[Paper Review] Blockchain Inefficiency in the Bitcoin Peers Network

Giuseppe Pappalardo, Tiziana Di Matteo+2 more|arXiv (Cornell University)|Apr 5, 2017

Blockchain Technology Applications and Security5 references6 citations

TL;DR

This study analyzes Bitcoin network dynamics over a 7-day period, revealing that 43% of transactions remain unrecorded in the blockchain after one hour and 20% after 30 days, indicating systemic inefficiency. Despite low-value transactions dominating the delay, 93% of transaction value is included within 3 hours, suggesting the core issue lies in weak incentives for miners to prioritize transaction recording rather than block size limitations.

ABSTRACT

We investigate Bitcoin network monitoring the dynamics of blocks and transactions. We unveil that 43\% of the transactions are still not included in the Blockchain after 1h from the first time they were seen in the network and 20\% of the transactions are still not included in the Blockchain after 30 days, revealing therefore great inefficiency in the Bitcoin system. However, we observe that most of these `forgotten' transactions have low values and in terms of transferred value the system is less inefficient with 93\% of the transactions value being included into the Blockchain within 3h. The fact that a sizeable fraction of transactions is not processed timely casts serious doubts on the usability of the Bitcoin Blockchain for reliable time-stamping purposes and calls for a debate about the right systems of incentives which a peer-to-peer unintermediated system should introduce to promote efficient transaction recording.

Motivation & Objective

• To investigate the efficiency of transaction recording in the Bitcoin blockchain by monitoring real-time network dynamics.
• To identify whether transaction delays stem from network congestion, block size limits, or incentive structure flaws.
• To assess the impact of transaction value and fees on inclusion latency in the blockchain.
• To evaluate the feasibility of Bitcoin as a reliable time-stamping system given observed inefficiencies.

Proposed method

• The authors monitored Bitcoin peer-to-peer network traffic for 7.5 days (May 2016), tracking transaction propagation and block inclusion.
• They recorded the time from first network observation to final inclusion in a valid blockchain block for 1,820,212 transactions.
• The team analyzed transaction inclusion latency in seconds and blocks, comparing empirical distributions to exponential decay models.
• They computed cumulative fractions of transactions and total value included in the blockchain over time, distinguishing by transaction value and fee.
• Statistical analysis compared transaction delay distributions, particularly focusing on low-value vs. high-value transactions.
• The study evaluated the role of transaction fees in influencing inclusion speed, contrasting with observed anomalies.

Experimental results

Research questions

• RQ1 What proportion of Bitcoin transactions remain unrecorded in the blockchain after one hour and 30 days?
• RQ2 To what extent does transaction value influence the likelihood of timely inclusion in the blockchain?
• RQ3 How do transaction fees correlate with inclusion latency, and do they serve as effective incentives for miners?
• RQ4 Is the observed inefficiency in transaction recording due to network congestion or block size limits, or is it rooted in incentive design?
• RQ5 Can Bitcoin be reliably used for time-stamping, given the high fraction of delayed or unrecorded transactions?

Key findings

• 43% of transactions were still not included in the blockchain one hour after their first appearance in the network.
• 20% of transactions remained unrecorded after 30 days, indicating severe inefficiency in transaction recording.
• Despite high delay rates for individual transactions, 93% of total transaction value was included in the blockchain within 3 hours.
• The majority of delayed transactions were low-value, with the tail of the delay distribution dominated by small-value transfers.
• Transaction fees showed no strong correlation with inclusion speed, as high-fee transactions were sometimes delayed and low-fee ones processed quickly.
• The inefficiency is not due to network saturation or block size limits, as average block usage was only 0.8MB, with 3% exceeding 0.99MB.