# Form

Markdown version of https://l2beat.com/layer2s/projects/form

## Summary

**Warning:** This project is archived and no longer maintained.

- Total Value Secured: $41.11 K (-3.04% compared to seven days ago; canonically bridged $41.11 K, natively minted $0.00, externally bridged $0.00; 0.00% with additional trust assumptions compared to the tokens involved and the Stage assigned to the project's canonical messaging bridge)
- Gas token: ETH
- Type: Other
- Purposes: Universal, Social
- Host chain: Ethereum
- Chain ID: 478

### Risks

- Sequencer failure: Self sequence (sentiment: good)
- State validation: None (sentiment: bad)
- Data availability: External (sentiment: bad)
- Exit window: None (sentiment: bad)
- Proposer failure: Cannot withdraw (sentiment: bad)

### About

Form is an Optimium utilizing the OP Stack. The Form L2 is focused on bringing mass adoption and interoperability to the SocialFi category.

## Value Secured

Shown as an interactive chart or widget on [the HTML page](https://l2beat.com/layer2s/projects/form#tvs).

- [TVS chart (JSON)](https://l2beat.com/api/scaling/tvs/form)
- [TVS breakdown by token (JSON)](https://l2beat.com/api/scaling/tvs/form/breakdown)

## Activity

Shown as an interactive chart or widget on [the HTML page](https://l2beat.com/layer2s/projects/form#activity).

- [Activity chart (JSON)](https://l2beat.com/api/scaling/activity/form)

## Onchain costs

Shown as an interactive chart or widget on [the HTML page](https://l2beat.com/layer2s/projects/form#onchain-costs).

## Data posted

Shown as an interactive chart or widget on [the HTML page](https://l2beat.com/layer2s/projects/form#data-posted).

## Liveness

Shown as an interactive chart or widget on [the HTML page](https://l2beat.com/layer2s/projects/form#liveness).

## Risk summary

**Warning:** Fraud proof system is currently under development. Users need to trust the block proposer to submit correct L1 state roots.

### Funds can be stolen if

1. a contract receives a malicious code upgrade. There is no delay on code upgrades, (CRITICAL)
2. an invalid state root is submitted to the system (CRITICAL).

### Funds can be lost if

3. the sequencer posts an unavailable transaction root, (CRITICAL)
4. the data is not available on the external provider (CRITICAL).

### Funds can be frozen if

5. the centralized validator goes down. Users cannot produce blocks themselves and exiting the system requires new block production (CRITICAL).

### MEV can be extracted if

6. the operator exploits their centralized position and frontruns user transactions.

## Risk analysis

**Warning:** Fraud proof system is currently under development. Users need to trust the block proposer to submit correct L1 state roots.

### Sequencer failure

Self sequence (sentiment: good)

In the event of a sequencer failure, users can force transactions to be included in the project's chain by sending them to L1. There can be up to a 12h delay on this operation.

### State validation

None (sentiment: bad)

Currently the system permits invalid state roots. More details in project overview.

### Data availability

External (sentiment: bad)

Proof construction and state derivation fully rely on data that is posted on Celestia. Sequencer tx roots are not checked against the Blobstream bridge data roots onchain, but L2 nodes can verify data availability by running a Celestia light client.

### Exit window

None (sentiment: bad)

There is no window for users to exit in case of an unwanted upgrade since contracts are instantly upgradable.

### Proposer failure

Cannot withdraw (sentiment: bad)

Only the whitelisted proposers can publish state roots on L1, so in the event of failure the withdrawals are frozen.

## Data availability

### Data is posted to Celestia

Transactions roots are posted onchain and the full data is posted on Celestia.  Since the Blobstream bridge is not used, availability of the data is not verified against Celestia validators, meaning that the Sequencer can single-handedly publish unavailable roots. If Celestia becomes unavailable, the sequencer falls back to Ethereum.

**Risks**

- Funds can be lost if the sequencer posts an unavailable transaction root (CRITICAL).
- Funds can be lost if the data is not available on the external provider (CRITICAL).

**References**

- [Introducing Blobstream: streaming modular DA to Ethereum](https://blog.celestia.org/introducing-blobstream/)
- [Derivation: Batch submission - OP Mainnet specs](https://github.com/ethereum-optimism/specs/blob/main/specs/protocol/derivation.md#batch-submission)
- [BatchInbox - address](https://etherscan.io/address/0xA77F057914FdC5473dc03dC88E4B84302FA1EEb6#code)
- [OptimismPortal.sol - source code, depositTransaction function](https://etherscan.io/address/0xbdD90485FCbcac869D5b5752179815a3103d8131#code)

## State validation

### No state validation

OP Stack projects can use the OP fault proof system, already being deployed on some. This project though is not using fault proofs yet and is relying on the honesty of the permissioned Proposer and Challengers to ensure state correctness. The smart contract system permits invalid state roots.

**Risks**

- Funds can be stolen if an invalid state root is submitted to the system (CRITICAL).

**References**

- [L2OutputOracle.sol - source code, deleteL2Outputs function](https://etherscan.io/address/0x19652082F846171168Daf378C4fD3ee85a0D4A60#code)

## Upgrades & Governance

## Updates

Shown as an interactive chart or widget on [the HTML page](https://l2beat.com/layer2s/projects/form#updates).

## Operator

### The system has a centralized operator

The operator is the only entity that can propose blocks. A live and trustworthy operator is vital to the health of the system.

**Risks**

- MEV can be extracted if the operator exploits their centralized position and frontruns user transactions.

**References**

- [L2OutputOracle.sol - source code, CHALLENGER address](https://etherscan.io/address/0x19652082F846171168Daf378C4fD3ee85a0D4A60#code)
- [L2OutputOracle.sol - source code, PROPOSER address](https://etherscan.io/address/0x19652082F846171168Daf378C4fD3ee85a0D4A60#code)

### Users can force any transaction

Because the state of the system is based on transactions submitted on the underlying host chain and anyone can submit their transactions there it allows the users to circumvent censorship by interacting with the smart contract on the host chain directly.

**References**

- [Sequencing Window - OP Mainnet Specs](https://github.com/ethereum-optimism/optimism/blob/51eeb76efeb32b3df3e978f311188aa29f5e3e94/specs/glossary.md#sequencing-window)
- [OptimismPortal.sol - source code, depositTransaction function](https://etherscan.io/address/0xbdD90485FCbcac869D5b5752179815a3103d8131#code)

## Withdrawals

### Regular messaging

The user initiates L2->L1 messages by submitting a regular transaction on this chain. When the block containing that transaction is settled, the message becomes available for processing on L1. The process of block finalization takes a challenge period of 7d to complete.

**Risks**

- Funds can be frozen if the centralized validator goes down. Users cannot produce blocks themselves and exiting the system requires new block production (CRITICAL).

**References**

- [OptimismPortal.sol - source code, proveWithdrawalTransaction function](https://etherscan.io/address/0xbdD90485FCbcac869D5b5752179815a3103d8131#code)
- [OptimismPortal.sol - source code, finalizeWithdrawalTransaction function](https://etherscan.io/address/0xbdD90485FCbcac869D5b5752179815a3103d8131#code)
- [L2OutputOracle.sol - source code, PROPOSER check](https://etherscan.io/address/0x19652082F846171168Daf378C4fD3ee85a0D4A60#code)

### Forced messaging

If the user experiences censorship from the operator with regular L2->L1 messaging they can submit their messages directly on L1. The system is then obliged to service this request or halt all messages, including forced withdrawals from L1 and regular messages initiated on L2. Once the force operation is submitted and if the request is serviced, the operation follows the flow of a regular message.

**References**

- [Forced withdrawal from an OP Stack blockchain](https://docs.optimism.io/stack/transactions/forced-transaction)

## Other considerations

### EVM compatible smart contracts are supported

OP stack chains are pursuing the EVM Equivalence model. No changes to smart contracts are required regardless of the language they are written in, i.e. anything deployed on L1 can be deployed on L2.

**References**

- [Introducing EVM Equivalence](https://medium.com/ethereum-optimism/introducing-evm-equivalence-5c2021deb306)

## Permissions

### Ethereum

#### Actors

##### Caldera Multisig 3

Addresses: [0x2bf43034b9559643e986A2fE3cE015a18247b904](https://etherscan.io/address/0x2bf43034b9559643e986A2fE3cE015a18247b904)

A Multisig with 4/7 threshold. 
* Can upgrade **with no delay**
  * L2OutputOracle [via: ProxyAdmin]
  * OptimismPortal [via: ProxyAdmin]
  * L1ERC721Bridge [via: ProxyAdmin]
  * OptimismMintableERC20Factory [via: ProxyAdmin]
  * SuperchainConfig [via: ProxyAdmin]
  * SystemConfig [via: ProxyAdmin]
  * L1StandardBridge [via: ProxyAdmin]
  * L1CrossDomainMessenger [via: ProxyAdmin]
* Can interact with AddressManager
  * set and change address mappings [via: ProxyAdmin]
* Can interact with OptimismPortal
  * Allowed to pause withdrawals. In op stack systems with a proof system, the Guardian can also blacklist dispute games and set the respected game type (permissioned / permissionless) 
* Can interact with SuperchainConfig
  * Allowed to pause withdrawals. In op stack systems with a proof system, the Guardian can also blacklist dispute games and set the respected game type (permissioned / permissionless) 
* Can interact with SystemConfig
  * it can update the preconfer address, the batch submitter (Sequencer) address and the gas configuration of the system 

##### EOA 1

Addresses: [0x76b7C4dfca62E9F44DD4F04b4a14ba9e84Aa5256](https://etherscan.io/address/0x76b7C4dfca62E9F44DD4F04b4a14ba9e84Aa5256)

* Can interact with L2OutputOracle
  * Allowed to challenge or delete state roots proposed by a Proposer 

##### EOA 2

Addresses: [0x8D882B43220A190779c2dF25901f9E089dd4fa7D](https://etherscan.io/address/0x8D882B43220A190779c2dF25901f9E089dd4fa7D)

* Can interact with L2OutputOracle
  * Allowed to post new state roots of the current layer to the host chain 

##### EOA 3

Addresses: [0x5b99FB854eFA37aD4DCbFcCB94af09f5D4CFb32d](https://etherscan.io/address/0x5b99FB854eFA37aD4DCbFcCB94af09f5D4CFb32d)

* Can interact with SystemConfig
  * Allowed to commit transactions from the current layer to the host chain 

## Smart contracts

### Ethereum

#### L2OutputOracle

Addresses: [0x4ccAAF69F41c5810cA875183648B577CaCf1F67E](https://etherscan.io/address/0x4ccAAF69F41c5810cA875183648B577CaCf1F67E#code), [0x19652082F846171168Daf378C4fD3ee85a0D4A60](https://etherscan.io/address/0x19652082F846171168Daf378C4fD3ee85a0D4A60#code) (Implementation (Upgradable)), [0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8](https://etherscan.io/address/0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8#code) (Admin)

Contains a list of proposed state roots which Proposers assert to be a result of block execution. Currently only the PROPOSER address can submit new state roots.
* Roles:
  * **admin**: ProxyAdmin; ultimately Caldera Multisig 3
  * **challenger**: EOA 1
  * **proposer**: EOA 2

Can be upgraded by: Caldera Multisig 3 with no delay

#### OptimismPortal

Addresses: [0x4E259Ee5F4136408908160dD32295A5031Fa426F](https://etherscan.io/address/0x4E259Ee5F4136408908160dD32295A5031Fa426F#code), [0xbdD90485FCbcac869D5b5752179815a3103d8131](https://etherscan.io/address/0xbdD90485FCbcac869D5b5752179815a3103d8131#code) (Implementation (Upgradable)), [0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8](https://etherscan.io/address/0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8#code) (Admin)

The main entry point to deposit funds from host chain to this chain. It also allows to prove and finalize withdrawals.
* Roles:
  * **admin**: ProxyAdmin; ultimately Caldera Multisig 3
  * **guardian**: Caldera Multisig 3

Can be upgraded by: Caldera Multisig 3 with no delay

#### SystemConfig

Addresses: [0x806d48562C224a1332F2De8CCb02DDe8E8a5549E](https://etherscan.io/address/0x806d48562C224a1332F2De8CCb02DDe8E8a5549E#code), [0x67866A5052E5302aaD08e9f352331fd8622eB6DC](https://etherscan.io/address/0x67866A5052E5302aaD08e9f352331fd8622eB6DC#code) (Implementation (Upgradable)), [0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8](https://etherscan.io/address/0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8#code) (Admin)

Contains configuration parameters such as the Sequencer address, gas limit on this chain and the unsafe block signer address.
* Roles:
  * **admin**: ProxyAdmin; ultimately Caldera Multisig 3
  * **batcherHash**: EOA 3
  * **owner**: Caldera Multisig 3

Can be upgraded by: Caldera Multisig 3 with no delay

#### SuperchainConfig

Addresses: [0x7280d2BFd18aa1383C2218E6Bb2964bA8287c66e](https://etherscan.io/address/0x7280d2BFd18aa1383C2218E6Bb2964bA8287c66e#code), [0x068E44eB31e111028c41598E4535be7468674D0A](https://etherscan.io/address/0x068E44eB31e111028c41598E4535be7468674D0A#code) (Implementation (Upgradable)), [0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8](https://etherscan.io/address/0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8#code) (Admin)

This is NOT the shared SuperchainConfig contract of the OP stack Superchain but rather a local fork. It manages the `PAUSED_SLOT`, a boolean value indicating whether the local chain is paused, and `GUARDIAN_SLOT`, the address of the guardian which can pause and unpause the system.
* Roles:
  * **admin**: ProxyAdmin; ultimately Caldera Multisig 3
  * **guardian**: Caldera Multisig 3

Can be upgraded by: Caldera Multisig 3 with no delay

#### L1ERC721Bridge

Addresses: [0x6161C14A37Bc428401A011E5941330cD169a0255](https://etherscan.io/address/0x6161C14A37Bc428401A011E5941330cD169a0255#code), [0x5C4F5e749A61a9503c4AAE8a9393e89609a0e804](https://etherscan.io/address/0x5C4F5e749A61a9503c4AAE8a9393e89609a0e804#code) (Implementation (Upgradable)), [0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8](https://etherscan.io/address/0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8#code) (Admin)

Used to bridge ERC-721 tokens from host chain to this chain.
* Roles:
  * **admin**: ProxyAdmin; ultimately Caldera Multisig 3

Can be upgraded by: Caldera Multisig 3 with no delay

#### L1StandardBridge

Addresses: [0xdc20aA63D3DE59574E065957190D8f24e0F7B8Ba](https://etherscan.io/address/0xdc20aA63D3DE59574E065957190D8f24e0F7B8Ba#code), [0xb7900B27Be8f0E0fF65d1C3A4671e1220437dd2b](https://etherscan.io/address/0xb7900B27Be8f0E0fF65d1C3A4671e1220437dd2b#code) (Implementation (Upgradable)), [0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8](https://etherscan.io/address/0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8#code) (Admin)

The main entry point to deposit ERC20 tokens from host chain to this chain.
* Roles:
  * **admin**: ProxyAdmin; ultimately Caldera Multisig 3

Can be upgraded by: Caldera Multisig 3 with no delay

#### L1CrossDomainMessenger

Addresses: [0xF333158DCCad1dF6C3F0a3aEe8BC31fA94d9eD5c](https://etherscan.io/address/0xF333158DCCad1dF6C3F0a3aEe8BC31fA94d9eD5c#code), [0x094e6508ba9d9bf1ce421fff3dE06aE56e67901b](https://etherscan.io/address/0x094e6508ba9d9bf1ce421fff3dE06aE56e67901b#code) (Implementation (Upgradable)), [0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8](https://etherscan.io/address/0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8#code) (Admin)

Sends messages from host chain to this chain, and relays messages back onto host chain. In the event that a message sent from host chain to this chain is rejected for exceeding this chain's epoch gas limit, it can be resubmitted via this contract's replay function.
* Roles:
  * **admin**: ProxyAdmin; ultimately Caldera Multisig 3

Can be upgraded by: Caldera Multisig 3 with no delay

#### OptimismMintableERC20Factory

Addresses: [0x65f0819c647E06C3191a8b2dd59031259746FB4F](https://etherscan.io/address/0x65f0819c647E06C3191a8b2dd59031259746FB4F#code), [0x39Aea2Dd53f2d01c15877aCc2791af6BDD7aD567](https://etherscan.io/address/0x39Aea2Dd53f2d01c15877aCc2791af6BDD7aD567#code) (Implementation (Upgradable)), [0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8](https://etherscan.io/address/0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8#code) (Admin)

A helper contract that generates OptimismMintableERC20 contracts on the network it's deployed to. OptimismMintableERC20 is a standard extension of the base ERC20 token contract designed to allow the L1StandardBridge contracts to mint and burn tokens. This makes it possible to use an OptimismMintableERC20 as this chain's representation of a token on the host chain, or vice-versa.
* Roles:
  * **admin**: ProxyAdmin; ultimately Caldera Multisig 3

Can be upgraded by: Caldera Multisig 3 with no delay

#### ProxyAdmin

Addresses: [0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8](https://etherscan.io/address/0xb7e0a0507cAfD755B3527Aa1F8b7449222A79Cf8#code)

* Roles:
  * **owner**: Caldera Multisig 3

The current deployment carries some associated risks:

- Funds can be stolen if a contract receives a malicious code upgrade. There is no delay on code upgrades (CRITICAL).