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Anyone interested in entering the world of Bitcoin, Blockchain technology and the rest of the cryptocurrencies, must first get to know the different concepts or elements involved in its operation, so you can have a clear idea of how this is handled complex ecosystem.
Terms like hash, Proof of Work and Proof of Stake, are some of the most common when it comes to understanding any cryptocurrency and its respective blockchain platform. Particularly because it allows the understanding of the consensus mechanisms used for the verification of transactions between users and the way in which these will be added to each block belonging to the chain.
Despite the fact that the Work Test is the best known, as the system implemented in Bitcoin mining, the Participation Test and more recently the Capacity Test, which will be discussed in this article, has also been developed in other projects. .
## The hashing as a preamble
In the Capacity Test as well as in the Work Test, the use of the hash function is required. This hash function, which is unidirectional, refers to a mathematical operation where information is entered in any size, an operation is executed and then the same information is returned as output data in another size, usually in the form of an alphanumeric string.
For example, Bitcoin uses the SHA-256 hash function, where the incoming data is the last performed transaction that has not yet been confirmed, together with the data from the previous block and the output data end up being a completely different result. The disadvantage in this case is that it is easy to enter new information and calculate the hash, but the degree of difficulty lies in taking the hash and defining the original information.
## Proof of Work or Proof of Work
As mentioned in other articles, the Work Test is a computer algorithm used by some cryptocurrencies such as Bitcoin, Ethereum, Litecoin, Zcash, among others, in which they decentrally agree which of the blocks will be added to the chain once that is mined.
In each platform, the miners carry out the resolution of variable and complex mathematical problems where, when giving the corresponding resolution, they obtain a reward in chain of blocks, each highlighting that for this activity it is necessary an optimal computing power and sufficient electrical energy to execute all these operations.
In a simplified example of the Work Test, the miners collect transactions in a block, then quickly adjust by small variations, the heading or "nonce", so that they can obtain a result equal to the objective hash and thus mine the block successfully.
## ¿What is Proof of Capacity or Capacity Test?
Unlike Proof of Work where it takes a great computational power to perform calculations or Proof of Stake where a certain amount of units must be available in cryptocurrencies, the Proof of Capacity Test is an algorithm used as a consensus mechanism that allows store in the free space of the hard disk, the computations of the possible solutions before carrying out the mining.
The advantage of this mechanism is that if the solution is contained in the disk, the mining process will be faster and you can claim the corresponding reward, so that the more capacity the hard disk has and the more solutions it has stored, the easier it will be to mine the block.
This mechanism was born as an alternative to solve the problem of large energy consumption and high expenses in computer equipment, as well as to avoid the problem of maintaining the permanent possession of a cryptocurrency.
## ¿How does the Capacity Test work?
The Capacity Test is done in two parts, a hard disk layout and the mining process as such.
In the trace or Plooting a list of all the possible values of nonces is produced, which will depend on the size of the hard disk, this creation can take a long time depending on the number of unique files that are created. Each of the nonces contains up to 8192 hashes organized in pairs called "scoops" to which a number from 0 to 4095 is assigned.
The hash used for the trace is known as "shabal" and is different from the SHA-256 hash that the miners implement in Bitcoin, especially in terms of the speed of calculation and the difficulty of it.
After the trace is made, the mining part is executed. At this stage the miners calculate a scoop number with the first nonce and the result would be a deadline called the deadline. This process will be repeated, until all the terms of the nonces stored on the hard disk are known.
Subsequently once all the deadlines are known, the miner must only select the minimum deadline, which covers the seconds that must pass from the last mined block to the next mined one, so if no one has carried out the process in this In time, the miner takes the opportunity to do so and claim the reward.
## Advantages and disadvantages of this mechanism
Among the most important advantages of this type of mechanism, is the fact that it can be used in any type of hard disk, even those that are incorporated into mobile devices under the Android operating system.
Another advantage is the efficiency it can offer, being considered up to 30 times more efficient than any type of ASIC mining equipment. In such a way that the acquisition of special hardware, its maintenance or updating would not be necessary.
On the other hand, this concept implies a much more decentralized mining activity, for the simple reason that each person has their own hard drive in whatever device they maintain. In addition, there is the practical element that at any time you can delete the information and reuse the disk normally for any other purpose.
Regarding the disadvantages, one finds the fact that it is not very popular today, nor has it been tested to its full capacity in the real world, currently it is only used by a single cryptocurrency called Burstcoin.
Another detrimental aspect is that just as malware has been developed to infect computers and mine cryptocurrencies, it is also possible that the Capacity Test may be compromised by some type of malicious program that affects the hard drive.
## Conclusions
This consensus mechanism can be an interesting alternative to solve the problems that currently exist with those that are already in operation. The fact of being more decentralized, not needing large amounts of energy, or having to purchase expensive specialized equipment can be a point in favor of its adoption.
However, as its applications have been few, the full impact it can have on the ecosystem of cryptocurrencies and blockchain technology can not be determined. Therefore, we must wait for a better development of the concept in the future.