> For the complete documentation index, see [llms.txt](https://docs.arcan.finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.arcan.finance/solidity/acl.md).

# Access list

The access list decides who may use a handle and who may open it. A name that is not on the list never gets the amount.

The list is written from the contract with the `FHE` helpers. The host keeps the list. Coprocessors follow it when they compute and when a decrypt is requested.

## Grant

| Call                                  | Effect                                     |
| ------------------------------------- | ------------------------------------------ |
| `FHE.allow(handle, account)`          | Persistent access for `account`            |
| `FHE.allowThis(handle)`               | Persistent access for the current contract |
| `FHE.allowTransient(handle, account)` | Access for this transaction only           |

`allowThis` is required after you create a new handle the contract must touch again. `allow` is how the holder, an auditor, or another contract receives the handle.

Transient access is for a single transaction. It costs less because it does not stay in storage. Clear it with `FHE.cleanTransientStorage` when the call is done and you do not want the permission to linger.

## Check

| Call                             | Effect                                  |
| -------------------------------- | --------------------------------------- |
| `FHE.isAllowed(handle, account)` | True if `account` may use the handle    |
| `FHE.isSenderAllowed(handle)`    | True if `msg.sender` may use the handle |

Both see persistent and transient grants.

## Deny

`FHE.isAccountDenied` reports whether an account is blocked from encrypted values. A denied account cannot be granted a handle.

## Public decrypt flag

`FHE.makePubliclyDecryptable` puts a handle on the public-decrypt list. After that, anyone can ask for the plaintext. Use it only when the value is meant to become public, such as a final auction price. A balance should not be marked this way.

## Delegation

A contract can delegate its user-decrypt right to another account with `FHE.delegateUserDecryption`. The delegate can open handles the contract could open, until the delegation expires or is revoked. An externally owned account delegates on the access-list contract directly, not through `FHE`, because the caller must be the delegator.

## Pattern for a transfer

```solidity
euint64 nextSender = FHE.sub(balances[from], amount);
euint64 nextRecipient = FHE.add(balances[to], amount);
balances[from] = nextSender;
balances[to] = nextRecipient;
FHE.allowThis(nextSender);
FHE.allowThis(nextRecipient);
FHE.allow(nextSender, from);
FHE.allow(nextRecipient, to);
```

The sender can open their new balance. The recipient can open theirs. The chain still cannot.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://docs.arcan.finance/solidity/acl.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `build a script that syncs our docs to a CMS` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.