As a distributed system scales it has one of two choices: scale horizontally (more nodes) or vertically (more powerful nodes). In the spirit of decentralization, the choice here is for them to scale horizontally
The average person wonât be able to acquire specialized hardware, so the result is centralization around either wealthier individuals or pooled resources.
Sharding is a form of horizontally partitioning a database (and thus modularize it to make it scalable)
So for Ethereum, sharding looks like having a dynamic subset of nodes that process block by block
The main follow up here being: how do we still retain the security benefits of a large decentralized system while still lifting the requirement that every node needs to verify and execute every transaction? The implication being that with shards, an attacker could make a focused effort to attack a single shard (and act maliciously)
Ethereumâs Solution: randomly shuffle the validators responsible for verifying/executing transaction on a given shard block. Every shard block gets assigned a randomly chosen âcommitteeâ of validators such that an attacker would need control over 1/3 of all of the validators to gain majority within a single shard (probabilistically)
