### What is Ethereum BLS Aggregation Signature?

Aggregate signatures work like a petition. Therefore, the petition is sent to each validator who applies their signature.

Thus, to reduce the load on the beacon chain the petitions are sent to their shards. They are only fully built-in the blockchain when the petition has enough support.

So the point of all this is to make it easier for Ethereum to process signature from thousands of validator all at once. Thus, they can increase the numbers of validators by a lot.

### How does BLS Aggregation Signature work?

They use elliptic curve pairings. Hence, Elliptic curve is a mathematic equation. The idea is, that you can create operations. Therefore, messages must be hashed into the elliptic curve pairings. That requires a special hash function. So you have to hash into a point where nobody knows the private key that occurs at that point. Thus, you have a message into the elliptic curve paring. So your private key is a number. Your public key is an elliptic curve point that is responding to the number of the private key.

A signature is when you multiply your private key by the message. So this message is basically an elliptic curve point. If you want to verify a signature, the verification requires an elliptic curve paring check. And for the paring check, you just verify the public key and the message. It then needs to equal the pairing of the generator of the special hash function and the signature.

*How do you aggregate all these signatures?*

**You just add them up.**

### What are the benefits of BLS Aggregation Signature?

With Ethereum BLS Aggregation signature you can reduce finality time, overhead and create more shards. As a result, it is very simple, aside from the complexity of elliptic curve pairings themselves. So it is verifiable because there is only one possible signature per validator and it is friendly to other schemes.

### Summarized:

- So aggregate signatures work like a petition.
- They use elliptic curve pairings.
- To aggregate all signatures you just add them up.
- As a result, they can reduce finality time, overhead and create more shards.