Not long ago there was a real gold rush around cryptocurrency mining - thousands of people started digging digital rock to get the precious digital gold, while its rate was beating all records and surpassing all expectations. It all started from simple mining on users devices - laptops, personal computers, tablets, etc. - and turned into a complicated industry with a developed infrastructure. Mining pools appeared, specialized equipment ( ASIC-miners ) was produced, huge mining farms were set up, where mining was conducted on an industrial scale. Mining even partially switched to the cloud - services appeared that offered cloud cryptocurrency mining without any investments, except for financial ones. Although mining has not changed the structure of the world economy, it is nevertheless not an ordinary phenomenon. The fact that currently cryptocurrency mining consumes more electricity than many countries is a case in point.

Today we will talk about what mining complexity, its function, how it changes, what it depends on and how can it set the tone for the entire cryptocurrency mining industry.

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1. Brief review of mining

Mining actually means making computational operations to decode a certain algorithm and find its hash. Every mineable cryptocurrency is based on a particular hashing algorithm. When the algorithm is successfully decoded, a new block is added into blockchain, a new coin is issued and miners get their rewards. Many popular digital currencies can be issued only through mining, these are Bitcoin and its forks, Ethereum, Monero, Litecoin, Dash, Zcash, etc. Some, however, are pre-mined and do not provide mining opportunities, like Ripple, NEO, NEM, EOS, Tether, etc.

Depending on hash features, different equipment can be used to mine different digital currencies. Initially all mineable coins, including BTC, were mined on users devices (PCs or laptops) using CPU. Today it is not that common and there are a few popular coins that still provide such type of mining. Soon CPUs became not enough to profitably mine digital coins and miners started using graphic cards to cope with more resource-intensive calculations and growing complexity.

Later the specialized equipment appeared on the market - ASIC-miners that are used today to mine Bitcoin, as well as other coins, such as Litecoin, Ethereum, Dogecoin, Zcash, Bitcoin Cash, Litecoin, etc. ASIC is a specialized microchip that performs calculations much faster than graphic cards. Although ASIC today is mostly associated with mining, the technology itself was developed in early 1980s to advance graphic performance of PCs. Besides, miners create pools where they combine their processing power to make mining more efficient for the whole group. The reward for the created block is then distributed depending on the processing power provided by each pool member.

There is also another mining solution - cloud mining. Graphic cards and ASIC-miners are rather expensive, more and more of them are required to mine profitably. The equipment needs space to be placed, has to be connected to the power grid, cooled, cleaned, repaired, set up, monitored, etc. Cloud mining implies leasing of computing power from companies that manage large mining farms and data centers. In addition, cryptocurrency is mined in other sometimes even illegal ways. For example, your computer can be infected with a hidden virus-miner that uses its resources to mine a particular coin.

2. Complexity: how it changes and what it depends on

Complexity indicates how difficult it is to find hash. The specified hash parameters determine how difficult calculations should be to find it. The more users are there in the network and the more cryptocurrency is mined - the higher complexity is. Bitcoin complexity is reviewed every 2016 blocks (about 2 weeks) and depends on how much time was spent to mine previous 2016 blocks.

What is the function of complexity? Bitcoin is designed to add every new block in 10 minutes on average. This can differ from one cryptocurrency to another (2.5 minutes for Litecoin and up to 20 seconds for Ethereum). The amount of processing power in the network can drastically change over time - when Satoshi Nakamoto mined the first BTC, there was only one device in the network, probably a laptop or a PC. Today we have huge industrial farms with thousands of special mining devices.

To ensure the stability of the generation of new blocks, cryptocurrency software automatically makes it more or less difficult for miners to find hash. So if there are more miners and the computing power of the network increases, it is more difficult to find hash. If the power decreases - it becomes easier to make all necessary calculations. This is the way the system remains sustainable - no matter how much processing power is their in the network it will still take around 10 minutes to generate new Bitcoin block. In early 2010, Bitcoin complexity was just a little bit above 1, while in 2013 it was already 3 million. Today it has already exceeded 7 trillion.

Source: BitcoinEnergyConsumption.com

So, every 2016 blocks (about every two weeks), Bitcoin corrects its complexity, so that each block is generated in approximately 10 minutes, regardless of the number of miners in the system. Other mineable cryptocurrencies has the same role for complexity and it is implemented in a similar way.

3. What will happen to the mining in the future

Mining is no longer the same as it used to be - says… everyone. While some digital currencies can still be mined using PCs, it is rather difficult to join the “extraction” of most of the leading coins. To start mining Bitcoin today you should have… started mining Bitcoin a few years ago. The same thing is happening to other digital currencies, and ASIC-miners are to blame in fact. They are able to make calculations way faster and more efficient and wherever they enter the mining market, the total complexity increases and CPU/GPU-mining retires. However, some still manage to make money out of mining. There are still those coins that are not mined using ASIC-miners, which means one can still mine them on average laptops or PCs.

Anyway, one thing is clear - today, mining is no longer stands for easy money, and the market is being taken over by large, "professional" miners, who mine digital coins on an industrial scale. Industrial mining is associated with a whole range of logistics, legal and resource issues. Until recently, most of Bitcoin miners were located in China, but last year the government banned ICOs, cryptocurrency trade and mining. Another thing is energy consumption. Calculations require a lot of electricity, so the miners are looking for countries with lower power prices.

Source: BitcoinEnergyConsumption.com

Another problem is obsolescence of equipment. Many industrial miners have found out, that the hardware they used to mine BTC 2017 cannot ensure the same profit in 2018.

So, mining becomes less profitable and new members have no chance to join the market easily. This lead to the fact that mining of top coins becomes way less popular. Not mineable coins, as well as those who still provide available mining can take advantage of that. For example, in 2017 there was a boom for mining browser extensions (like Coinhive). Of course, browser-mining of Bitcoin or Ethereum sounds rather weird, but there is another relatively popular coin - Monero - that still provides such an opportunity.

4. Conclusion

So, complexity is one of the key categories that form a technical structure of mineable cryptocurrencies. Written in the protocol, it helps blockchain to remain sustainable in terms of the time necessary for the generation of new blocks. Complexity directly depends on the number of miners in the network and, accordingly, on the total processing power. Most of the leading cryptocurrencies have already became much more difficult to mine and this is obviously an ongoing process. There are more users, more special equipment and more professional industrial-scale miners which make mining unavailable for average users.