> ## Documentation Index
> Fetch the complete documentation index at: https://sdk.avantisfi.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Security Model

> Key permissions, digest verification, and what can never happen.

## What an API key can and cannot do

An API key (delegate) signs orders; it does not hold or control funds.

| Action                                    | API key                                                   |
| ----------------------------------------- | --------------------------------------------------------- |
| Open, close, and modify positions         | Allowed                                                   |
| Set TP/SL, place limit and TWAP orders    | Allowed                                                   |
| Withdraw or transfer USDC                 | **Impossible** (funds live in your wallet)                |
| Approve USDC spending                     | **Blocked** (trader key only)                             |
| Add or remove other delegates             | **Blocked** (trader key only)                             |
| Referral, claims, LP vault, builder codes | **Blocked** (caller-scoped, SDK raises before submission) |

Delegations expire (`expiry_seconds`) and can be revoked at any time from the UI or via `revoke_delegate`. Revocation also kills in-flight intents. The worst a leaked API key can do is trade on your account until you revoke it.

## Signing safety

* **Digest verification.** For every intent, the SDK computes the EIP-712 digest locally and asserts it equals the API-provided digest before signing. A mismatch raises `DigestMismatchError` and nothing is submitted. This means a compromised or buggy API cannot trick the SDK into signing something other than what you asked for.
* **Golden vectors.** All 17 intent kinds are tested against signature vectors produced by the on-chain hashing library itself (the two off-chain-verified kinds, `TwapCancelReq` and `CancelOffchainOrder`, are pinned to ethers `TypedDataEncoder` digests), so local encoding provably matches the verifiers.
* **EIP-7702 parity.** The relayer passthrough's smart-account encoding is tested byte-for-byte against the Gelato reference implementation.

## Key handling

* The SDK never transmits private keys; only signatures leave the process.
* `register_delegate` uses the trader key for a single transient signature; it is not stored on the client.
* For production custody, plug in a `KmsSigner` (or any `BaseSigner`) so raw key material never touches the host. See [Configuration](/configuration#custom-signers).

## Recommended setup

1. Generate an API key with the [Avantis API Key Generator](https://delegate.avantisfi.com/); never put your wallet key on a server.
2. Set a finite `expiry_seconds` and rotate keys periodically.
3. Call `verify_delegation()` at startup to fail fast on revoked/expired keys.
4. Keep only trading USDC in the wallet the bot operates on.