# send\_shielded\_transaction

Build, encrypt, sign, and broadcast a shielded transaction.

## Signatures

```python
# sync
w3.seismic.send_shielded_transaction(
    *,
    to: ChecksumAddress,
    data: HexBytes,
    value: int = 0,
    gas: int | None = None,
    gas_price: int | None = None,
    security: SeismicSecurityParams | None = None,
    eip712: bool = False,
) -> HexBytes

# async
await w3.seismic.send_shielded_transaction(...same args...) -> HexBytes
```

## Parameters

| Parameter   | Type                                                                                                                                     | Default  | Description                                     |
| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------- | -------- | ----------------------------------------------- |
| `to`        | `ChecksumAddress`                                                                                                                        | Required | Recipient contract address                      |
| `data`      | `HexBytes`                                                                                                                               | Required | Plaintext calldata (SDK encrypts it)            |
| `value`     | `int`                                                                                                                                    | `0`      | Wei to transfer                                 |
| `gas`       | `int \| None`                                                                                                                            | `None`   | Gas limit (defaults to `30_000_000`)            |
| `gas_price` | `int \| None`                                                                                                                            | `None`   | Gas price in wei (fetched from chain if `None`) |
| `security`  | [`SeismicSecurityParams`](https://docs.seismic.systems/clients/python/api-reference/transaction-types/seismic-security-params) `\| None` | `None`   | Override default security parameters            |
| `eip712`    | `bool`                                                                                                                                   | `False`  | Use EIP-712 typed-data signing path             |

## Returns

`HexBytes` — transaction hash from `eth_sendRawTransaction`.

## Example

```python
from seismic_web3.contract.abi import encode_shielded_calldata

data = encode_shielded_calldata(SRC20_ABI, "transfer", ["0xRecipient", 100])
tx_hash = w3.seismic.send_shielded_transaction(to="0xTokenAddress", data=data)
```

## What's encrypted

The SDK encrypts the `data` field (function selector + arguments) using AES-GCM with the ECDH-derived key. An observer can see `from`, `to`, `value`, and gas parameters, but **not** which function was called or what arguments were passed.

## Notes

* For contract interactions, prefer `contract.write.functionName(...)` which handles ABI encoding and encryption automatically
* Creates a `TxSeismic` (type `0x4a`) transaction
* SDK auto-fetches nonce via `eth_getTransactionCount`

## See Also

* [debug\_send\_shielded\_transaction](https://docs.seismic.systems/clients/python/namespaces/methods/debug-send-shielded-transaction) — Same pipeline with debug artifacts
* [signed\_call](https://docs.seismic.systems/clients/python/namespaces/methods/signed-call) — Read-only equivalent (no state change)
* [contract.write](https://docs.seismic.systems/clients/python/contract/namespaces/write) — High-level contract write API
* [SeismicSecurityParams](https://docs.seismic.systems/clients/python/api-reference/transaction-types/seismic-security-params) — Security parameter reference