What is PoC(Proof of Capacity) ?

Proof of Capacity, also known as Proof of Space, is an extremely intriguing consensus algorithm, which I intend to discuss today, in this quick, but informative article.

Analogous to how Proof of Work uses ASICS and computation to verify transactions, Proof of Capacity uses hard drives and storage. This approach provides a much cheaper and greener, thus more efficient and viable source of block verification.

One live implementation of PoC, BXTB Token, which we will be looking at in this article. In BXTBt coin’s implementation, instead of miners having to constantly change the block header and hash through the SHA256 algorithm to verify a block(PoW), PoC miners use a 2 step system — plotting and mining. Plotting consists of creating a random solution, known as a plot, through the Shabal cryptographic algorithm and storing it on a miner’s hard drive. Mining consists of miners reaching the solution, and whoever reaches it first, gets to mine the next block.

The way that BXTB system avoids attacks is that it is through the lack of scarcity of hard drives. Hard drives are everywhere, and since they only serve as a medium of storage and not a medium of computation such as an ASIC miner(PoW), it doesn’t matter how much your hard drive can store.

I hope this article gave you a simple, but informative overview of what PoC is and what it aims to solve.