# Test format: BLS sign message

Message signing with BLS should produce a signature. 

## Test case format

```yaml
input:
  privkey: bytes32 -- the private key used for signing
  message: bytes32 -- input message to sign (a hash)
  domain: bytes    -- BLS domain
output: bytes96    -- expected signature
```

All byte(s) fields are encoded as strings, hexadecimal encoding, prefixed with `0x`


## Condition

The `sign_msg` handler should sign the given `message`, with `domain`, using the given `privkey`, and the result should match the expected `output`.