I choose to write about "Proof of capacity (PoC]". For better understanding of PoC, a brief mention of proof of work (PoW) is mandatory. Before going on to PoW , let's recall what we understood by the definition of consernsus algorithm as explained by professor
@alphafx .
Consensus algorithm is a system of well implemented codes on the blockchain that serve the purposes like verification of transactions before recording ( we know none of the transaction on blockchain is recorded before being verified) , storage of transactions in small interconnected units called blocks, and after successful completion aid in rewarding miners and therefore maintain integrity of the blockchain. So keeping this thing in mind, let's move on to PoW.
Proof of work (PpW/ is a system of mining that is required for validation of transaction before being accepted by blockchain . Let's take example of Bitcoin, suppose a transaction is being done. it has to be stored on blockchain in the form of blocks on computers known as nodes. After storing copy of block, it is immediately transferred to other nodes for validation. To be accepted by network, a new block must contain proof of work which requires miners to find a number called Nonce (number only used once). Nonce is a mathematicsal computation which a miner need to discover before solving a block in a blockchain. This process is carried out by miners with the help of computers or similar devices with high computational power. Remember, PoW is a game of computational power. More the computational power, more rapidly miners will be able to find Nonce and validate the transaction and therefore get rewarded.
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Proof of capacity is a consensus algorithm in which storage capacity of the devices, put in use for validation of the transactions (mining) , is used for storage of solutions of the hashing problems ( Nonce ) . PoC is sometimes also known as Proof of Space. For better understanding, i would like to highlight points of differamce between PoW and PoC.
PoC makes use of storage capacity of devices on which it is carried out , whereas, PoW makes use of computational power of devices.
For PoC more the storage space of devices put in use, more is success and in PoW more the computational power, more is success.
In PoC, solutions of hashing problems are stored beforehand and they are only matched with the target hash at the time of validation. In case of PoW, there are no preformed Nonce but they are generated at the time of validation of transaction.
PoC is an energy efficient alternative to PoW . We know the energy consumption in PoW has always been in limelight because for higher computational power, miners make use of devices that consume huge amount of energy and that issue has been well addressed by PoC.
Blockchains that run on PoC are Setorj, Burst, Chia, and SpaceMint where as those that run on PoW are BTC , Bitcoin Cash , ETH, Litecoin, DASH, Monero etc.
Working of Proof or Capacity (PoC).
Proof of capacity is a multi step process. Different steps involved in PoC are sequentially listed below. These steps have been derrived by me, while i was trying to understand working of PoC. You may not find such list on the web. So it is not something standard as it is not bookish.
However, process will be same on the web too.
Create a list of Nonce values.
Numbering of hashes.
Pairing of hashes.
Calculating of scoop number.
Calculation of deadline time stamp.
Selection of Nonce with minimum timeline for matching.
Race for rewards.
Description of working of PoC.
Keeping above mentioned steps in view, let's try to understand working of PoC. Suppose i am a miner, I'll start by plotting a hard drive and using my mining account, I'll create list of all possible Nonce values to be stored on hard drive. Nonce is a collection of hashes and remember each Nonce contains 8192 hashes. So we are done with step one.
Next I'll be doing numbering of hashes within Nonces, starting from 0 to 8191 as there are 8192 hashes within each Monce. Than i will pair the numbered hashes together to form scoops. A scoop is a group of 2 adjacent hashes in a pair. For example , scoop 0 is name given to hash 0 and 1 , scoop 1 represents hash 1 and 2 , scoop 2 is hash 2 and 3 etc. So we have 4096 scoops within a Nonce.
Next I'll begin actual mixing process where I'll generate scoop mumber. For example, scoop number 10 was generated. Next, I'll be looking for scoop 10 of all the Nonces that are there on my hard drive. The purpose is to find the scoop 10 with minimum deadline value ( time between forging of blocks) . Suppose i find scoop 10 of any Nonce with deadline time of 30 secs. I'll have to wait for 30 secs and look how quickly other miners are able to forge. If no miner was able to forge block within 30 secs, than I'll do it and claim minimg rewards.
Pros and Cons of PoC
We know that nothing is absolute in universe. PoC has been able to handle certain things better but is not a perfect protocol. It has certain weaker points.
Pros of Proof of Capacity.
As mentioned above, it has emerged as an energy efficient system. it is said that , PoC is 30 times more energy efficient than ASIC system put in use for Bitcoin mining.
No complex hardware system is required for PoC. A simple hard drive that we use on day to day basis can be put in use.
it is cost effective for several reasons. When compared with ASIC system used for BTC mining, PoC storage system has market price much lesser. Secondly, the regular maintainance charges and system upgradation is not an issue with PoC.
At any point of time, you can utilize the device for any other purpose in routine life by erasing mining data.
No environmental issues like carbon emission, heat generation and noise pollution are posed by PoC system where as the above mentioned issues have been in limelight from time to time in context to BTC mining.
Cons of Proof of Capacity (PoC).
Conclusion.
Proof of capacity is a comsensus algorithm of blockchain like proof of stake (PoS) , Proof of Work (PoW) etc. It has emerged as an alternative to other consensus algorithms as for energy consumption is concerned. It doesn't make use of heavy computational power like PoW or heavy stake share lile PoS, instead it relies on use of storage capacity of hardware devices for solving hashing problems.
Thanks
Hi, @drqamu you have explained very well but you have made a mistake in the title.
Incorrect: comsensus
Correct: consensus
this mistake is repeated many times in this homework post maybe because of auto-correct it happens with me too.
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Well done, see you next time
Thanks for participating
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@alphafx
Dear professor, i am not satisfied with your rating system. It would have been better to have suggested areas of improvement than going on rating as per nothing. Let me tell you what i mean, you rated presentation as 1/2 , it means, i am only 50% correct in presentation as per you but as per my own strategy i did my best. So i don't know, where to improve. Your review should have highlighted and examplified the areas of improvement, so that i would put more efforts on those areas and perform better next time. As such your review is no ways beneficial for me. Pardon me, if it seems egodystonic to you.
Regards
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I am sorry, I replied you almost immediately but my comment must not have loaded before moving to the next tab or I lost connection. Your score for presentation waa updated, the dark mode I use did not let me see the borderlines for proper demarcation and spacing at first view.
Projects using this algorithm, little was offered on it, and it was hidden under a different sub-topic, comparison, I was looking out for it.
Originality is just my way of rewarding students for creativity, designing their cover photos, and illustrative photos by themselves.
I hope I cleared you?
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