Creating a Self-Verifying Client (SPV) in Ethereum: A Step-by-Step Guide
As an independent node, you can run the SPV client to verify and download blocks from the Ethereum network without relying on centralized exchanges or nodes. This provides greater control and flexibility in blockchain research.
In this article, we will look at the steps necessary to create an SPV client and synchronize with the Ethereum network.
What is a Self-Verifying Customer (SPV)?
A self-verifying client (SPV) is a software component that acts as an intermediary between a user’s client and the main Ethereum network. Using the SPV client, you can verify the integrity of your blocks without relying on a centralized node.
Step 1: Download Ethereum Blockchain
Before creating an SPV client, make sure you have downloaded the latest blockchain data for the Ethereum network. You can use tools like geth or ethers.js to download block headers and transaction hashes.
Here’s an example of how to create a basic SPV client using geth':
Create a new directory for your SPV clientmkdir etcd
Install gethget npm install -g
Download the latest blockchain data for Ethereumgeth downloadblockchain --datadir ./data
Step 2: Setting up the Bloom Filter
To configure Bloom filters, you will need to create a bloomfilter.jsonfile in your./data/directory. This file will store information about the addresses you want to check.
Create the following files:
{
"addresses": {
"0x1234567890abcdef": true,
"0x234567890abcdef1": false
}
}
This configuration tells bloomfilter.jsonto mark the address0x1234567890abcdefas verified.
Step 3: Connect to a peer
To synchronize with peers, you need to create an SPV client with your preferred peer protocol (for example, JSON-RPC or Websocket). This will allow you to connect to several nodes and check blocks independently.
Here is an example usingethers.js:
const ethers = require('ethers');
// Create a new instance of the Ethereum provider
const provider = new ethers.providers.JsonRpcProvider('
// Define an SPV client with your preferred host protocol (e.g. JSON-RPC or Websocket)
const spvCustomer = new ethers.SpvCustomer(provider, {
// Set Bloom filter configuration for address 0x1234567890abcdef
bloomFilter: {
address: [
'0x1234567890abcdef'
],
value: true
}
});
Step 4: Download all block headers from the last checkpoint
After configuring the SPV client and connecting it to the peer, you can start downloading block headers from the last checkpoint.
Here is an example of using geth:
Load all block headers from the last checkpointgeth downloadblockchain --datadir ./data --maxBlockNumber 1000000
Step 5: Re-request each block with…
To make sure that your SPV client is working correctly, you will need to request each block again. This ensures that the client has received all blocks since the last checkpoint.
Here is an example using ethers.js`:
// Load all block headers from the last checkpoint
geth downloadblockchain --datadir ./data --maxBlockNumber 1000000
// Request each block again with...
const geth = new ethers.SpvClient(provider, {
// Set Bloom filter configuration for address 0x1234567890abcdef
bloomFilter: {
addresses: [
'0x1234567890abcdef'
],
value: true
}
});
// Load all block headers from the last checkpoint again
geth downloadblockchain --datadir ./data --maxBlockNumber 1000001
By following these steps, you can create a self-verifying client (SPV) on Ethereum and verify the integrity of your blocks without relying on centralized nodes.
