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

> function verify_ signers(ft_ and_ evm_ signers: list<byte_ array>) Verifies whether provided list of signers have signed the operation/transaction.
FT (GTX

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

FUNCTION

# verify\_signers

```signature
function verify_signers(ft_and_evm_signers: list<byte_array>)
```

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/core/auth/authentication.rell#lines-594)

Verifies whether provided list of signers have signed the operation/transaction.
FT (GTX) signers are checked against GTX `signers` and `signatures` fields, while
EVM signers are checked against signers and signatures provided in
`external.auth.evm_signatures` operation.
Only used when the signers are not part of an auth descriptor, for example when an auth
descriptor is being registered.

Can only be called from an operation.

Throws `"MISSING AUTH OP"` when no auth operation is found to be preceding the current one
but the message template requires the account and/or auth descriptor ID that would be found
there.

Throws if the auth handler for the current operation cannot be found.

Throws if the signers cannot be verified. Common cases are:

* the EVM signers and signatures in `evm_signers` are in different order
* some EVM signers have not signed the message, or any of them have signed a wrong message
* some FT signers did not sign the transaction
* the message for the EVM signers was empty

**Parameters**

* **ft\_and\_evm\_signers** — the signers that are expected to be found.

**See Also**

* [verify\_signers\_with\_message](https://docs.chromia.com/pages/ft4-rell/-f-t4-library/lib.ft4.core.auth/verify_signers_with_message/) — if you need to verify that these signers signed a different message than the one defined in the `auth_handler` for the current operation

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