Arweave

The Arweave protocol was designed as a solution to the problem of online data storing. Arweave allows for permanent and scalable on-chain data storing, becoming a foundation for the permaweb. It would mean an interconnected, decentralized web that never forgets any data. No more "404 page not found" messages.

Arweave protocol is a structure called a blockweave. Unlike a blockchain which links each new block with a previous one, a blockweave makes two such links. The previous block, like in traditional blockchains, and a "recall block" are linked to a newly created block. As such, Arweave does not create a linear, single-linked chain, but rather a bit more complex structure. The recall block is chosen by taking into account the hash and height of the previous block.

At first, Arweave used a modified version of the Proof-of-Work consensus mechanism called Proof-of-Access. Hybrid PoA consensus requires the complete data of the recall block to hash for input for PoW. This approach means that miners need to have access to random blocks on the blockweave. Less-replicated blocks also become more valuable to miners. If fewer miners have access to a specific block, this means they have a higher chance when competing with each other for rewards.

In 2021 the protocol was updated to utilize Succinct Random Proof of Access (SPoRA). The new mechanism has greatly increased the speed at which new blocks are being produced. It has also caused a decrease in energy consumption required to maintain the network. This is because the SPoRA system has a lower energy demand than PoW.

AR is Arweaves native token, and it is used for two primary functions. The first function is rewarding miners for block creation. It is also used as payment for storing data within the system. A user that wants to write their transaction into a block, must pay a fee in AR tokens. Unlike in traditional blockchains, only a part of the fee is sent directly to the block's miner. A large portion of the fee is put into a storage pool, from which rewards are later distributed to the wallets of various miners.