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Creating a Self-Verifying Client (SPV) on Ethereum: A Step-by-Step Guide
As an independent node, you can run an SPV client to verify and download blocks from the Ethereum network without relying on centralized exchanges or nodes. This allows for greater control and flexibility in your blockchain exploration.
In this article, we will go through the steps required to create an SPV client and sync with the Ethereum network.
What is a Self-Verifying Client (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. By using the SPV client, you can verify the integrity of your blocks without relying on a centralized node.
1. step: download the 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 is an example of how to create a basic SPV client using geth
:
Create a new directory for your SPV clientmkdir etc
Install gethnpm install -g geth
Download the latest blockchain data for Ethereumgeth downloadblockchain --datadir ./data
Step 2: Configure Bloom Filter
To set up 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:
json
{
"addresses": {
"0x1234567890abcdef": true,
"0x234567890abcdef1": false
}
}
This configuration tells
bloomfilter.jsonto mark the address
0x1234567890abcdefas validated.
Step 3: Connecting to a peer
To synchronize with peers, you will need to create an SPV client with the desired node protocol (e.g. JSON-RPC or Websocket). This will allow you to connect to multiple nodes and verify blocks independently.
Here is an example of using
ethers. js:
javascript
const ethers = require('ethers');
// Create a new Ethereum provider instance
const provider = new ethers.providers.JsonRpcProvider('
// Define an SPV client with your preferred node protocol (e.g. JSON- RPC or Websocket)
const spvClient = new ethers.SpvClient(provider, {
// Set bloom filter configuration for address 0x1234567890abcdef
bloomFilter: {
addresses: [
'0x1234567890abcdef'
],
value: true
}
});
Step 4: Downloading all block headers since the last checkpoint
With your SPV client configured and connected to the peer, you can start downloading block headers since the last checkpoint.
Here is an example of using
geth:
just
Download all block headers since the last checkpoint
geth downloadblockchain --datadir ./data --maxBlockNumber 1000000
Step 5: Re-request each block with... To verify that your SPV client is working correctly, you will need to re-request each block. This will ensure that the client has received all blocks since the last checkpoint.
Here is an example of using
ethers.js:
javascript
// Download all block headers since the last checkpoint
geth downloadblockchain --datadir ./data --maxBlockNumber 1000000
// Re-request each block with...
const geth = new ethers .SpvClient(provider, {
// Set bloom filter configuration for address 0x1234567890abcdef
bloomFilter: {
addresses: [
'0x1234567890abcdef'
],
value: true
}
});
// Redownload all block headers since the last checkpoint
geth downloadblockchain --datadir . /data --maxBlockNumber 1000001
``
By following these steps, you can create a self-verified client (SPV) on Ethereum and verify the integrity of your blocks without relying on centralized nodes.