# How to use CCTP UI for cross-chain deposits to dYdX V4

### What is CCTP?

* Circle’s Cross-Chain Transfer Protocol (CCTP) on Noble enables users to send their USDC, the collateral contemplated by dYdX Chain, from other chains directly to dYdX Chain in an easy, simple and secure manner
* Example: User wants to send their USDC on Polygon to dYdX Chain Solution: By leveraging CCTP, USDC can be burned on Polygon, re-minted on Noble, and forwarded via IBC to dYdX Chain in one transaction. It’s that simple! 

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See: <https://dydx.exchange/blog/cctp>

### How CCTP works

CCTP enables USDC to be sent securely between supported blockchains via a native burn and mint process. There is no reliance on custodial bridging. Here’s an example of a simple CCTP transfer flow:

* User transfers USDC from one chain to another via a third-party app, thereby burning USDC on the source chain (e.g., Polygon)
* Circle’s automated service observes and attests to the burn event
* Either the user or a third party relays the attestation to the destination chain (e.g., Noble)
* User receives USDC on the destination chain (e.g., Noble)&#x20;

### Example: How to bridge USDC using the CCTP UI ( Polygon - Noble)

1. Go to <https://cctp.money/>
2. In order to bridge some USDC from `Polygon` to `dYdX v4` Mainnet, first connect your source wallet (e.g. Metamask). You can swap any fund or from any chain that is made available through `CCTP.` As destination chain, select `Noble.`
3. Next, for the destination address, we need a Noble wallet address, if you already have one, you can just click to connect the Keplr Wallet. \
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   In case you don't:\
   If you have connected a wallet before on <https://dydx.trade/> exchange, you can import that private key into Keplr wallet, in order to get your `Noble` destination address. If not, connect with e.g. Metamask wallet first on [trade](https://dydx.trade/).\
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   Now in order to export your private key, go to  [trade](https://dydx.trade/), click your wallet on the top right and use `export secret phrase.`

<figure><img src="https://2702921872-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FucQvpcxkrpiVlpC8l3qi%2Fuploads%2FmS6zoV4JlRafYHFr7A9G%2FScreenshot%202024-03-25%20at%2016.46.29.png?alt=media&#x26;token=99168a34-ef65-431c-a4f7-a26ea929b421" alt="" width="266"><figcaption></figcaption></figure>

Then on Keplr, click `Import an existing wallet` and copy that secret phrase into Keplr.

<figure><img src="https://2702921872-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FucQvpcxkrpiVlpC8l3qi%2Fuploads%2FXUCTM5kKJ6QSVzUAoVsj%2FScreenshot%202024-03-25%20at%2016.57.24.png?alt=media&#x26;token=4f048baa-408c-49dd-87eb-1677360f1668" alt="" width="375"><figcaption></figcaption></figure>

4. After you have imported a wallet, In the  Keplr wallet interface click, `copy address` and search for `Noble chain`.  Copy your Noble wallet address

<figure><img src="https://2702921872-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FucQvpcxkrpiVlpC8l3qi%2Fuploads%2FFN9TQmbYa3tPbyfAmlMM%2FScreenshot%202024-03-25%20at%2016.57.47.png?alt=media&#x26;token=cf7631a0-0ec4-471c-af1a-fd62fa9f694e" alt="" width="353"><figcaption></figcaption></figure>

5. Now paste this address as the destination address. Fill in the amount of USDC you wish to bridge and click transfer.

<figure><img src="https://2702921872-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FucQvpcxkrpiVlpC8l3qi%2Fuploads%2Fwi1L88nNPLMWAcmt5iuD%2FScreenshot%202024-03-22%20at%2017.45.21.png?alt=media&#x26;token=90734008-5158-4fa8-b856-2a7615f531a3" alt="" width="375"><figcaption></figcaption></figure>

6. Approve the transfer and if all went well, you should see a message that the transfer was approved, followed by a burn and a mint notification on the bottom of your screen.

<figure><img src="https://2702921872-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FucQvpcxkrpiVlpC8l3qi%2Fuploads%2Flf2cAbvKUid0bFWE91Ol%2FScreenshot%202024-03-23%20at%2000.49.52.png?alt=media&#x26;token=f7e358f3-34ca-4fb7-8006-d4f0f7daa010" alt="" width="375"><figcaption></figcaption></figure>

7. Finally on the <https://dydx.trade/> , connect your Metamask wallet with the same secret key you used to transfer to your Noble address. That will initiate the transfer to dYdX chain.\
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   You can now go to Mintscan, fill in your Noble address to check whether the bridging was successful.  If that's the case you should see a `receive, IBC transfer and IBC Acknowledgement transactions`. NOTE that the IBC transfer to dYdX chain may take some time to process.\
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   Once you see the `IBC Ack` happened, you should have received your funds in your dYdX wallet.

<figure><img src="https://2702921872-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FucQvpcxkrpiVlpC8l3qi%2Fuploads%2FgEYuRJFkM3SptfWRnoQQ%2FScreenshot%202024-03-25%20at%2018.44.59.png?alt=media&#x26;token=9658706a-e32f-425a-95c5-a945d1ff6f34" alt=""><figcaption></figcaption></figure>