Asking for a magic string in BLS signature: where does it come from?

[yangby-cryptape]

What happened

I met a problem to sync blocks from a observer node.

It throws an error of invalid signature.

When I tried to write a unit test, I found the magic string "axon".

Before the following line:

axon/core/consensus/src/util.rs

Line 240 in 9a0bdbd

let res = signature.verify(&hash, &aggregate_key, &"axon".into());

There is no string of "axon" is used for creating the signature, why it is used for verifying the signature?

Where does this magic string come from?

I haven't found the original repository ophelia_blst (ref: #1507).

axon/common/crypto/src/lib.rs

Line 6 in 9a0bdbd

pub use ophelia_blst::{BlsPrivateKey, BlsPublicKey, BlsSignature};

[KaoImin]

The origin source is here.
Axon used another bls library which need a common_ref to sign and verify. The current blst library doesn't need this. In order to keep the interface be same, we keep the argument, however, it's useless and we use "axon" to take place.