# Canvas Connect Markdown version of https://l2beat.com/layer2s/projects/canvasconnect ## Summary **Warning:** This project is archived and no longer maintained. **Warning:** Critical contracts can be upgraded by an EOA which could result in the loss of all funds. - Total Value Secured: $194.22 (+0.49% compared to seven days ago; canonically bridged $194.22, 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) - Type: Validium - Purposes: Privacy, Exchange - Host chain: Ethereum ### Risks - Sequencer failure: Force via L1 (sentiment: good) - State validation: Validity proofs (ST) (sentiment: good) - Data availability: External (DAC) (sentiment: bad) - Exit window: None (sentiment: bad) - Proposer failure: Use escape hatch (sentiment: good) ### About Canvas Connect is a Layer 2 solution based on StarkEx technology, specifically designed to provide centralized investment and trading services to financial institutions. ## Value Secured Shown as an interactive chart or widget on [the HTML page](https://l2beat.com/layer2s/projects/canvasconnect#tvs). - [TVS chart (JSON)](https://l2beat.com/api/scaling/tvs/canvasconnect) - [TVS breakdown by token (JSON)](https://l2beat.com/api/scaling/tvs/canvasconnect/breakdown) ## Risk summary **Warning:** Canvas Connect is currently open only to whitelisted institutional clients. ### Funds can be stolen if 1. a contract receives a malicious code upgrade. There is no delay on code upgrades (CRITICAL). ### Funds can be lost if 2. the external data becomes unavailable (CRITICAL). ### Users can be censored if 3. the committee restricts their access to the external data, 4. the operator refuses to include their transactions. However, there exists a mechanism to independently exit the system. ### MEV can be extracted if 5. the operator exploits their centralized position and frontruns user transactions. ## Risk analysis **Warning:** Critical contracts can be upgraded by an EOA which could result in the loss of all funds. **Warning:** Canvas Connect is currently open only to whitelisted institutional clients. ### Sequencer failure Force via L1 (sentiment: good) Users can force the sequencer to include a transaction by submitting a request through L1. If the sequencer censors or is down for for more than 7d, users can use the exit hatch to withdraw their funds. ### State validation Validity proofs (ST) (sentiment: good) STARKs are zero knowledge proofs that ensure state correctness. ### Data availability External (DAC) (sentiment: bad) Proof construction relies fully on data that is NOT published onchain. There exists a Data Availability Committee (DAC) with a threshold of 1/2 that is tasked with protecting and supplying the data. ### 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 Use escape hatch (sentiment: good) Users are able to trustlessly exit by submitting a Merkle proof of funds. NFTs will be minted on L1 to exit. ## Data availability ### Data is not stored on chain The balances of the users are not published onchain, but rather sent to external trusted parties, also known as committee members. A state update is valid and accepted onchain only if at least a quorum of the committee members sign a state update. **Risks** - Funds can be lost if the external data becomes unavailable (CRITICAL). - Users can be censored if the committee restricts their access to the external data. **References** - [Data Availability Modes - StarkEx documentation](https://docs.starkware.co/starkex/con_data_availability.html#data_availability_modes) - [Validium - StarkEx documentation](https://docs.starkware.co/starkex/con_data_availability.html#validium_starkex) - [Availability Verifiers - StarkEx documentation](https://docs.starkware.co/starkex/spot/shared/contract-management.html#availability_verifiers_spot) ## State validation ### Validity proofs Each update to the system state must be accompanied by a ZK proof that ensures that the new state was derived by correctly applying a series of valid user transactions to the previous state. These proofs are then verified on Ethereum by a smart contract. The system state is represented using Merkle roots. **References** - [Enforcing Consistency on the On-Chain State - StarkEx documentation](https://docs.starkware.co/starkex/spot/shared/README-off-chain-state.html#enforcing_consistency_in_the_on_chain_state_spot) ## Upgrades & Governance ## Updates Shown as an interactive chart or widget on [the HTML page](https://l2beat.com/layer2s/projects/canvasconnect#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. Typically, the Operator is the hot wallet of the StarkEx service submitting state updates for which proofs have been already submitted and verified. **Risks** - MEV can be extracted if the operator exploits their centralized position and frontruns user transactions. **References** - [Operator - StarkEx documentation](https://docs.starkware.co/starkex/perpetual/shared/contract-management.html#operator_perpetual) ### Users can force exit the system Force exit allows the users to escape censorship by withdrawing their funds. The system allows users to force the withdrawal of funds by submitting a request directly to the contract onchain. The request must be served within a defined time period. If this does not happen, the system will halt regular operation and permit trustless withdrawal of funds. **Risks** - Users can be censored if the operator refuses to include their transactions. However, there exists a mechanism to independently exit the system. **References** - [Censorship Prevention - StarkEx documentation](https://docs.starkware.co/starkex/architecture/solution-architecture.html#8-censorship-prevention) ## Withdrawals ### Regular exit The user initiates the withdrawal by submitting a regular transaction on this chain. When the block containing that transaction is settled the funds become available for withdrawal on L1. ZK proofs are required to settle blocks. Finally the user submits an L1 transaction to claim the funds. When withdrawing NFTs they are minted on L1. **References** - [Withdrawal - StarkEx documentation](https://docs.starkware.co/starkex/spot/withdrawal.html) ### Forced exit If the user experiences censorship from the operator with regular exit they can submit their withdrawal requests directly on L1. The system is then obliged to service this request. Once the force operation is submitted and if the request is serviced, the operation follows the flow of a regular exit. **References** - [Forced Operations - StarkEx documentation](https://docs.starkware.co/starkex/spot/shared/README-forced-operations.html) - [Full Withdrawal - StarkEx documentation](https://docs.starkware.co/starkex/spot/spot-trading-full-withdrawals.html) ### Emergency exit If the enough time deadline passes and the forced exit is still ignored the user can put the system into a frozen state, disallowing further state updates. In that case everybody can withdraw by submitting a merkle proof of their funds with their L1 transaction. **References** - [Forced Operations - StarkEx documentation](https://docs.starkware.co/starkex/spot/shared/README-forced-operations.html) - [Full Withdrawal - StarkEx documentation](https://docs.starkware.co/starkex/spot/spot-trading-full-withdrawals.html) ## Permissions ### Ethereum #### Actors ##### SHARP Multisig Addresses: [0x21F9eC47b19d95b5C2DDFB6Ae5D4F92fAdacAEc4](https://etherscan.io/address/0x21F9eC47b19d95b5C2DDFB6Ae5D4F92fAdacAEc4) A Multisig with 2/4 threshold. * Can upgrade **with 8d delay** * SHARPVerifierCallProxy [via: - acting directly with 8d delay] * Can interact with SHARPVerifierCallProxy * Administer the CallProxy's `GOVERNANCE_ADMIN` and role-admin hierarchy. This AccessControl role is separate from the outer proxy governor that schedules implementation upgrades * Grant and revoke application roles, including the `APP_GOVERNOR` role that controls caller-specific fallback routes * Route fallback calls from specific callers to a still-active registry in the default verifier's reference chain. This principally determines which verifier and bootloader configuration processes their proof submissions; the proxy's explicit `isValid` entry point always queries the default target ##### EOA 1 Addresses: [0xc7C731AF62Cd43eB158ad3Ac0fC5d2dd32648C7A](https://etherscan.io/address/0xc7C731AF62Cd43eB158ad3Ac0fC5d2dd32648C7A) * Can upgrade **with no delay** * StarkExchange * Can interact with StarkExchange * manage the token admin role * Permissioned to appoint and remove the Operator, register additional verifier and availability verifier contracts (removals are delayed), set the default vault withdrawal lock, unfreeze the exchange and manage the governor set ##### 2 EOAs Addresses: [0x107691bD4F590270B9793c807cB912DD278e8cB5](https://etherscan.io/address/0x107691bD4F590270B9793c807cB912DD278e8cB5) (EOA 2), [0x5751a83170BeA11fE7CdA5D599B04153C021f21A](https://etherscan.io/address/0x5751a83170BeA11fE7CdA5D599B04153C021f21A) (EOA 4) * Can interact with StarkExchange * Permissioned to regularly update the state roots of the L2 on L1. Each state update must have been proven via the SHARP verifier and contains commitments to the data that is itself kept offchain ##### EOA 3 Addresses: [0x3e10FD04BfCE4dBF496d72F39172347Bf887ac1D](https://etherscan.io/address/0x3e10FD04BfCE4dBF496d72F39172347Bf887ac1D) * Can interact with StarkExchange * Can regsiter new tokens for deposits and withdrawals ## Smart contracts ### Ethereum #### StarkExchange Addresses: [0x7A7f9c8fe871cd50f6Ce935d7c7caD2e89987f9d](https://etherscan.io/address/0x7A7f9c8fe871cd50f6Ce935d7c7caD2e89987f9d#code), [0xdF2f24751F7e84ccDCD39e7b49904FAB0Fb0f583](https://etherscan.io/address/0xdF2f24751F7e84ccDCD39e7b49904FAB0Fb0f583#code) (Implementation #1 (Upgradable)), [0xfbea22FeB369DB10C0d3a2aAa8F4939E76815f12](https://etherscan.io/address/0xfbea22FeB369DB10C0d3a2aAa8F4939E76815f12#code) (Implementation #2 (Upgradable)), [0x2Dbc18A3ac126abE1fF90A83Bbc3947ff7912Afb](https://etherscan.io/address/0x2Dbc18A3ac126abE1fF90A83Bbc3947ff7912Afb#code) (Implementation #3 (Upgradable)), [0x67e198743BC19fa4757720eDd0e769f8291e1F1D](https://etherscan.io/address/0x67e198743BC19fa4757720eDd0e769f8291e1F1D#code) (Implementation #4 (Upgradable)), [0x613ee54C54D5548627064B4D648942bF3648f376](https://etherscan.io/address/0x613ee54C54D5548627064B4D648942bF3648f376#code) (Implementation #5 (Upgradable)), [0xb2ED005D0278179001a49a9969BB22BA8e98f31F](https://etherscan.io/address/0xb2ED005D0278179001a49a9969BB22BA8e98f31F#code) (Implementation #6 (Upgradable)), [0xB5353268d8d4D711a92cb838F8fEDFC2A66E50Db](https://etherscan.io/address/0xB5353268d8d4D711a92cb838F8fEDFC2A66E50Db#code) (Implementation #7 (Upgradable)), [0xc7C731AF62Cd43eB158ad3Ac0fC5d2dd32648C7A](https://etherscan.io/address/0xc7C731AF62Cd43eB158ad3Ac0fC5d2dd32648C7A#code) (Admin) Central Validium contract. Receives (verified) state roots from the Operator, allows users to consume L2 -> L1 messages and send L1 -> L2 messages. Critical configuration values for the L2's logic are defined here by various governance roles. * Roles: * **admin**: EOA 1 * **operators**: EOA 2, EOA 4 * **tokenAdmins**: EOA 3 Can be upgraded by: EOA 1 with no delay #### DACommittee Addresses: [0x8B3A6662809195453645e37C2005d655f57ca818](https://etherscan.io/address/0x8B3A6662809195453645e37C2005d655f57ca818#code) Data Availability Committee (DAC) contract verifying and storing data availability claims from DAC Members (via a multisignature check). The threshold of valid signatures is 1. #### CpuVerifierAllSolidity_2026_13 Addresses: [0x015381651F240Ed6C44122dCba6Cf807c9442CD6](https://etherscan.io/address/0x015381651F240Ed6C44122dCba6Cf807c9442CD6#code) Immutable Solidity verifier for one Cairo CPU layout. It checks the STARK proof using layout-specific constraint, OODS, Merkle, FRI, and periodic-column helper contracts. The SHARP verifier can select any configured layout by `cairoVerifierId`. #### CpuVerifierDex_2026_13 Addresses: [0x0cD0cDf0132c566db61B691BCEEBA2c4D8cA5CdC](https://etherscan.io/address/0x0cD0cDf0132c566db61B691BCEEBA2c4D8cA5CdC#code) Immutable Solidity verifier for one Cairo CPU layout. It checks the STARK proof using layout-specific constraint, OODS, Merkle, FRI, and periodic-column helper contracts. The SHARP verifier can select any configured layout by `cairoVerifierId`. #### CairoBootloaderProgram Addresses: [0x24105e6697AdD9B4B1BDE04079a91BDFCCa24A47](https://etherscan.io/address/0x24105e6697AdD9B4B1BDE04079a91BDFCCa24A47#code) Stores the complete compiled Cairo outer bootloader used as the top-level program of a SHARP proof. The SHARP verifier copies these words into public memory, pinning this exact executable onchain independently of the separately committed simple, applicative, and recursive-verifier programs. #### CpuVerifierRecursive_2026_13 Addresses: [0x2867A4509B0969531641A42a3D4A9B0A07109B6B](https://etherscan.io/address/0x2867A4509B0969531641A42a3D4A9B0A07109B6B#code) Immutable Solidity verifier for one Cairo CPU layout. It checks the STARK proof using layout-specific constraint, OODS, Merkle, FRI, and periodic-column helper contracts. The SHARP verifier can select any configured layout by `cairoVerifierId`. #### CpuVerifierSmall_2026_13 Addresses: [0x30F3AB988Cb00fe3Fb5ab891F50c13684770419b](https://etherscan.io/address/0x30F3AB988Cb00fe3Fb5ab891F50c13684770419b#code) Immutable Solidity verifier for one Cairo CPU layout. It checks the STARK proof using layout-specific constraint, OODS, Merkle, FRI, and periodic-column helper contracts. The SHARP verifier can select any configured layout by `cairoVerifierId`. #### MemoryPageFactRegistry_2023_9 Addresses: [0x40864568f679c10aC9e72211500096a5130770fA](https://etherscan.io/address/0x40864568f679c10aC9e72211500096a5130770fA#code) Permissionless commitment calculator and registry used by the Solidity STARK verifiers. Anyone may submit a public-memory page and interaction elements; the contract computes its hash and cumulative product and registers the fact key committing to them, which the CPU verifier must bind to the proof. It is part of the proof verifier, not an application-level program registry. A malicious or nonconforming implementation can break public-memory soundness; binding to a different honest registry generally causes a liveness failure instead. #### SHARPVerifierCallProxy Addresses: [0x47312450B3Ac8b5b8e247a6bB6d523e7605bDb60](https://etherscan.io/address/0x47312450B3Ac8b5b8e247a6bB6d523e7605bDb60#code), [0x3597c5CBCbCB30079a0bD2A68cDE5f98272f9feb](https://etherscan.io/address/0x3597c5CBCbCB30079a0bD2A68cDE5f98272f9feb#code) (Implementation (Upgradable)), [0x21F9eC47b19d95b5C2DDFB6Ae5D4F92fAdacAEc4](https://etherscan.io/address/0x21F9eC47b19d95b5C2DDFB6Ae5D4F92fAdacAEc4#code) (Admin) Upgradeable call router through which Starknet and other applications access SHARP fact registries. It uses `call`, not `delegatecall`, so facts and immutable verifier configuration remain at each target registry. The explicit `isValid` entry point always queries the default target. Other calls handled by the fallback, principally proof submissions, can be routed per caller to a still-active registry in the default target's reference chain. The default target can be replaced by SHARP Multisig after 8d. * Roles: * **admin**: SHARP Multisig * **appGovernor**: SHARP Multisig * **appRoleAdmin**: SHARP Multisig * **governanceAdmin**: SHARP Multisig Can be upgraded by: SHARP Multisig with 8d delay #### SHARPVerifier Addresses: [0x4956bda1d23F75B988644329c5B06BD1494a72b6](https://etherscan.io/address/0x4956bda1d23F75B988644329c5B06BD1494a72b6#code) Immutable GPS statement verifier shared by Starknet and other StarkWare systems. It verifies a STARK proof of the exact Cairo bootloader stored onchain, forces the bootloader configuration into public memory, and registers a fact for every bootloader task. A fact is also considered valid when it exists in the time-limited reference fact registry. #### SHARPVerifier_2026_13_1 Addresses: [0x5C1Ce45534A9c5f7F3E6683Cd79a8ad57EE3a9fe](https://etherscan.io/address/0x5C1Ce45534A9c5f7F3E6683Cd79a8ad57EE3a9fe#code) Immutable GPS statement verifier shared by Starknet and other StarkWare systems. It verifies a STARK proof of the exact Cairo bootloader stored onchain, forces the bootloader configuration into public memory, and registers a fact for every bootloader task. A fact is also considered valid when it exists in the time-limited reference fact registry. #### CpuVerifierDexWithBitwise_2026_13 Addresses: [0x6a67796ee97700B5B5f5aFBCFFDCbc5F80803F11](https://etherscan.io/address/0x6a67796ee97700B5B5f5aFBCFFDCbc5F80803F11#code) Immutable Solidity verifier for one Cairo CPU layout. It checks the STARK proof using layout-specific constraint, OODS, Merkle, FRI, and periodic-column helper contracts. The SHARP verifier can select any configured layout by `cairoVerifierId`. #### CpuVerifierStarknet_2026_13 Addresses: [0x71574057D12541ccDa98643aC56441838353A26D](https://etherscan.io/address/0x71574057D12541ccDa98643aC56441838353A26D#code) Immutable Solidity verifier for one Cairo CPU layout. It checks the STARK proof using layout-specific constraint, OODS, Merkle, FRI, and periodic-column helper contracts. The SHARP verifier can select any configured layout by `cairoVerifierId`. #### SHARPVerifier_2026_13_2 Addresses: [0x7Da1225C752ab37E610a242D9D8a0548262E3fF7](https://etherscan.io/address/0x7Da1225C752ab37E610a242D9D8a0548262E3fF7#code) Immutable GPS statement verifier shared by Starknet and other StarkWare systems. It verifies a STARK proof of the exact Cairo bootloader stored onchain, forces the bootloader configuration into public memory, and registers a fact for every bootloader task. A fact is also considered valid when it exists in the time-limited reference fact registry. #### CpuVerifierRecursiveLargeOutput_2026_13 Addresses: [0xbe0F8F150Fd10798524B4de80eD75751658CAEF3](https://etherscan.io/address/0xbe0F8F150Fd10798524B4de80eD75751658CAEF3#code) Immutable Solidity verifier for one Cairo CPU layout. It checks the STARK proof using layout-specific constraint, OODS, Merkle, FRI, and periodic-column helper contracts. The SHARP verifier can select any configured layout by `cairoVerifierId`. #### MemoryPageFactRegistry Addresses: [0xe583BcDE0160b637330b27a3ea1F3c02ba2eC460](https://etherscan.io/address/0xe583BcDE0160b637330b27a3ea1F3c02ba2eC460#code) Permissionless commitment calculator and registry used by the Solidity STARK verifiers. Anyone may submit a public-memory page and interaction elements; the contract computes its hash and cumulative product and registers the fact key committing to them, which the CPU verifier must bind to the proof. It is part of the proof verifier, not an application-level program registry. A malicious or nonconforming implementation can break public-memory soundness; binding to a different honest registry generally causes a liveness failure instead. #### SHARPVerifier_2026_13_3 Addresses: [0xE67515a751291445B85b2F176c1eCdf08e86b406](https://etherscan.io/address/0xE67515a751291445B85b2F176c1eCdf08e86b406#code) Immutable GPS statement verifier shared by Starknet and other StarkWare systems. It verifies a STARK proof of the exact Cairo bootloader stored onchain, forces the bootloader configuration into public memory, and registers a fact for every bootloader task. A fact is also considered valid when it exists in the time-limited reference fact registry. #### CpuVerifierPerpetual_2026_13 Addresses: [0xFFC7974cd74b95f631f454cd787AAc28F0476b44](https://etherscan.io/address/0xFFC7974cd74b95f631f454cd787AAc28F0476b44#code) Immutable Solidity verifier for one Cairo CPU layout. It checks the STARK proof using layout-specific constraint, OODS, Merkle, FRI, and periodic-column helper contracts. The SHARP verifier can select any configured layout by `cairoVerifierId`. #### GpsFactRegistryAdapter Addresses: [0x5339AB7557b3152b91A57D10B0Caf5da88Db5143](https://etherscan.io/address/0x5339AB7557b3152b91A57D10B0Caf5da88Db5143#code) Adapter between the core contract and the SHARPVerifierCallProxy. Stores the Cairo programHash (`16830627573509542901909952446321116535677491650708854009406762893086223513`). #### OrderRegistry Addresses: [0x806d435a82B0381bD884540c2235147c13B97fe6](https://etherscan.io/address/0x806d435a82B0381bD884540c2235147c13B97fe6#code) Helper contract for registering limit orders from L1. #### CpuFrilessVerifier Addresses: [0x03Fa911dfCa026D9C8Edb508851b390accF912e8](https://etherscan.io/address/0x03Fa911dfCa026D9C8Edb508851b390accF912e8#code), [0x217750c27bE9147f9e358D9FF26a8224F8aCC214](https://etherscan.io/address/0x217750c27bE9147f9e358D9FF26a8224F8aCC214#code), [0x630A97901Ac29590DF83f4A64B8D490D54caf239](https://etherscan.io/address/0x630A97901Ac29590DF83f4A64B8D490D54caf239#code), [0x78Af2BFB12Db15d35f7dE8DD77f29C299C78c590](https://etherscan.io/address/0x78Af2BFB12Db15d35f7dE8DD77f29C299C78c590#code), [0x8488e8f4e26eBa40faE229AB653d98E341cbE57B](https://etherscan.io/address/0x8488e8f4e26eBa40faE229AB653d98E341cbE57B#code), [0x9E614a417f8309575fC11b175A51599661f2Bd21](https://etherscan.io/address/0x9E614a417f8309575fC11b175A51599661f2Bd21#code), [0xC879aF7D5eD80e4676C203FD300E640C297F31e3](https://etherscan.io/address/0xC879aF7D5eD80e4676C203FD300E640C297F31e3#code), [0xe9664D230490d5A515ef7Ef30033d8075a8D0E24](https://etherscan.io/address/0xe9664D230490d5A515ef7Ef30033d8075a8D0E24#code) #### CairoBootloaderProgram_2022_7 Addresses: [0x5d07afFAfc8721Ef3dEe4D11A2D1484CBf6A9dDf](https://etherscan.io/address/0x5d07afFAfc8721Ef3dEe4D11A2D1484CBf6A9dDf#code) #### MemoryPageFactRegistry_2022_7 Addresses: [0xFD14567eaf9ba941cB8c8a94eEC14831ca7fD1b4](https://etherscan.io/address/0xFD14567eaf9ba941cB8c8a94eEC14831ca7fD1b4#code) 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).