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

> function _ validate_ evm_ arguments(auth_ args: list<gtv>, required_ flags: set<text>, account: account , auth_ descriptor: account_ auth_ descriptor ): ev

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

FUNCTION

# \_validate\_evm\_arguments

```signature
function _validate_evm_arguments(auth_args: list<gtv>, required_flags: set<text>, account: account, auth_descriptor: account_auth_descriptor): evm_auth_args
```

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/core/auth/authentication.rell#lines-398)

Verifies that the arguments passed to the `evm_auth` operation are valid.

Throws `"INPUT ERROR"` if the param passed in `auth_args` has any number of elements other
than three.

Throws `"UNAUTHORIZED ACCESS"` if the auth descriptor does not have the necessary flags to
authorize this operation.

**Parameters**

* **auth\_args** — the arguments passed to `evm_auth`
* **required\_flags** — the flags that this operation requires
* **account** — the account that the user authenticated as
* **auth\_descriptor** — the auth descriptor the user is authorizing with

**Returns**

an object containing the validated arguments for `evm_auth`

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