manipulation.