Deep Dive into Validity Proofs and Layer 2

Scaling Ethereum has served to be a difficult yet important task. With Ethereum’s growing popularity, the demand for transactions to be included in blocks has skyrocketed along with the transaction fees. With Ethereum’s layer 1 processing around 15 transactions per second at full capacity, it seems necessary to implement mechanisms that increase throughput. In order to reduce the load put on Ethereum nodes, there have been many layer 2 (L2) solutions arising which aim to limit the amount of computation or storage needed on the mainnet, each with their own benefits and drawbacks. An overview of many of these layer 2 solutions can be found here, but this piece focuses on L2s utilizing zero-knowledge proofs.

It is hard to ignore the prevalence of zero knowledge proofs in emerging scaling proposals. These proofs are constructed in a way such that the only fact someone reading the proof learns is the validity of the statement. For instance, if Alice wanted to prove to Bob that she knew how to count the number of hairs on Bob’s head, Alice could explain to Bob how she does it and Bob could try it out himself and be convinced. However, if Alice didn’t want to reveal the secret to her special skill, she could tell Bob the number of hairs on his head. Bob would not actually know the validity of this since Alice hasn’t told him her methods, but what Bob could do is have Alice turn around and remove a certain number of hairs from his head. Alice would then guess again, and Bob would check if her previous answer corresponds to the number of hairs he took out. It is then up to Bob to repeat this process as many times as he wants until he is satisfied with his knowledge of Alice’s talent, but he will know nothing other than that Alice can count hairs.