New study opportunities for blockchain technology

The course in Ireland will encourage young talent and help Ireland to lead the way in blockchain technology, said Minister Heather Humphrey at the launch of the Masters in Dublin. The programme is part of the Irish Government’s Future Jobs Initiative. The initiative aims to anticipate and respond to future labour market demands.

In this context, the Irish government attaches great importance to the development of distributed ledger technology. As part of the National Blockchain Strategy, it launched Ireland Blockchain Week. The publication of the program took place within this week. In developing the course, Technology Ireland ICT Skillnet worked with Blockchain Ireland to find out what skills will be needed in tomorrow’s sector. The course is expected to deliver these skills from September 2019. It is a part-time online course run by experts from industry and Dublin City University.

Wharton School offers financial program with blockchain focus

The Wharton School of the University of Pennsylvania also focuses on the merger of business and educational institutions. Thus the institution reacts according to own data to the fast changing requirements within the range of the financial economy.

The FinTech: Foundations and Applications of Financial Technologies program covers topics such as crypto currencies and blockchain, but also further training in crowdfunding, modern investment and insurance technology is offered. The course is taught by professors from the Penn Faculty and lecturers from the financial sector.

Blockchain courses still popular

New blockchain technology courses are emerging in the education sector worldwide. Brazil recently announced the first master’s degree in blockchain technology. There are also several initiatives and study opportunities in Germany. In the USA, universities such as Duke, Cornell, the Massachusetts Institute of Technology (MIT) and New York University (NYU) offer courses of study.

Bitcoin Enthusiast Sends Diary Over Blockstream Satellite

Blockstream seems to be working. An unknown Bitcoin enthusiast has been sending his diary about the Blockstream satellite for over a week now. What is behind the mysterious figure?

There are simple methods and there are elaborate (but exciting) methods to communicate. A mysterious Bitcoin fan, who appears to be a software developer from the former Soviet Union, has recently made use of the latter option. For a few days now, the anonymous sender has been sending messages through the airwaves to make the hearts of the Bitcoin community beat faster.

The Twitter user @notgrubles first drew attention to the confused figure. Well, the sender had feared that his messages would never find an addressee.

On the seventh day “Post-Soviet Person”, as the discoverer baptized his mysterious friend, did not rest, but stroked a dog puppy.

Bitcoin without Internet
Blockstream already seems to work. The company around founder and Cypherpunk Adam Beck has set itself the task of bringing Bitcoin to the remote regions of the world. The company uses a satellite that synchronizes nodes on the ground with the blockchain – without an Internet connection. The Venezuelan development team around Locha Bitcoin proves that this is not science fiction.

Eight Percent of Ethereum Nodes are in Singapore

Blockchain’s trustworthiness is ensured by the nodes that verify transactions. These nodes, distributed all over the world, help keep digital currencies decentralized. This does not mean, however, that all nodes are distributed equally.

According to February 20 data from Bitnodes, there are 10,464 bitcoin nodes in the world, distributed in 115 countries. Below are the 10 countries with the largest number of Bitcoin nodes.

In these relatively early days in Bitcoin’s history, the distribution of nodes is still concentrated in the United States and Europe. Looking more closely at the data, however, reveals more surprising details. Singapore, which has a population of only 5 million, has 319 bitcoin nodes. That number is not much smaller than the 371 nodes in an enormous country like China.

The node distribution of Ethereum, at least according to data from Etherscan, is even more interesting. 

There are 7,707 Ethereum nodes in the world. The United States still dominates. But Singapore has 632 full nodes, even more than China, which only has 548. Japan and South Korea also make an appearance, demonstrating their status as rising stars of the crypto world. 

Just for fun, we also looked at Tron nodes: https://tron.network/, There are now 1138 nodes. Singapore ranks fifth, with 68 nodes. 

Singapore’s ranking in the top 10 node locations for Bitcoin, Ethereum and Tron are likely related to Singapore’s warm welcome of blockchain technology. Node distribution reflects different countries’ attitudes toward cryptocurrency.

5 things every Bitcoin beginner should know about

No idea about crypto currencies? Doesn’t matter. The following are some of the most important concepts when it comes to Bitcoin and other crypto currencies.

Attention: The following lines neither replace your own research nor want and can they be complete in any way. There are only five concepts from the area of crypto currencies, which everyone should know, who deals with the topic.

FOMO – The Fear of Missing Something

Especially when prices explode – as was last the case at the end of 2017 – people become nervous: “If I had bought yesterday, I would have made a profit”. In the worst case, you can buy any token you want without finding out about it. The concept behind it is called FOMO and stands for the fear of missing something (Fear of Missing Out).

My tip: Take a deep breath and inform.

FUD – Fear, uncertainty and doubt

Just as unhealthy as FOMO. Fear, insecurity and doubt occur when prices suddenly collapse. Then you think: Quickly, I have to sell before things get worse. And if negative headlines are added, for many it’s over very quickly.

HODL, HODL, HODL

The way out of FUD and FOMO: just muddle through. The idea behind it: Simply keep your Bitcoin in your digital wallet instead of selling it in a panic.

My tip: Better than FUD and FOMO, worse than looking at analyses, reading about the topic and making rational decisions. In case of doubt: do it.

Watch out for the shitcoins!

Currently Coinmarketcap lists a total of 2,072 crypto currencies, the number of unreported cases is uncertain. Sometimes you can tell by their names that they are not serious projects. Or would you invest in HollyWoodCoin, TrollCoin or PonziCoin? Hopefully not.

Pump & Dump: In case of doubt, things can happen very quickly

What is prohibited in regulated finance is not a problem in the Bitcoin ecosystem. The principle: Some people agree on a certain time and date, when they put a lot of money into a project in a short time (pump). This drives up the price. Then they wait until others become aware of it and sell their tokens again, the price falls (dump). They mainly rely on FUD, FOMO and Shitcoins. What remains are a few who were able to enrich themselves and many more who are glued. Appointments take place in messengers, mainly telegrams.

My tip: hands off. Otherwise: money away.

Ethereum blockchain to help hurricane victims

The USA, in particular, is repeatedly confronted with severe natural catastrophes such as extreme hurricanes. The east coast is currently preparing for the arrival of “Florence”, a hurricane larger than Germany. In order to accelerate subsequent insurance processes, a Swiss start-up now wants to use the Ethereum blockchain.

In Switzerland, the devastation that a hurricane can cause is only known from the media. The aisles that such a hurricane pulls into the countryside or even into cities testify to the immense destructive rage. After the storm has passed, the insurance industry comes onto the scene. These include insurance agents and agents who are supposed to minimize possible fraud on behalf of insurance companies. But reinsurers, who protect insurance companies, and retrocessionaires, who in turn serve reinsurance companies, are also involved in the processes that trigger such natural disasters.

Minimizing post-disaster chaos
The surviving victims of natural disasters are often dependent on rapid assistance. Especially for those who have literally lost their roof over their heads, any delay in the insurance process means another catastrophe. Due to the complicated insurance system, in which a lot of time is spent checking the actual damage, it can often take weeks or even months before sums insured are paid out.

The Swiss blockchain start-up Etherisc has now set itself the goal of defusing this insurance chaos so that the injured parties can receive help more quickly. To this end, it wants to shift the insurance workflow to a common, distributed ledger of transactions and enable the automatic payment of certain types of support.

Etherisc was founded in 2017 as an open source platform. The start-up is dedicated to the creation of insurance products with the Ethereum blockchain. Having raised $3.6 million through its ICO, Etherisc is already helping other companies create insurance policies that use smart contracts. The blockchain is mainly used to store numerous data such as wind speed or cancelled flights tamper-proof. In this way, they can be made available for automatic payment processes.

First cooperation in Puerto Rico
Puerto Rico’s InsurTech start-up HurricaneGuard is already using Etherisc technology, Forbes reported on September 11. In order to minimize the suffering of victims like those of Hurricane Maria, they are using special policies to ensure that the next hurricane season will have less dramatic consequences. In September last year, Puerto Rico was hit by the particularly powerful tropical cyclone Maria. Even four months after the disaster, there were still 225,000 unprocessed insurance claims. Even worse are the 3,700 people who did not die directly as a result of the hurricane, but died due to lack of medication or other shortages.

The idea of blockchain-based automatic payments is not new. The French insurance giant AXA is already using a flight insurance tool that automatically pays for cancelled flights on an Ethereum basis.

The victims of Florence will not yet be able to benefit from the Etherisc solution. The damage is currently predicted to be up to 759,000 houses with a reconstruction cost value of 170.2 billion US dollars.

What is a sidechain?

A blockchain typically consists of a chain of blocks. This chain is usually called the main chain. It links the individual blocks so that a blockchain is created. In addition, there are the so-called sidechains, which run alongside the main chain. In a way, they are branches of the Mainchain. This means that they can exist relatively autonomously next to the mainchain.

This requires tokens to be “transferred” from the mainchain to the sidechain. After all, it should not be possible to spend them twice. Instead, the tokens are “marked” so that they are no longer (temporarily) processed on the main chain. The sidechain is a black box. This means that many independent transactions can take place in this black box without the entire network noticing. Because this only reads the mainchain and therefore does not see what is happening in the background on the sidechain.

An example of a bank
To explain the principle, let us begin with an example from the banking world that we are all familiar with. A bank offers cash and virtual money in the accounts. If the money moves in the form of a transfer, this transfer is recorded by the bank. So it is visible.

However, it is also possible that we will make a withdrawal of 100€. When we use it to buy products, we pass the cash on to other people who in turn use it for their own purchases. This process happens quite often, so many transactions take place in our imaginary cash system. At the end of our experiment, all participants deposit their cash back at the bank.

This is an interesting phenomenon: The amount of cash has not changed, only the distribution. And although many networked transactions have taken place, in the end the bank only sees the closing balances of our individual persons.

Let’s get back to the blockchain: With a sidechain it’s quite similar, because the tokens are transferred to a sidechain and are therefore in a black box.

What are the advantages of sidechains?
A sidechain can define its own rules. For example, a sidechain can use a different Konses algorithm (e.g. proof-of-work) than the mainchain. This allows flexibility within the network and at the same time the possibility to relieve the mainchain. On the sidechain, transactions within the sidechain can be executed largely independently of the mainchain – not all users will notice this. If a normal bitcoin transaction is sent, it is processed by all participants in the network and thus visible to them. This leads to capacity problems with large transaction volumes. Using a sidechain, on the other hand, would relieve the Bitcoin network.

What types of Bitcoin sidechains are there?

  • Custodian – The Supervisor
    The so-called supervisor (custodian) is a central party that reserves the tokens. The bitcoin is sent to this custodian, who in turn holds it in his possession and ensures that it cannot be output on the mainchain. Disadvantage of this approach is that you trust the custodian to monitor the frozen coins.
  • Federation – The sidechain committee
    Instead of placing trust – as with the custodian – in only one hand, a federation can alternatively be formed. For this purpose, access to the frozen tokens is granted via a multiwallet. This means, for example, that there are three keys. At least two of them are needed to open the treasure chest with the tokens. If you give the keys to three persons (e.g.), two out of three persons must agree in order to release the tokens.
  • SPV Sidechain – The automated inspection
    The sidechain variant described in the official side-chain white paper is a so-called SPV side-chain. This requires so-called SPV proofs (simplified payment verification proofs). The technical term means that it is possible to check whether a transaction is contained in a block based on cryptography with only a few required data. If this condition is met, the token transfer is performed.
  • Drivechain
    In a drivechain, the miners are involved in the decision process for the transfer of the tokens. Strictly speaking, these are the custodians (see above) about the transferred tokens – so they can also release them on the main chain again. The drivechain is based on the idea that, given the game theory, Miner’s monitoring of the funds is less dangerous than using a centralized custodian.
  • hybrid models
    Of course, the individual variants can also be combined – nothing else means the hybrid model of a sidechain. For example, RSK Labs has examined a concept that combines the drivechain idea with a federation. Put simply, this allows both the miners and the individual members of the Federation with their keys to decide on the transfer of the tokens.

Lisk – a sidechain network by nature
Lisk is a project that was developed with a special focus on sidechains and above all wants to use the advantages of capacity relief and the possibility of dApp development off the mainchain. In our Lisk-Tutorial we describe the project in more detail.

 

BlackRock changes its opinion about crypto currencies

The largest independent asset manager BlackRock initiates crypto efforts. A team has been put together to check whether the entry into the crypto business is worthwhile for the giant.

The world’s largest asset manager BlackRock, with 6.3 trillion US dollars, checks whether investing in crypto currencies is worthwhile. BlackRock now put together a team of experts to investigate the fundamental structure of crypto currencies, the blockchain, for their own purposes. Furthermore, the experts will see how the competition will contribute to the field of crypto currencies. This examines how the actions of the competition could influence the company’s own business.

A turnaround in the financial sector
The composition of this team shows that the crypto currencies are probably not as insignificant for the New York financial business as Larry Fink claimed last year.

They are “speculative”, “an instrument for money laundering” and the only reason for the flourishing business is anonymity, according to the BlackRock CEO. But that’s not all: Fink also said that crypto currencies are far from providing a perspective for institutional buyers. Furthermore, none of BlackRock’s customers are interested in the digital currencies.

Now BlackRock has even brought the New York financial and investment strategist, Terry Simpson, to help. Let him see if BlackRock should really invest in Bitcoin in the future.

But Fink is not the first in his industry to change his mind
JPMorgan CEO Jamie Dimon also called crypto currencies “fraud” in the past. He would dismiss any banker he caught investing in crypto currency. However, JPMorgan’s chief investigator for Fintech has since been appointed to investigate digital currencies.

Despite many critics, more and more companies in the financial metropolis are opting to invest in crypto currencies. For example, the USD 2.4 trillion asset manager Fidelity Investments, which only last month decided to develop its own crypto currency exchange. It remains to be seen which companies will participate in this movement in the future.

Who is behind Satoshi Nakamoto?

Although the identity of Satoshi Nakamoto is still unclear, there is no doubt about what he created: he is the inventor of the Bitcoin protocol, which he published in a white paper in November 2008 via an encrypted e-mail address.

In 2009 he installed the first Bitcoin client and communicated with the Bitcoin community until the end of 2010. After that, he disappeared from the scene without a trace.

Initially, he worked with an open source team on the project and attached great importance to not disclosing any personal information. Last heard of him in the spring of 2011 when he said: “I will now devote myself to other things.”

Was he Japanese?

You shouldn’t judge a book by its title. Or is it? “Satoshi” means “thinking clearly”, “Naka” could mean “inside or relationship”, “Moto” means “origin or foundation”.

All these things fit the person who created a movement and a sophisticated algorithm. The problem is, however, that every single word can have several meanings.

So there is no certainty that Satoshi Nakamoto is Japanese. For simplicity, Satoshi Nakamoto is hereinafter referred to as with the male sex, although he could also be female or a group of several persons.

Does anyone know who Satoshi Nakamoto was?

New Yorker Joshua Davis believes Satoshi Nakamoto is a cryptography student at Dublin Trinity College called Michael Clear. He came to his conclusion through an analysis of all Nakamoto letters containing more than 80,000 words. In it he searched for linguistic references to Nakamoto’s identity. However, he also suspected the Finnish economic sociologist and former game developer Vili Lehdonvirta. However, both have stated that they are not the inventors of Bitcoin. In a web summit in 2013, Michael Clear even publicly stated that he was not Satoshi Nakamoto.

Adam Penenberg of FastCompany denied the suspicion and said Satoshi Nakamoto was an association of three people: Neal King, Vladimir Oksman, and Charles Bry. He proved that he entered various sentences from the published white paper into Google to check whether these word phrases had already been found somewhere before. It turned out later that one of the three was named in a patent application for updating and distributing cryptic keys. The Bitcoin.org domain that Satoshi Nakamoto used to publish the white paper was registered only three days after that same patent application. According to Penenberg, the domain is said to have been registered in Finland and one of the patent applicants had travelled to the country six months earlier. All three suspects, however, deny being Satoshi Nakamoto.

However, the Bitcoin.org domain was registered on August 18, 2008 by an anonymous Japanese service provider and a Japanese ISP. After that, the domain should only have been transferred to Finland. This somewhat invalidates the Finland theory.

Others claim that the inventor of Bitcoin could also be Martii Malmi. Martii lives in Finland and has been involved in the development of Bitcoin since its birth.

Jed McCaleb is also a suspect. He is known as a lover of Japanese culture and lives in Japan. At the same time, he is founder of the controversial Bitcoin exchange Mt Gox and co-founder of the decentralized payment systems Ripple and Stellar.

There are many more potential Satoshi Nakamotos, including Donal O’Mahony, Michael Peirce, Professor Shinichi Mochizuki and Dorian S. Nakamoto. All deny, however, to be the inventors of an ingenious invention. The Bitcoin community therefore remains uncertain about Satoshi Nakamoto’s identity.

What do they know about Satoshi Nakamoto?

Based on interviews with Satoshi Nakamoto’s companions from the early hours of Bitcoin’s birth, he is said to have carefully thought through the system. According to Jeff Garzik, his encodings did not bear the handwriting of a conventional software engineer.

How rich is he?

According to an analysis by bitcoiner Sergio Lerner, Satoshi Nakamoto is said to have mined many of the first blocks in the Bitcoin network, a total of about one million bitcoins. At the current exchange rate in July 2017, this corresponds to more than two billion US dollars.

What are Soft and Hard Fork?

A fork is the classic development of open source software. Since open source software is of course freely accessible and downloadable by everyone, everyone has the possibility to make their own copy of the software and to modify it for their own purposes. That would have forced the software.

Modifying the software is by no means a malicious intervention, but even an elementary and desirable part of open source projects. Users with programming knowledge can add new functionalities according to their own needs – so different distributions of a software can exist.

What do forks have to do with blockchains?

Starting from a public blockchain like that of the bitcoin, it is ultimately based on open source code that can be modified locally by developers as described above. However, it is essential with blockchain technologies that the network participants agree on certain points. So it would be problematic if some miners in the network use e.g. the SHA-256 hash function and other network participants use a different hash function. After all, you don’t just want to write transactions in your own “household book”, but to carry them out in such a way that they are recognized by as many network participants as possible.

In practice, this is as follows:

  • There is a generally accepted Bitcoin version.
  • Users want new functionalities, e.g. an increase in the block size to solve capacity problems.
  • Any user copies the current Bitcoin software and modifies it with a higher block size.
  • He makes the software available to other users, who can also use it.
  • Now there are two versions of Bitcoin software on the network and users can decide which one to use.

But attention: It is important to differentiate between blockchain forks and forks of software. While forks are used in the latter case to develop new or additional services based on existing ones, forks in the blockchain context rather aim to represent an alternative.

Forks must be classified in particular in terms of their effect on the existing software or on the blockchain network:

Types of Forks

To understand the explanations, you should know what Nodes is all about. Briefly explained, the nodes store the blockchain as network nodes and make it available to the network. In the best case, the current consensus of the blockchain, i.e. the most current transaction history, is stored decentrally on all nodes.

All nodes in the network must be operated with compatible software so that they can communicate on a blockchain. If an amendment proposal is submitted, there are two ways to carry out the fork:

Soft Fork

A Soft Fork is characterized by its backwards compatibility. So there may be nodes in the network that work with the new software. This does not lead to compatibility problems: The nodes with the old software also accept the opinions of the users who have now opted for the new software. On the other hand, users want to establish their standard with the new software and therefore rely on their new method for all blocks.

As soon as the majority in the network is reached, all nodes agree on the new blocks.

Hard fork

This type of fork is not backward compatible – and therefore brings special challenges to guarantee consensus in the network. Existing nodes would have to update their software in order to take the new blocks into account (with the Soft Fork, the existing nodes could simply take the new blocks into account due to their compatibility). The incompatibility of the versions leads to the fact that the network can be split to a certain extent: Users who are in favour of or against acceptance of the changes will then operate on different block chains. This is called a blockchain fork (not comparable to a software fork). It is important to emphasize that a new, stable blockchain is not formed with every hard fork. Ethereum now has five Hard Forks behind it and only one of them has formed a new blockchain with Ethereum Classic.

How is a fork performed?

Let’s have a look at a fork like Bitcoin. The Bitcoin Core Team may be able to suggest changes – but not enforce them alone. In the end, the miners decide which blockchain they follow. This ensures decentralisation, as the network is also left the decision-making authority here. The Core Team can certainly push ahead with further developments – but it has to pitch again and again before the miners and hope for acceptance.

In the past, Ethereum and Ethereum Classic have indeed been a decisive split in the Ethereum Blockchain: After the DAO hack, the community intensively discussed reversing the transfer of the hacked coins by agreeing on a blockchain that does not include this transfer. Of course, option A) hackers may keep their loot with option B) action of the hacker will be reversed incompatible. The procedure therefore requires a hard fork. And as long as 100% of the participants do not agree on a version, the blockchain is split. This happened because there are now two Ethereum blockchains: Ethereum Classic (without hard fork: the hacker remains in possession of the stolen coins) and Ethereum (with hard fork: unwanted transaction was undone).

Miner Activated fork

In this case, the miners in the network decide whether a fork is performed. You signal that you want to perform the fork by appending this information to confirmed blocks. If within the last 1000 blocks a sufficient amount of miners has signalled the fork, the changes are enforced. For example, the new version is valid from 75% approval, from 95% even old blocks that are not marked with the new version are rejected.

User Activated Soft Fork (UASF)

The User Activated Soft Fork (UASF) is a fork that is brought about by a majority decision among the full nodes. It is scheduled to a certain date on which the majority of the full nodes must agree in order for the fork to actually take place.

Miner Activated Soft Fork (MASF)

With a Miner Activated Soft Fork (MASF), the miners decide on the fork with their computing power as voting rights and initiate it. This makes the process more efficient, as the full nodes can accept the changes afterwards. However, MASF involves risks because the network relies on computing power as a benchmark. For example, the computing power can tell you that the soft fork is taking place, but the miners actually continue to work with the old version without the soft fork.

What is a 51% attack and how does it work?

Like any other system, Bitcoin is not perfect. In the context of possible risks, there is often talk of a so-called 51% attack. This tutorial will explain what such an attack is, what it can do and how to prevent it.

Be your own bank is one of the most famous slogans of the Bitcoin community. But such a claim is neglected that a possible decentralisation of the banking system is accompanied by a massive decentralisation of responsibility. Accordingly, decentralization requires enlightened and critical users who are aware of the dangers of possible attacks on the blockchain. One of the most frequently discussed dangers is often a so-called 51% attack.

How does a 51% attack work?

The Bitcoin infrastructure consists of the users (more precisely their wallets), different user interfaces, the miners and the nodes. The nodes are responsible for maintaining the Bitcoin network and managing transaction traffic. Nodes guarantee that all transactions comply with the rules. The task of the Miner is to combine transactions into blocks and append them to the block chain.

In the notorious 51% attack, the following scenario occurs: an attacker succeeds in setting over 50% of the miners. If you take a look at blockchain.info, you can see that three of the large mining pools (Antpool, F2Pool and Btcc Pool) currently have more than 50% of the hashrate – so the concern is not purely hypothetical, but quite real. Other altcoins have had such attacks in the past.

So what could happen if an attacker puts over 50% of the miners? To clarify this, a look at Satoshi Nakamoto’s white paper: in section 11 he looks at the problem of an attacker who wants to feed wrong blocks into the system. Finally, you can calculate how likely it is that an attacker enforces his blockchain.

The figures above show the probability of success, on the left depending on the relative hash rate of the attacker (assuming six confirmations of a transaction) and on the right depending on the number of transactions (assuming a relative hash rate of 26% on the attacker’s side).

It is easy to see that if the attacker’s hashrate is greater than or equal to that of the opponent, the probability of changing things is one. This means that someone with more than 50% of the hashrate on his side would have incredible power. The above formula would then always be decided in his favour. You should also keep in mind: even if the attack is called 51% attack and suggests that you need more than fifty percent of the hashrate for the attack, you can see from the formula of Nakamoto that with less control the probability for the success of an attack is smaller, but success is also not excluded. Accordingly, such an attack may also be successful with significantly less than 51% of the hashrate.

Possibilities of the 51% attack – what an attacker could do

As long as the attacker has control, he could perform double-spending transactions. This means that it could reverse transactions and transfer them elsewhere, messing up the bitcoin ecosystem completely. It could prevent any number of transactions or not assure them of confirmations. The attacker could, for example, specifically block certain payments and thus switch off individual participants. It could prevent any number of miners from mining any valid blocks and instead collect the rewards themselves. The examples show: the potential damage that such an attack can do is immense. Accordingly, the danger of such an attack should be taken very seriously.

What can we do about it?

The advantage of the blockchain is that everything is transparent and can be observed by everyone. On Blockchain.info you can see which mining pools have found which blocks. This is not an antidote, of course, but it can help to see if there are any mining pools that significantly often contribute a block of blockchain.

Apart from that, however, in the case of Bitcoin it is difficult to do something about such an attack as an individual. However, if such an attack occurs, it is advisable for each user to increase the confirmations of a transaction to prevent duplicate transactions. If an attacker really had 50% or more of the hashrate, this would not change the fact that the blockchain version of the attacker would always prevail, but it would take important time. Time that is valuable because it is incredibly expensive at Bitcoin to maintain 51% of the hashrate.

From Gavin Andersen’s point of view, who coined the bon mot “That would be bad” with a view to a 51% attack, it is relatively easy to defend against such an attack from the developer’s point of view. One idea would be that the attacker would have to have not only a lot of hashrates but also a lot of bitcoins from the time before the attack (see here). Overall, this would not only make the 51% attack quite expensive, but also ensure that the attacker bleeds out quickly.

In summary, a 51% attack on bitcoin is a serious matter, but one that can be uncovered. Especially in the field of prevention, Bitcoin users have an important task: it is up to them to keep an eye on the entire network at all times.