Blockchain Timestamps Found Inaccurate in 7.5% of Transactions

Blockchain timestamps, which are integral to the functioning of decentralized ledgers, are sometimes inaccurate. This inaccuracy stems from the peer-to-peer architecture of blockchain networks, which lack a global clock. Miners rely on their own clocks and algorithms to determine the exact time for block timestamps. These timestamps are accepted as long as they are greater than the timestamp of the parent block and no more than two hours into the future. This flexibility can lead to significant discrepancies in timestamps from one miner to another.

An empirical evaluation of blockchain-recorded block timestamps revealed that these timestamps are often inaccurate. In a study, 7.5% of submitted transactions had a block timestamp that was lower than or equal to the transaction submission timestamp. For instance, one transaction submitted at 20:55:58 UTC had a block timestamp of 20:55:56 UTC. This discrepancy indicates that the block timestamp is not a reliable proxy for the processed timestamp. Additionally, 20% of transactions were processed in no more than 7 seconds, which is unlikely given that blocks are appended on average every 15 seconds. This further supports the conclusion that block timestamps are inaccurate.

To obtain more accurate block timestamps, researchers turned to Etherscan, a blockchain explorer. Etherscan updates its front page in real-time when a new block is appended to the blockchain. By monitoring this live list, researchers recorded the timestamp at which a new block appeared. This method reduces the bias introduced by relying on multiple miners' clocks, as Etherscan aims to provide a real-time dashboard with minimal lag between block addition and page update. This approach provides a more accurate processed timestamp, essential for understanding transaction processing times in blockchain networks.

The inaccuracy of blockchain timestamps has significant implications for end-users and developers. For end-users, inaccurate timestamps can lead to misunderstandings about transaction processing times, potentially causing delays or errors in financial transactions. For developers, accurate timestamps are crucial for building reliable applications that depend on blockchain data. The findings highlight the need for more robust methods of timestamping in blockchain networks to ensure accuracy and reliability.