Arbitrum Blockchain Anchor Integration

This guide covers the Arbitrum blockchain anchor client integration for TrustWeave. The Arbitrum adapter provides the largest L2 by TVL with EVM compatibility.

Overview

The chains/plugins/arbitrum module provides a complete implementation of TrustWeave’s BlockchainAnchorClient interface using Arbitrum One, the largest Ethereum L2 by TVL. This integration enables you to:

  • Anchor credential digests on Arbitrum with lower fees than Ethereum
  • Benefit from the largest L2 ecosystem by TVL
  • Use EVM-compatible transaction data storage
  • Leverage Ethereum security with L2 scalability

Installation

Add the Arbitrum adapter module to your dependencies:

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dependencies {
    implementation("com.trustweave.chains:arbitrum:1.0.0-SNAPSHOT")
    implementation("com.trustweave:trustweave-anchor:1.0.0-SNAPSHOT")
    implementation("com.trustweave:trustweave-json:1.0.0-SNAPSHOT")
    implementation("com.trustweave:trustweave-core:1.0.0-SNAPSHOT")

    // Web3j for Arbitrum blockchain (EVM-compatible)
    implementation("org.web3j:core:5.0.1")
}

Configuration

Basic Configuration 

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import com.trustweave.anchor.*
import com.trustweave.arbitrum.*

// Create Arbitrum anchor client for mainnet
val options = mapOf(
    "rpcUrl" to "https://arb1.arbitrum.io/rpc",
    "privateKey" to "0x..." // Optional: for signing transactions
)

val client = ArbitrumBlockchainAnchorClient(
    ArbitrumBlockchainAnchorClient.MAINNET,
    options
)

Pre-configured Networks 

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// Arbitrum One mainnet
val mainnetClient = ArbitrumBlockchainAnchorClient(
    ArbitrumBlockchainAnchorClient.MAINNET,
    mapOf(
        "rpcUrl" to "https://arb1.arbitrum.io/rpc",
        "privateKey" to "0x..."
    )
)

// Arbitrum Sepolia testnet
val sepoliaClient = ArbitrumBlockchainAnchorClient(
    ArbitrumBlockchainAnchorClient.ARBITRUM_SEPOLIA,
    mapOf(
        "rpcUrl" to "https://sepolia-rollup.arbitrum.io/rpc",
        "privateKey" to "0x..."
    )
)

SPI Auto-Discovery

When the module is on the classpath, Arbitrum adapter is automatically available:

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import com.trustweave.anchor.*
import com.trustweave.anchor.spi.*
import java.util.ServiceLoader

// Discover Arbitrum provider
val providers = ServiceLoader.load(BlockchainAnchorClientProvider::class.java)
val arbitrumProvider = providers.find { it.name == "arbitrum" }

// Create client
val client = arbitrumProvider?.create(
    ArbitrumBlockchainAnchorClient.MAINNET,
    mapOf("rpcUrl" to "https://arb1.arbitrum.io/rpc")
)

Usage Examples

Anchoring Data 

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import com.trustweave.anchor.*
import com.trustweave.arbitrum.*
import kotlinx.serialization.json.*

val client = ArbitrumBlockchainAnchorClient(
    ArbitrumBlockchainAnchorClient.ARBITRUM_SEPOLIA,
    mapOf(
        "rpcUrl" to "https://sepolia-rollup.arbitrum.io/rpc",
        "privateKey" to "0x..."
    )
)

// Anchor a JSON payload
val payload = buildJsonObject {
    put("digest", "uABC123...")
    put("timestamp", System.currentTimeMillis())
}

val result = client.writePayload(payload, "application/json")
println("Anchored to Arbitrum: ${result.ref.txHash}")

Chain IDs

Network Chain ID RPC URL
Arbitrum One Mainnet eip155:42161 https://arb1.arbitrum.io/rpc
Arbitrum Sepolia Testnet eip155:421614 https://sepolia-rollup.arbitrum.io/rpc

Advantages

  • Largest L2: Highest TVL among Ethereum L2s
  • Lower fees: Significantly cheaper than Ethereum mainnet
  • Fast confirmations: Optimistic rollup with fast finality
  • EVM compatible: Same tools and patterns as Ethereum
  • Ethereum security: Secured by Ethereum mainnet

Integration with TrustWeave 

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import com.trustweave.TrustWeave
import com.trustweave.arbitrum.*

val TrustWeave = TrustWeave.create {
    blockchain {
        register(
            ArbitrumBlockchainAnchorClient.MAINNET,
            ArbitrumBlockchainAnchorClient(
                ArbitrumBlockchainAnchorClient.MAINNET,
                mapOf("rpcUrl" to "https://arb1.arbitrum.io/rpc")
            )
        )
    }
}

Best Practices

  1. Use Arbitrum Sepolia for testing: Always test on Arbitrum Sepolia before using mainnet
  2. Largest ecosystem: Leverage Arbitrum’s large DeFi and dApp ecosystem
  3. Lower fees: Take advantage of Arbitrum’s cost savings
  4. Bridge assets: Use Arbitrum’s official bridge for ETH transfers

Next Steps

References