# Use a Multi-Signature Scheme

Learn how to use multi-signature schemes to secure cross-chain communication.

Let's explore the use of a Multi-Signature Scheme. We'll take the following steps:

**Generate Two Key Pairs**: We will generate two key pairs.**Sign Message**: We create two Signatures of the same Message with the two Secret Keys.**Aggregate Signatures**: We aggregate the two Signatures to a single Signature.**Aggregate Public Keys**: We aggregate the two Public Keys to a single Public Key.**Verify aggregated Signature**: We verify the Signature with the aggregated Public Key.

### Generate First Key

Start by generating a Key Pair consisting of a Public and Secret Key.

### Sign the Messages

Now use the generated Secret Key to sign a Message.

Enter private key to sign message with

Enter any Message you want to sign with the Private Key

### Generate Second Key

In a real-world setting these key pairs would be created by independent actors, but for the sake of the exercise we will play multiple actors here.

### Sign the Message with the second Key

Make sure to pick exactly the same Message for both Signatures, e.g. "Per consensum ad astra".

Enter private key to sign message with

Enter any Message you want to sign with the Private Key

### Aggregate Signatures

We can now utilize the signature aggregation to create an aggregated Signature. In this exercise we are only aggregating two signatures, but we could do this with hundreds or thousands. Side fact: It does not matter in which order the signatures are aggrated.

Enter the first Signature of the Message.

Enter the second Signature of the Message.

### Aggregate Public Keys

To verify an aggregated Signature, we also need to aggregate the Public Keys that correspond to the Private Keys that were used to sign the message. Analogous to the signatures we can aggregate many more than just two Public Keys and also here the order does not matter.

Enter the first Public Key to aggregate.

Enter the second Public Key to aggregate.

### Verify the Aggregated Signature

Anyone, that has access to the aggregated Public Key can now verify the Signature of the Message. Therefore, the Authenticity, Non-Repudiation and Integrity of the Message can be trusted in an efficient way for a large number of signers.

Enter the Public Key that signed the Message.

Enter the Message that was signed.

Enter the Signature of the Message.

Congrats on going through the exercise and experiencing hands-on how we can utilize Signature Aggregation. You will see in the next chapter about Avalanche Warp Messaging; how Mutli-Signature schemes can enable secure and efficient cross-Subnet communication.