Rollups

 

Instructor:          Andreas Park
 

 


Rotman – MBA

First: some data

Ethereum is "full"

Source: Etherscan w re-scaling

Basic idea of a Rollup

rollup
API

rollup
layer

by a sequencer

The process explained

users lock up funds in a special smart contract

a

b

 

e

f

g

perform operations or transact

sequencer creates a digest of bundled/rolled-up transactions

sequencer posts digest to mainnet

What's this?

Optimistic roll-up:

  • sequencer posts transactions/data and it's assumed correct unless challenged
  • challenge period = 1 week
  • there are challenge rewards
  • correctness/faultiness is provable
  • (the concept is called a fraud proof)

ZK-Rollups

  • sequencer creates a proof that transactions are correct
  • easy to check, hard to fake
  • (the concept is called a zero knowledge proof)

Pros

  • easy to post/create

Cons

  • delay in checks/finality
  • requires collateral

Pros

  • easy and fast to check

Cons

  • proofs are hard to generate
  • only works for simple transactions
  • "account abstraction"
    • ​= smart contract wallets
    • no gas payments in crypto ("sponsored")
    • great simplification

Some things you can do with a rollup

  • high throughput applications
    • ​trading platforms
    • payments systems
    • reward systems
  • AML/KYC checks
    • => determine who gets to play on your rollup
    • be regulatory compliant
  • create "local" tokens
  • ​non-finance applications
  • private transactions using zero-knowledge proofs
  • digital ID applications

a

b

 

e

f

g

users lock up funds in a special smart contract

sequencer creates a digest of bundled/rolled-up transactions

perform operations or transact

sequencer posts digest to mainnet

How is a rollup different from a crypto-trading platform?

  • crypto platform: ownership transferred to platform

crypto platform: transactions enabled on a seperate system with no proftable relation to blockchain

rollup: ownership transferred to smart contract; retain control within rules of smart contract

rollups:

  • transactions follow blockchain rules (digitally signed)  
  • blockchain mainnet checks vality
  • sequencer subject to punishment for violations
  • sequencer has no direct control over funds

More data

What's happening? Is the L2 party already over?

EIP-4844: enabling of data blobs

basic idea:

  • reserved space in blocks for "data blobs"
  • collections of transactions from rollups
  • much cheaper gas fees for sequencers

Rollups

By Andreas Park

Rollups

This deck introduces rollups

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