# account_auth_descriptor · FT4 Rell API · Chromia Docs (concept)

> An entity that allows fine-tuned access control over accounts. It's used to specify
what keypairs can access an account, and it can limit the conditions fo

Source: https://docs.chromia.com/pages/ft4-rell/-f-t4-library/lib.ft4.core.accounts/account_auth_descriptor/

ENTITY

# account\_auth\_descriptor

An entity that allows fine-tuned access control over accounts. It's used to specify
what keypairs can access an account, and it can limit the conditions for access in
some ways.

```signature
entity account_auth_descriptor {
 key id: byte_array;
 key account: account;
 auth_type: auth_type;
 args: byte_array;
 rules: byte_array;
 mutable ctr: integer;
 created: integer;
}
```

`key id: byte_array;`
:   a unique identifier for the auth descriptor

`key account: account;`
:   the account it allows access to

`auth_type: auth_type;`
:   whether it's single-sig or multi-sig. It will influence the `args` property.

`args: byte_array;`
:   It specifies signers and level of access for the auth descriptor.
    It should be either of the following structs, encoded into a byte array:

    * `single_sig_args`, if `auth_type` is `S`
    * `multi_sig_args`, if `auth_type` is `M`

`rules: byte_array;`
:   Must be one of these values, converted to gtv and then encoded into a byte array:

    * **no rules**: `null` (when encoded, it will be converted to `GTV_NULL_BYTES`)
    * **a simple rule**: a `rule_expression`
    * **a complex rule**: a list starting with the value `"and"` and followed by
      `rule_expression`s

    The amount of rule expressions should always be less than or equal to
    `auth_descriptor_config.max_rules`.

    After the expiration conditions are reached, this auth descriptor
    will automatically be deleted as soon as the account that owns it sends an
    operation.

    Must be `GTV_NULL_BYTES` if this is the `main_auth_descriptor` for the account.

    **See Also**

    * [`rule_expression`] — explains what it means to expire

`mutable ctr: integer;`
:   Used for the `op_count` expiration rule, counts how many operations this auth
    descriptor has authenticated.

`created: integer;`
:   When was this auth descriptor registered

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/core/accounts/module.rell#lines-144)

[View this page on docs.chromia.com](https://docs.chromia.com/pages/ft4-rell/-f-t4%20-library/lib.ft4.core.accounts/account_auth_descriptor/index.html)Generated API reference, mirrored from the live docs