> For the complete documentation index, see [llms.txt](https://docs-zkevm.cronos.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs-zkevm.cronos.com/for-developers/using-zkcro-veth-and-vusd/vusd.md). # vUSD {% hint style="danger" %} **Notice: Cronos zkEVM is being sunset, please** [**bridge out your assets**](/for-developers/using-zkcro-veth-and-vusd/vusd.md#l2-greater-than-l1-withdrawing-usddai-from-usdvusd) **before the network is fully decommissioned.** {% endhint %} [#l2-greater-than-l1-withdrawing-usddai-from-usdvusd](#l2-greater-than-l1-withdrawing-usddai-from-usdvusd "mention") ## \[L2 -> L1] Withdrawing $DAI from $vUSD *From Cronos zkEVM mainnet (L2) -> Ethereum mainnet (L1)* {% hint style="info" %} For withdrawing $vUSD (Cronos zkEVM Mainnet) and get $DAI (Ethereum Mainnet) , we would need to: 1. \[On Cronos zkEVM] Use $vUSD to redeem $ybUSD; 2. \[On Cronos zkEVM] Bridge $ybUSD to Ethereum; 3. \[On Ethereum] Redeem $ybUSD for $DAI {% endhint %} To redeem $vUSD from `Cronos zkEVM mainnet -> Ethereum mainnet`, and withdraw $DAI we would need to interact with the following contracts: * $vUSD token contract * Cronos zkEVM: [`0x5b91e29Ae5A71d9052620Acb813d5aC25eC7a4A2`](https://explorer.zkevm.cronos.org/address/0x5b91e29Ae5A71d9052620Acb813d5aC25eC7a4A2) * `L2Bridge` * Cronos zkEVM: [0x309429DE3621992Cb0ab8982A448c9Cc5c38405b](https://explorer.zkevm.cronos.org/address/0x309429DE3621992Cb0ab8982A448c9Cc5c38405b) * zk Chain Shared Bridge * Ethereum: [0xD7f9f54194C633F36CCD5F3da84ad4a1c38cB2cB](https://etherscan.io/address/0xD7f9f54194C633F36CCD5F3da84ad4a1c38cB2cB) * $ybUSD token contract * Ethereum: [0xFA59075DfCE274E028b58BdDFcC3D709960F594a](https://etherscan.io/address/0xFA59075DfCE274E028b58BdDFcC3D709960F594a) * Cronos zkEVM: [`0xb1Ece5b548766215272BAFCfa36396B06Cd9e4C9`](https://explorer.zkevm.cronos.org/address/0xb1Ece5b548766215272BAFCfa36396B06Cd9e4C9) ### Step 1) Approving $vUSD to be spend by vUSD contract On Cronos zkEVM, call `approve` on the $vUSD contract to approve $vUSD spend with appropriate amount. ### Step 2) Redeeming $vUSD for $ybUSD On Cronos zkEVM, call `redeem` on the vUSD contract, to burn $vUSD and redeem $ybUSD ``` function redeem( address _receiver, uint256 _vUsdAmount ) ``` | Parameters | Comments | | ------------- | --------------------------------------------------- | | `_receiver` | Address to receive $ybUSD on Cronos zkEVM | | `_vUsdAmount` | Amount of vUSD that will be burned to redeem $ybUSD | Once done, corresponding $ybUSD will be transfer to the `_reciever` address ### Step 3) Approving $ybUSD to be spend by the L2Bridge On Cronos zkEVM, call `approve` on the ybUSD contract, to approve L2Bridge contract to spend $ybUSD. ### Step 4) Withdrawing $ybUSD and store withdrawal hash On Cronos zkEVM, call `withdraw` on the L2Bridge contract ``` function withdraw( address _l1Receiver, address _l2Token, uint256 _amount ) ``` | Parameters | Comments | | ------------- | --------------------------------------------------------------------------------- | | `_l1Receiver` | Address on Ethereum to receive the token | | `_l2Token` | The token to be withdrawn, the Cronos zkEVM contract address $ybUSD in this case. | | `_amount` | amount of tokens to be withdrawn, note $ybUSD has `18` decimals | Keep the transaction hash for later use in Step 5. This withdraws $ybUSD from Cronos zkEVM to Ethereum. It takes 24 hours before the withdrawal can be finalized on Ethereum. Store the transaction hash from the withdrawal transaction; it will be needed to finalize the withdrawal. ### Step 5) Gathering information for $ybUSD withdrawal on L1 Extra information for the L2 -> L1 transaction is required for the next step in claiming the $ybUSD. This information can be gathered by [finalizeWithdrawalParams](https://docs.zksync.io/sdk/js/ethers/api/v5/accounts/wallet#finalizewithdrawalparams), using `zksync-ethers` package ``` finalizeWithdrawalParams(withdrawalHash) ``` This takes the L2 withdrawal hash as parameters and returns the parameters required for finalizing a withdrawal in the next step. Example outputs ``` { l1BatchNumber: 18, l2MessageIndex: 59, l2TxNumberInBlock: 2919, message: '0x6c0960f935f448644c86dbda241ecb57f18a15c80f35a066000000000000000000000000000000000000000000000a2a15d09519be000000', sender: '0x000000000000000000000000000000000000800a', proof: [ '0x23ff0fb003a6a6e111f87cff02afc8680944c711abbe792f07ab4206e9efb9a3', '0x09fece9c46307f2a0976a3a9b57873e453cf0f4773c2377dcd19f054166aef22', '0x33c106ae5601983b53c751129d1921c17e40b69aa3fdbfaf07b7a0e0750d35e4', '0x952ffa5de22d99815d9513dd7454949edb2a1cbcf86008f6fa8b169ffe9b4aee', '0x8f10560a0b5412ca2e0578fb9266f55411f357d52c8fc3b2cad43b9877a559a6', '0x8e70b93d3c90798df26473a3ad32a86170e8d52023a4044cf1d4c2d645471b14', '0xdfaacb39891bbbf4509af408239b97a6f5ef715a5c299ba1f3625c20aec4ef8f', '0xb04e5ee349086985f74b73971ce9dfe76bbed95c84906c5dffd96504e1e5396c', '0xac506ecb5465659b3a927143f6d724f91d8d9c4bdb2463aee111d9aa869874db', '0x124b05ec272cecd7538fdafe53b6628d31188ffb6f345139aac3c3c1fd2e470f', '0xc3be9cbd19304d84cca3d045e06b8db3acd68c304fc9cd4cbffe6d18036cb13f', '0xfef7bd9f889811e59e4076a0174087135f080177302763019adaf531257e3a87', '0xa707d1c62d8be699d34cb74804fdd7b4c568b6c1a821066f126c680d4b83e00b', '0xf6e093070e0389d2e529d60fadb855fdded54976ec50ac709e3a36ceaa64c291' ] } ``` ### Step 6) Claiming the $ybUSD on L1 Once the transaction in Step 4 has been finalized, we can claim the withdrawn $ybUSD from the L2Bridge contract by calling its `finalizeWithdrawal` function. The inputs can be found in Step 5, ``` function finalizeWithdrawal( uint256 _chainId, uint256 _l2BatchNumber, uint256 _l2MessageIndex, uint16 _l2TxNumberInBatch, bytes calldata _message, bytes32 calldata _merkleProof ) ``` | Parameters | Comments | | -------------------- | -------------------------------------------------------------------------------------------------------- | | `_chainId` | Chain id for Cronos zkEVM, which is `388` | | `_l2BatchNumber` | The L2 batch number where the withdrawal was processed, obtained in Step 5. | | `_l2MessageIndex` | The position in the L2 logs Merkle tree of the l2Log that was sent with the message, obtained in Step 5. | | `_l2TxNumberInBatch` | The L2 transaction number in the batch, in which the log was sent, obtained in Step 5. | | `_message` | The L2 withdraw data, stored in an L2 -> L1 message, obtained in Step 5. | | `_merkleProof` | The Merkle Proof, obtained in Step 5. | Once `finalizeWithdrawal` is completed, the withdrawn amount of $ybUSD will go into the receiver's wallet on Ethereum. We can use `zksync-ethers` package [`isWithdrawalFinalized`](https://docs.zksync.io/sdk/js/ethers/api/v5/accounts/wallet#iswithdrawalfinalized) call to whether the withdrawal transaction is finalized on the L1 network. ``` isWithdrawalFinalized(withdrawalHash) ``` | Parameters | Comments | | ---------------- | ------------------------------------------------------------------------------------------ | | `withdrawalHash` | The transaction hash of the L2 transaction includes the withdrawal transaction from Step 4 | ### Step 7) Approving $ybUSD to be spend by ybUSD contract On Ethereum, call `approve` on the $ybUSD contract, to approve the contract to spend $ybUSD ### Step 8) Redeem $ybUSD for $DAI On Ethereum, call `redeem` on the the $ybUSD contract ``` function redeem( uint256 _amount ) ``` | Parameters | Comments | | ---------- | ---------------------------------------------- | | `_amount` | The amount of $ybUSD tokens to redeem for $DAI | Once `redeem` is completed, the withdrawn amount of $DAI will go into the receiver's wallet on Ethereum.