VM Integration

Overview

To add Warp messaging to a subnet VM, you need to handle message creation on the source side and message verification on the destination side.

Source Chain: Sending Messages

1. Create an Unsigned Message

import "github.com/luxfi/warp"

msg, err := warp.NewUnsignedMessage(
    networkID,     // uint32
    sourceChainID, // ids.ID
    payload,       // []byte (encoded payload)
)

2. Request Signatures

Use a Signer to have the local validator sign the message, or a signature aggregator to collect signatures from multiple validators.

import "github.com/luxfi/warp/signer"

// Local signer (for this validator)
localSigner := signer.NewLocalSigner(blsSecretKey)
sig, err := localSigner.Sign(msg)

3. Aggregate Signatures

The signature aggregator collects individual BLS signatures and produces a single BitSetSignature.

import aggregator "github.com/luxfi/warp/signature-aggregator"

agg := aggregator.New(validatorState, sourceChainID)
signature, err := agg.AggregateSignatures(ctx, msg, quorumNum, quorumDen)

Destination Chain: Receiving Messages

1. Parse and Verify

msg, err := warp.ParseMessage(rawBytes)
if err != nil {
    return err
}

err = warp.VerifyMessage(msg, networkID, validatorState, 67, 100)
if err != nil {
    return err // Insufficient quorum or invalid signature
}

2. Extract Payload

import "github.com/luxfi/warp/payload"

addressedCall, err := payload.ParseAddressedCall(msg.UnsignedMessage.Payload)
// Use addressedCall.SourceAddress and addressedCall.Payload

EVM Precompile

For EVM-based subnets, Warp is accessible via a precompile at a fixed address. Smart contracts can send and receive Warp messages without custom VM modifications.

The precompile handles:

• Sending: Emitting Warp messages from Solidity
• Receiving: Verifying Warp signatures and extracting payloads in Solidity
• Validator queries: Looking up the source chain validator set

Backend

The backend stores outgoing messages and serves them to signature aggregators. Two implementations are provided:

Relayer

The relayer automatically watches for Warp messages on a source chain and delivers them to a destination chain. It handles signature aggregation and transaction submission.