> For the complete documentation index, see [llms.txt](https://docs.zk.link/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.zk.link/developer/api-and-sdk/private_key/funding.md).

# Funding

## Encode

| Name              | Rule                                                                                     |
| ----------------- | ---------------------------------------------------------------------------------------- |
| type              | 1 byte, `0x0d`                                                                           |
| accountId         | 4 bytes                                                                                  |
| subAccountId      | 1 byte                                                                                   |
| accountIdNonce    | 4 bytes                                                                                  |
| fundingAccountIds | 4 bytes(when length is 1) or 31 bytes(when length > 1)                                   |
| fee               | 2 bytes, refer to `fee` pack method in [BigUint pack algorithm](#biguint-pack-algorithm) |
| feeToken          | 2 bytes                                                                                  |

The encoding process of `fundingAccountIds` is as blew:

* If the length is 1, encode the item directly in big endian;
* If the length > 1, encode the item in big endian into a bytes list in order;
* Pass the bytes list to the `rescue_hash` function in Rust SDK, and get the 31 bytes result.

## Example

For the `fundingAccountIds` length is 1:

```json
{
  "type": "Funding",
  "accountId": 1,
  "subAccountId": 2,
  "subAccountNonce": 3,
  "fundingAccountIds": [ 1 ],
  "fee": "0",
  "feeToken": 0,
  "signature": {
    "pubKey": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "signature": "00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
  }
}
```

the encode result is:

```json
[13, 0, 0, 0, 1, 2, 0, 0, 0, 3, 0, 0, 0, 1, 0, 0, 0, 0]
```

For the `fundingAccountIds` length is larger than 1:

```json
{
  "type": "Funding",
  "accountId": 1,
  "subAccountId": 2,
  "subAccountNonce": 3,
  "fundingAccountIds": [ 1, 2, 3 ],
  "fee": "0",
  "feeToken": 0,
  "signature": {
    "pubKey": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "signature": "00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
  }
}
encode_bytes = [13, 0, 0, 0, 1, 2, 0, 0, 0, 3, 229, 21, 12, 161, 198, 143, 182, 230, 55, 168, 20, 44, 52, 201, 150, 10, 189, 128, 111, 32, 198, 206, 155, 157, 175, 56, 77, 76, 234, 70, 83, 0, 0, 0, 0]
```