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

> function require_ evm_ signatures_ can_ be_ used() Ensures that this operation is authorizing an operation which is whitelisted for usage with evm_signatur

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

FUNCTION

# require\_evm\_signatures\_can\_be\_used

```signature
function require_evm_signatures_can_be_used()
```

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/core/auth/module.rell#lines-491)

Ensures that this operation is authorizing an operation which is whitelisted for usage with
`evm_signatures`

The operation that is being authorized should be the next operation in the transaction,
but it's allowed to have an auth operation or a strategy operation between this operation
and the authorized one.

Throws `"EVM SIG FORBIDDEN"` if:

* the operation that is being authorized is not whitelisted,
* there's no operation after this one, or
* there is only one operation after this one, and it's an auth or strategy operation

Can only be called from an operation, and it should only be called by `evm_signatures`

**See Also**

* [is\_evm\_signatures\_authorized\_operation](https://docs.chromia.com/pages/ft4-rell/-f-t4-library/lib.ft4.core.auth/is_evm_signatures_authorized_operation/) — for information on whitelisting operations
* [is\_auth\_op](https://docs.chromia.com/pages/ft4-rell/-f-t4-library/lib.ft4.core.auth/is_auth_op/) — for information on what is an auth operation
* `core.accounts.strategies.is_strategy_op` — for information on what is a strategy operation

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