Highway Protocol

Executive Summary

The blockchain ecosystem has evolved into a multi-chain environment where assets, logic, and users operate across heterogeneous networks such as Solana, Mosaic, Ethereum, and other sovereign chains. Yet today's cross-chain infrastructure remains fragmented, centralized, and economically inefficient.

Highway introduces a decentralized, multi-chain message relaying protocol built on a cryptographically verifiable committee architecture. The network is powered by a globally distributed relayer network, where infrastructure participants provide critical infrastructure services for secure cross-chain message delivery.

Problem Statement

Cross-chain interoperability remains Web3's greatest architectural and economic bottleneck. Despite major advances in sovereign blockchain design, the infrastructure that connects these chains is still inadequate.

Immature Cross-Chain Architecture

Existing bridges treat messages as edge cases rather than fundamental components. Different blockchains operate under different consensus and finality guarantees:

• Solana — optimistic finality
• Mosaic/Substrate — deterministic finality
• Ethereum — economic finality
• BSC — probabilistic finality

Legacy bridges do not account for these differences, resulting in fragile designs and unsafe assumptions. Developers must build chain-specific logic for every cross-chain pairing.

Infrastructure Centralization

Fewer than 10 operators control the majority of RPC, indexing, and infrastructure platform, creating chokepoints that undermine decentralization. Applications face vendor lock-in, single points of failure, geographic concentration risks, and high operational costs.

Economic Inefficiencies

Cross-chain operations are expensive, slow, and vulnerable to MEV extraction. Liquidity is fragmented across chains — value locked in isolated pools, inconsistent pricing, and thin bridging markets that block mainstream adoption.

Protocol Overview

Highway is a decentralized cross-chain messaging system with BFT committee validation, enabling secure message passing between sovereign chains. Rather than relying on centralized bridges, Highway introduces a BFT verification system powered by a distributed relayer network.

Highway supports three core message operations: cross-chain token transfers, cross-chain arbitrary message execution, and composed operations (token transfer + payload execution in one atomic flow).

System Architecture

Source Chain Components

The Entry Contract on the source chain serves as the origin point for all cross-chain operations, supporting three modes:

• Token Transfer Mode: lock/burn tokens and emit cross-chain event
• Message Passing Mode: send arbitrary payloads and function calls
• Token + Payload Mode: composed operations for complex DeFi flows

Mosaic Chain: Coordination Layer

Mosaic acts as Highway's verification and coordination hub, hosting two core pallets:

• Verifier Pallet: validates committee signatures, enforces relay authority rules
• Registry Pallet: stores the full relayer set, tracks active relayers, manages hourly updates

Destination Chain Components

The Executor Contract validates committee signatures and executes token transfers, function calls, or composed operations atomically. The Registry Contract stores the active relayer set, updated hourly.

Relayer Network

Relayers monitor source chains for events, form committees for message validation, and deliver messages to destination chains. They operate under deterministic message assignment and committee selection logic.

Message Operations

Token Transfer Methods

Composed Operations

Token transfer + message payload execution in a single atomic operation. If the target contract call fails, the token transfer reverts. Applications include cross-chain swaps, multi-chain coordination, asset routing, and composed DeFi operations.

Deterministic Message Assignment

Relayers compute deterministic message assignment that ensures automatic load balancing and failover:

• Primary relayer: 0–6 seconds execution window
• Secondary relayer: 7–12 seconds if primary hasn't claimed
• Tertiary relayer: 13+ seconds failover

Committee-Based Validation

For each message transfer, a committee of 128 relayers is selected deterministically. 86 signatures (⅔ threshold) are required for validation using BLS signature aggregation. Validation occurs in two phases:

• Source validation: job claiming by relayers
• Execution validation: confirmation of successful execution

This dual-phase validation provides cryptographic, deterministic, trust-minimized verification. For every message, a new committee is chosen deterministically, ensuring auditability and decentralization.

Relayer Network

Highway's decentralized infrastructure is powered by a globally distributed network of relay nodes running the Highway Relay OS. The relay software handles message processing

Hardware Requirements

\"Chill\" Mode: Operators can temporarily remove their node from active rotation via the dashboard — no penalties during scheduled maintenance windows.

Security Model

Byzantine Fault Tolerance

• System remains secure if ≤ ⅓ of committee is malicious
• Requires ⅔ + 1 honest committee members (86 out of 128)
• BLS signature aggregation for efficient cryptographic verification

Economic Security

• Relayer infrastructure commitment ensures protocol-level security thresholds are maintained per message
• Misbehaving relayers are permanently excluded from the active relay set
• Every committee is selected deterministically — fully auditable and reproducible

Optimistic Collection Window

Highway extends the BLS signature collection window 3 seconds past the 86th signature threshold, enabling automatic fraud detection. If conflicting signatures are detected within the window, the message is flagged — without requiring second committees, oracles, or additional smart contracts.

Development Roadmap

Team & Partnerships

Bloxico — Lead Development Partner

Highway is developed by Bloxico, a European blockchain technology company specializing in enterprise-grade Web3 infrastructure and validator operations.

• Nenad Tanasković — Co-Founder & CEO
• Robert Paušić — Co-Founder & Fundraising Lead
• Andreja Marković — Blockchain Product Lead
• Todor Todorović — Technical Lead

Mosaic Chain — Technical Integration Partner

Native Substrate integration with the Polkadot ecosystem. Serves as Highway's verification and settlement layer.