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

> function validate_ blockchain_ rid(blockchain_ rid: byte_ array, descriptor: text) Checks whether the blockchain RID has the correct size Throws "INVALID B

Source: https://docs.chromia.com/pages/ft4-rell/-f-t4-library/lib.ft4.utils/validate_blockchain_rid/

FUNCTION

# validate\_blockchain\_rid

```signature
function validate_blockchain_rid(blockchain_rid: byte_array, descriptor: text)
```

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/utils/utils.rell#lines-95)

Checks whether the blockchain RID has the correct size

Throws `"INVALID BRID"` if the RID's length is not 32 bytes.

Should be used inside other functions, and the `descriptor` parameter should be passed
in a way that the error message is understood by the end users.

Example: `validate_blockchain_rid(x"", "Chain X's RID")`
will throw this error: `"INVALID BRID: Chain X's RID cannot be empty"`

**Parameters**

* **blockchain\_rid** — The RID to check
* **descriptor** — the name of the parameter for nicer error printing

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