> For the complete documentation index, see [llms.txt](https://docs.seismic.systems/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.seismic.systems/clients/python/namespaces/methods/send-shielded-transaction.md).

# send\_shielded\_transaction

Send encrypted TxSeismic 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,
    gas_payment: GasPayment | None = None,
) -> 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 (signed estimate clamped to the final ciphertext admission minimum when omitted; explicit values are preserved) |
| `gas_price`   | `int \| None`                                                                                                   | `None`   | Gas price in wei (fetched from chain if `None`)                                                                           |
| `security`    | [`SeismicSecurityParams`](/clients/python/api-reference/transaction-types/seismic-security-params.md) `\| None` | `None`   | Override default security parameters                                                                                      |
| `eip712`      | `bool`                                                                                                          | `False`  | Use EIP-712 typed-data signing path                                                                                       |
| `gas_payment` | [`GasPayment`](/clients/python/api-reference/transaction-types/gas-payment.md) `\| None`                        | Auto     | Public signed fee choice; explicit Native/Token never falls back                                                          |

## 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)
```

## Automatic gas limits

When `gas` is omitted, both sync and async sends use `max(execution estimate, encrypted-input admission minimum)`. Estimation uses an authenticated, non-broadcastable signed-read twin. The admission minimum is calculated from the **final write ciphertext**, since the twin uses a separate encryption nonce and can have different encrypted bytes.

The current Seismic pool uses Prague intrinsic gas and the calldata gas floor; the SDK applies that bound conservatively on older nodes too. Seismic ignores access-list charges. This avoids rejection of cheap plaintext executions whose encrypted input requires a higher minimum gas limit.

An explicit `gas` value is never increased, even if it is below the pool minimum. A larger automatic limit can increase the upfront fee reserve without charging the entire limit as the final fee. The gas-payment selector and signed-read behavior are unchanged. Contract shielded writes and debug sends share this preparation path.

## 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`, gas parameters, and `gas_payment`, 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](/clients/python/namespaces/methods/debug-send-shielded-transaction.md) — Same pipeline with debug artifacts
* [signed\_call](/clients/python/namespaces/methods/signed-call.md) — Read-only equivalent (no state change)
* [contract.write](/clients/python/contract/namespaces/write.md) — High-level contract write API
* [SeismicSecurityParams](/clients/python/api-reference/transaction-types/seismic-security-params.md) — Security parameter reference


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