If you’re planning a double-spend attack on Bitcoin, you’d make more money investing in lottery tickets. New research indicates that the Bitcoin (BTC) network is now more secure than ever before.
Analysts from crypto-asset investment firm ID Theory have calculated that Bitcoin’s Proof-of-Work Equivalent Days – which measures the resilience of PoW blockchains- hit a record high in late June, following seven months of near-uninterrupted growth.
The metric represents how long it would take to re-mine a blockchain, based on the total hashrate when each block was originally mined. Based on the ratio of total work to the estimated historical hashrates, ID Theory found that it would take you approximately 450 days to rewrite the entire decade-long history of the Bitcoin blockchain, and that’s assuming you control 100% of the hash power.
“The Proof of Work Equivalent Days is simply another insight into Bitcoin’s security resilience,” explained Lewis Harland, an analyst at ID Theory. After breaching the previous all-time high of approximately 350 days back in February, today’s news demonstrates a long-term trend of increasing Bitcoin security.
A rise in network security tends to coincide with increasing prices. Both figures rose during the 2013 rally – where Bitcoin first pushed past $1,000 – before dropping precipitously at the end of the year. A similar pattern emerged in mid-2016 – when Bitcoin started moving back towards the $1,000 mark.
But this isn’t always the case, and PoW Equivalent Days actually decreased to a three-year low when Bitcoin hit $20,000 – its highest valuation to date.
Although not as popular as other metrics, it has been around for a number of years. Bitcoin fund Adamant Capital was one of the main proponents of this resilience metric, using it from at least 2017; Blockstream co-founder Pieter Wuille has reportedly been using it since late 2016.
Bitcoin Resilience Metric: Proof of Work Equivalent Days.
Amount of time it would take for an attacker with 100% of the hashrate to rewrite the entire blockchain. (total work / hashrate at the time) Src: https://t.co/i9rbZyuv5a pic.twitter.com/hNhY97PpkZ
— Tuur Demeester (@TuurDemeester) December 13, 2017
For Bitcoiners, a key advantage is that PoW-ED supports Bitcoin’s claim to be a superior store of value. A high equivalent days score means users can securely exchange value, without risk of the network shutting down or being taken over by a single entity.
Security on the Bitcoin network has improved considerably. In 2014, a single entity with all the hash power could have effectively rewritten the entire network in as little as forty-five days. That means Bitcoin is now ten times as secure as it was five years ago.
“Bitcoin is generally demonstrating new highs in security resilience every 3 years,” adds Harland. It might also be a key characteristic for long term investors; several PoW blockchains, like Ethereum Classic (ETC), suffered market losses after 51% attacks.
However, that doesn’t mean network security will increase forever. Bitcoin security could be impacted by the next block reward halving, which is expected in Q2 of 2020. Depending on future mining trends, this might be the high water mark for network security until 2022.