Questions tagged [rollups]

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Why a zk-rollup should provide data availability given it can use zkp to prove correctness?

The whole idea behind zkp is to prove correctness of the result of a computation without actually disclosing the inputs that you might want to keep secret. So why in the context of zk-rollups it is so ...
Davide C's user avatar
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How do people solve NFT cross-chain when developing on your own rollup?

This is a question about developing a game using its own side-chain. In this case, the NFTs would be minted on the side chain. Now the players can trade NFTs with each other but some of them might ...
Justin Zhang's user avatar
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Comparison of NEAR and Celestia Data Aavailability Approaches? [closed]

Recently NEAR has come up with a Data Availiabity approach which they claim to be far more superior to a lot of existing techniques. Celestia DA leverages 2D Erasure Coding based Data Availability ...
Gokul Alex's user avatar
3 votes
1 answer
35 views

ZK rollups: How to check whether specific transaction is included in batch?

ZK rollups don’t store transaction on L1. They just need the Zk proof the check correctness of state transition and additionally state diff so users would be able to reconstruct the rollup state in ...
Felix's user avatar
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2 votes
1 answer
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ZK rollups: How is state diff data in batches checked for correctness?

Situation: ZK rollups don’t need to publish any transaction data on L1 to ensure correct state transition because the zk proof takes care of correct state transition without knowing (i.e. zk) anything ...
Felix's user avatar
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1 answer
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Are rollups run by a single sequencer centralized from a censorship point of view?

In other words, can sequencers censor txs on rollups such as Arbitrum or Optimism?
Paul Razvan Berg's user avatar
1 vote
1 answer
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In optimistic roll-ups, can a validator post a valid block that builds on an old-but-invalid block which was not challenged?

In optimistic roll-ups, blocks (aggregated transactions) are published on the Ethereum main net. The main net functions as a security layer for the roll-up in the sense that it leverages the security ...
Kianoush Arshi's user avatar
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Optimistic rollups and simple transactions

My understanding is that in an optimistic rollup, all data from users authorizing a transaction is stored on L1. The computation itself corresponding to that transaction is executed on L2. For simple ...
user1936752's user avatar
2 votes
1 answer
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Why does rollup data in Ethereum have to be on chain?

In this blog, it is said Rollups move computation (and state storage) off-chain, but keep some data per transaction on-chain. The fact that data is on-chain is key (note: putting data "on IPFS&...
user1936752's user avatar
1 vote
0 answers
59 views

What happens with Chainlink price feed when L2 sequencer is down?

What exactly happens with chainlink price feeds when an L2 sequencer is down? I know that during this moment transactions can be submitted only through L1 rollup contract and that some users can be ...
urataps's user avatar
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2 votes
2 answers
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Rollup Operators Colluding and Withholding Data?

For Rollups like Optimism and Arbitrum, what happens if the sequencer colludes with a proposer so: The sequencer withholds data The proposer publishes an invalid state update (so he can drain the L1 ...
Rodrigo Herrera Itie's user avatar
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What exactly is Fuel blockchain?

They describe themselves as execution layer for the modular blockchain, but what exactly does this mean? If they are the execution layer, where are the other functionality/layer? Consensus layer, data ...
Finlay Weber's user avatar
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1 answer
79 views

Are there any Ethereum L2 projects that built based on the Parity Substrate framework?

Substrate is a powerful framework that makes it easy to build a blockchain. I am more familiar with the substrate development than the Layer2. and am curious about why there are no Ethereum Layer2 ...
boundless-forest's user avatar
1 vote
0 answers
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why does optimism need to derivation from L1 but zk-rollup scheme like polygon zkevm not?

recently I am reading the optimism docs and the spec named derivation confuse me. I haven't found it in any docs of zk-rollup projects like zksync, Polygon, or zkevm.
meta's user avatar
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Who pays for the L1 gas costs of ZK-rollups?

I have deployed the same smart contract on both the Goerli Testnet and the Polygon zkEVM Testnet. When I execute the same interaction, it costs the same amount of gas on both networks (as expected), ...
Abel's user avatar
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1 answer
115 views

What does it mean by "rollups sends transactions on mainnet"?

While trying to understand what rollups are, I read rollups sends transactions to mainnet in a batch. I don't understand why and practically what does it do. To better understand it, I came up with a ...
Stav Alfi's user avatar
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2 votes
0 answers
16 views

Difference between zk-rollups and nocust-zkp

What is the fundamental difference between ZK-Rollup and Nocust-ZKP? Does the data availability problem still persist in Nocust-ZKP? After going through zk-sync, I felt it might be fundamentally ...
Subhra Mazumdar's user avatar
1 vote
0 answers
50 views

what data of zk rollup blockchain are sent to l1?

I am not clear about how data flow from l2 to l1 in zk rollups. does someone knows what data of l2 are sended to l1?
aakash4dev's user avatar
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1 answer
102 views

smart contract rollup vs sovereign rollups?

I read here about smart contract and sovereign rollups: https://celestia.org/learn/sovereign-rollups/an-introduction/. I am curious to know what are the pros, cons and differences between both types ...
aakash4dev's user avatar
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8 views

which L1 blockchains are truly modular blockchains?

I want to know which blockchains are modular blockchains. I know about cosmos and Celestia, and I guess they are L1 modular blockchains, also I know that rollups are L2/Ln modular blockchains. But ...
aakash4dev's user avatar
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how to use snarkjs for NEAR protocol. how to make ZK prover/verify function in NEAR protocol with typescript?

i wanna make ZK-rollup whose L1 layer will be NEAR protocol. what's the way to make Verifier function in Typescript of NEAR protocol ? This function is not working:- import { NearBindgen, view } from &...
aakash4dev's user avatar
1 vote
1 answer
28 views

calldata usage, difference between the method calling function with calldata

I recently studied optimism, and found that appendSequencerBatch() of CanonicalTransactionChain contract called with calldata. I assumed that this function was called using 0x(functionSelector)+(data.....
gun bos's user avatar
  • 25
2 votes
0 answers
37 views

What is "Data availability problem" in Plasma?

What differentiates Rollup from Plasma is that it solves Plasma’s huge problem — data availability Can someone please describe the "data availability" problem in Plasma? Ok, in Plasma the ...
YodaDefi's user avatar
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Has the state channel died?

State channels and rollups are both layer-2 scaling solutions for blockchain networks, with state channels being around for longer. State channels allow users to conduct off-chain transactions while ...
user77340's user avatar
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1 vote
0 answers
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Rollups vs Plasma

This question is related to my another question - Plasma - "If owner does not care about their asset, then an "invalid" outcome may result"? Here https://vitalik.ca/general/2021/01/...
YodaDefi's user avatar
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1 answer
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Plasma - "If owner does not care about their asset, then an "invalid" outcome may result"?

From Vitalik's article "An Incomplete Guide to Rollups" (https://vitalik.ca/general/2021/01/05/rollup.html): Additionally, Plasma and channels share a key weakness in common: the game ...
YodaDefi's user avatar
0 votes
1 answer
175 views

circom error in zk-rollup circuit: circom error: circuit too big for this power of tau ceremony. 6600*2 > 2**12

while making zk rollup circuit of merkle, i got this error. code for .circom: pragma circom 2.0.3; include "modules/mimicsponge.circom"; // ref: https://github.com/4undRaiser/...
aakash4dev's user avatar
0 votes
1 answer
36 views

bn.inherits is not a function in snarkjs

i am going through this https://github.com/iden3/snarkjs to make zk-rollup via .circom and snarkJS, when i tried to run index.html code it didn't work as per it should. and give error bn.inherits is ...
aakash4dev's user avatar
1 vote
0 answers
23 views

how polygon zk hermez send data from l2 rollup chain to circom circuits?

I'm trying to make rollup, wanna know how rollup works, and specially about one of the good rollup chain polygon hermez.
aakash4dev's user avatar
1 vote
0 answers
133 views

what is the best way to compress/decompress data within a solidity smart contract?

I'm working on a l2 optimistic rollup academic project (thesis), where the sequencer would submit the compressed txs as calldata. At a dispute (aka a different post-state), a verifier would challenge ...
seraleo's user avatar
  • 11
2 votes
1 answer
51 views

Why optimistic rollup chains can take a week, while ZK don't?

Optimistic and ZK rollups, both submit data to Ethereum or similar chain, but why do optimistic rollups take longer time then zk rollups? What's the core difference that causes this time difference?
aakash4dev's user avatar
1 vote
1 answer
23 views

In rollups, does only layer 1<->2 cross chain transfer data is submitted to main chains, or all transactions data of rollup chain?

rollup chains batch the transactions data of its blocks/transactions, and submit it to mainnet(layer 2 e.g. ethereum ). But i doubt if rollup chain submit all data of all transactions in batch form, ...
aakash4dev's user avatar
1 vote
0 answers
47 views

how to make rollup sequencer decentralized?

I know the logic to make a centralised sequencer for a blockchain rollup ( layer 2 solution ) , but i have no idea on how to make the sequencer decetralised. so that no one central authority will get ...
aakash4dev's user avatar
3 votes
2 answers
438 views

How layer 2 blockchain communicate with layer 1 blockchain? where does that communication part is hosted?

I understood what is layer 2 via various blogs, videos and this page: https://ethereum.org/en/layer-2/ But I wanna know: how the layer 2 blockchains communicate with layer 1 blockchains? I guess a ...
aakash4dev's user avatar
1 vote
0 answers
38 views

Arbitrum: Mapping L2 blocks to L1 batches using RPCs

I'm looking for a way to programmatically map L2 blocks to their corresponding rollup batches in L1 using RPCs. Is there a way to do this, and if so, what would be the best approach? Any help or ...
Lucas Pecina's user avatar
0 votes
2 answers
289 views

How do layer-2 bridges and protocols earn revenue?

Everytime I've used a bridge like Polygon and Aztec, all they charge are gas fee transactions to make the transfers and lock-up conversions between layer 1 and layer 2. Bridges therefore are nothing ...
user610620's user avatar
  • 1,498
1 vote
1 answer
37 views

How can privacy roll-ups like Aztec make my transfer cheaper?

Aztec or zk.money, a Layer-2 roll-up, claims to make transactions not only private but also cheaper. If I send 1 eth on L1 mainnet, all I pay is one gas txn to send it. If I instead use Aztec's ...
user610620's user avatar
  • 1,498
2 votes
2 answers
156 views

Will Layer-2s and zk roll-ups become redundant once Eth 2.0 sharding and scaling arrives?

Millions of VC funding dollars are going into Layer-2 solutions like Optimism, Arbitrum and Polygon to allow users to side-step mainnet Layer-1 and process transactions at a thousandth of the cost and ...
user610620's user avatar
  • 1,498
0 votes
0 answers
278 views

Why does Chainlink VRFv2 not support L2 rollup chain like arbitrum or optimism?

All the popular L2 rollup chains are not listed in the supported networks per doc: https://docs.chain.link/vrf/v2/direct-funding/supported-networks/. Meanwhile, Aribitrum and Optimism do have ...
yl35's user avatar
  • 11
4 votes
2 answers
370 views

How verify transaction data in zkrollups?

The stateroot transition is verified by witness (pre- and post- state root) and proof, but validators also should verify the transaction data which is proposed by operators. How can verify the ...
amanec's user avatar
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1 vote
2 answers
589 views

Can I roll multiple transactions into one?

I wonder whether it is possible to roll multiple transactions into one transaction and post it on the chain, similar behavior to L2 chains. I will have a smart contract where there might be a high ...
Ahmet Yazıcı's user avatar
4 votes
2 answers
55 views

Is there ever going to be some kind of parallelism in Ethereum or any L2?

Suppose I have a long array of values: x = [1, 2, 3, ..., N] # shape [N, ] array and a function def f(x): return x ** 2 then I'd do something like (similar to python's multiprocessing) with ...
H. Arponen's user avatar
3 votes
2 answers
560 views

Finality of Optimistic Rollups

In the documentation for optimism (which is transparent about being somewhat incomplete at this experimental stage in their development), it is stated that "It's important to note that a ...
Paul's user avatar
  • 67
1 vote
0 answers
92 views

How to generate a proof for a Cairo program and verify it?

In SNARKs, you can use Zokrates or snarkjs to generate a proof for a program/computation and verify it, locally or on Ethereum. Similar to this unanswered question, how to do the same in Cairo and ...
sinoTrinity's user avatar
1 vote
0 answers
32 views

Understanding data availability for zk rollups

My understanding is that if a zkrollup operator suddenly ceases operation, you have to sync the rollup’s history from genesis to get the current state. In other words, if the transaction data has been ...
Zingo's user avatar
  • 11
2 votes
0 answers
195 views

How works fault-proof in Optimistic rollups L2

I want to understand how works fault-proof concept in Optimistic rollups L2. I have made tests on Optimism and Arbitrium's testnets. It works fine but i want to know how i can revoke a transaction ...
Bob5421's user avatar
  • 1,505
2 votes
1 answer
113 views

Does a Rollup transaction need the parameter 'nonce'?

Recently I am learning Rollups, and one thing makes me confused is that, Does the compressed transaction in a batch need the parameter nonce? Here in on-chain-scaling-to-potentially-500-tx-sec-through-...
shiiu akiyama's user avatar
3 votes
0 answers
59 views

What is the role of a circuit in zero knowledge rollups

I am a student currently pursuing my bachelors degree in technology, for my final year project. I am trying to create a zk-rollup poc for nfts, I have came across different implementation of rollup ...
Srivatsan's user avatar
1 vote
0 answers
32 views

Cant decode specific transaction input from rollups appendSequencerBatch method

I can easly decode some standard methods and their inputs to get method name and all the parametars but this one specific I cant and all I get is { method: 'appendSequencerBatch', types: [], inputs: []...
Blissful's user avatar
  • 355
3 votes
1 answer
61 views

How will transactions be assigned to a shards in Ethereum PoS?

I understand that the plan is to have shards with Ethereum PoS. I am trying to have a mental picture of how that will work. Basically when a wallet signs a transaction, what determines which shard of ...
Finlay Weber's user avatar