Nowadays, we use a wide variety of services, from essential utilities like electricity, water, and gas to streaming solutions and social media platforms.
Based on the severity and the services involved, the consequences of a network outage can range from minor (often rather annoying) problems to disastrous crises.
While downtimes at MasterCard and Visa in 2018 made European cardholders unable to pay for products and services for several hours, Texas’s ongoing power crisis has left millions of people in the dark since February 10.
Furthermore, the EU ordered Netflix and other streaming providers last March to reduce their services’ video quality to avoid a network outage at internet service providers due to the increased usage from self-isolating citizens.
For these reasons, network resilience, which refers to providing and maintaining an acceptable level of service in the face of faults and challenges to normal operation, has become increasingly important in the past few years.
Network resilience is also critical for Bitcoin, which has achieved an almost continuous uptime since its inception.
But what is behind the Bitcoin blockchain’s enhanced stability, and can the cryptocurrency’s network maintain the same level of resilience in the future?
Bitcoin and Network Disruptions
Since its launch in January 2009, Bitcoin has been featuring an over 99.986% uptime, which puts the cryptocurrency among the world’s most stable networks.
According to BinaryCanary’s research that monitored 1,000 websites across numerous industries, the average uptime for a site is 99.41%, which means a yearly downtime of 52 hours for each service.
For comparison, Bitcoin has been down in two instances for only 14 hours and 47 minutes during the cryptocurrency’s lifetime. As a result, the BTC network faces a yearly service disruption of one hour and 14 minutes on average.
Bitcoin experienced its first network issue on August 15, 2010 due to a bug, which caused a block to create a transaction with nearly 185 billion BTC for three different addresses.
To fix the issue known as the “value overflow incident,” developers published a new version of the client that contained a soft fork upgrade (a minor update that is compatible with previous versions).
While the soft fork managed to eliminate the bug and cancel the transaction, the Bitcoin network was down for 8 hours and 27 minutes before the upgrade went live.
The second (and the last) time the Bitcoin network was disrupted was in March 2013 when miners running different versions of BTC clients came into a disagreement about a block during the BIP 0050 upgrade.
As a result, a small chain split occurred, which miners fixed by reorganizing themselves onto the same client. The incident lasted 6 hours and 20 minutes.
Despite the two network issues in Bitcoin’s history, they can’t be considered outages, only minor disruptions that were fixed quickly.
How Bitcoin Maintains its Resilience
Even with two minor disruptions, the Bitcoin network has managed to stay resilient, competing with tech giants’ systems, such as Amazon, Google, and Microsoft, in terms of stability.
But what is behind Bitcoin’s network resilience?
Minimizing Outages and Internal Issues
The answer lies in the decentralized architecture of blockchain solutions.
Unlike traditional systems that use a central server to operate the network, Bitcoin’s blockchain is maintained by millions of miners worldwide.
As a result, Bitcoin eliminates the threat of a single point of failure. For that reason, even if a great number of nodes go offline due to a hacker attack or a technical failure, it won’t lead to an outage as the remaining nodes will keep the network operational.
Nodes are physical or virtual devices connected to the network responsible for performing different functions (e.g., validating transactions and adding new blocks to the chain) and acting as communications points (all miners are nodes).
Currently, Bitcoin has over 10,000 active full nodes around the world, according to Bitnodes.io. Interestingly, BTC also operates a node at the International Space Station (ISS), which was used last year to authorize a crypto transaction while orbiting the Earth at 5 miles per second.
Furthermore, to avoid internet-related problems, multiple technologies (such as the Blockstream Satellite) allow Bitcoin nodes to communicate with each other without connecting to the web.
Protecting Against External Threats
All miners in the network share the same version of the distributed ledger while recording all changes in real-time.
Participants can only add new blocks to the chain, verify transactions, or make any changes through consensus, which means that everyone in the network has to come to an agreement.
For that reason, malicious parties have to take over the 51% of the network (called the 51% attack) to tamper with transactions and control the Bitcoin blockchain.
However, since Bitcoin’s hashrate currently stands at 155 million TH/s and continuously grows, it would be too expensive for hackers to carry out such an attack.
11 months ago, when we wrote an article on the topic, the BTC hashrate was at 111 million TH/s. To carry out a successful 51% attack at the time, hackers would have to pay a fixed $2.71 billion fee for acquiring the mining rigs along with covering a weekly cost of $78 million for operating them.
In addition to 51% attacks, the Bitcoin blockchain is extremely resilient against other cyber breaches and fraud schemes, including distributed denial of service (DDoS) and Sybil attacks as well as double-spending.
The only attack type the Bitcoin network (and most blockchain systems) are not currently prepared against are the ones that are carried out via quantum computers.
Quantum computers can do calculations and solve mathematical puzzles extremely fast. For example, it took Google’s quantum machine 200 seconds to perform a calculation that would have needed the world’s (currently) most powerful supercomputer 10,000 years.
For that reason, quantum computers can theoretically break the public-key cryptography Bitcoin and other digital asset networks use to encrypt transactions and other data on the blockchain.
However, while Google achieved a major breakthrough in quantum computing in October 2019, the development in this area is still in a very early stage.
As a result, it would take several years (or even tens of years) for quantum computing to advance to the point in which these advanced machines can break the public-key cryptography of blockchain networks.
Furthermore, as soon as the quantum computing threat becomes more significant in the future, Bitcoin and other cryptocurrencies can implement post-quantum cryptography, which effectively protects their networks against quantum attacks.
Bitcoin Will Be Even More Resilient in the Future
Bitcoin’s decentralized architecture and huge network participation allow the cryptocurrency’s network to stay extremely resilient against both internal issues and external threats while getting closer to a 99.99% uptime.
And we shouldn’t forget that developers and major industry players continuously improve Bitcoin’s resilience and security.
In fact, MIT announced its Digital Currency Initiative’s launch last month to strengthen the BTC network, reinforce the digital asset’s security, and eliminate future vulnerabilities.
Also, Bitcoin has experienced significant demand from institutionals in the past few months. As a result, corporate players hold considerable amounts of BTC along with retail investors.
And the better the distribution, the more entities have their interests tied to Bitcoin’s survival, which will eventually include governments as well to protect their citizens via an effective regulatory framework around crypto.