User authentication in the LogX Network involves a series of steps that ensure secure access and interaction with the platform. This comprehensive guide explains the authentication process in detail.
1

Generate Authentication Session Data

The initial step involves generating the authentication session data using the user’s address. This includes creating a session key, sub-account ID, and public key.
2

Register Account

The user’s public key is registered with the platform. This requires generating a digital signature using the user’s private key and a session signature.
3

Send Authentication Request

The final step is sending an authentication request to the LogX Network’s auth API with the necessary data to receive API credentials.

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Authentication Process Details

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1. Generate Authentication Session Data

The authentication process starts by generating session data for the user:
  • sessionKey: Generated using a new Ethereum wallet
  • subAccountIdString: Format: 1_[ethAddress]_1
  • subAccountIdHash: Created by hashing the subAccountIdString
  • publicKey: Derived from the session wallet
This session data forms the basis for subsequent steps and is crucial for establishing a secure session.

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2. Register Account

The next step is to register the account on the LogX Network:
  • A new Ethereum wallet is generated with a public key and a private key
  • A message object is created containing details like:
    • sub-account ID
    • user address
    • session key
    • expiry timestamp
    • nonce
    • chain ID
  • The domain object contains domain-specific data:
    • contract name (“LogX”)
    • version (“1”)
    • chain ID
    • verifying contract address
  • The user signs the message with their Ethereum wallet to generate an ethSignature
  • The private key is used to sign the message again to produce a signingSignature

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3. Send Authentication Request

Finally, the authentication request is sent to the LogX Network’s API: 
// Auth Request Payload
{
  "chainId": 42161,
  "ethAddress": "0xB7FF7301159fB491821Bc126fCfd54dFFC0BbF2f",
  "ethSignature": "0x617ee55cbfe815b08bc3243446e0a5aeb3bf1397f0468d6ef415467f73a48dc207fca5333fe049c0da4032fe8504a2950d751a6f725b04fd3b2829341fe546741c",
  "expiryTs": 1723924122893,
  "nonce": 2,
  "signingKey": "0xC77572f175B541bE7F5273d0fd47F81eBc0b5b37",
  "signingSignature": "0x7a6ca94459031e5829d72ad2bf3978a43298479933797d68362f336203d5a92c72e9dc88793135f26d5a01a74ae7acc8ea0ed7fba33bc85b54870df3471c62cc1b",
  "subaccountId": "1_0xB7FF7301159fB491821Bc126fCfd54dFFC0BbF2f_1"
}
Upon successful registration, the API responds with a logx_key and logx_secret: 
// Auth Response
{
  "body": {
    "logx_key": "f88b017268b7421791f79c9eb07506e2",
    "logx_secret": "268a8bf715dcc1642487805dbb9900665623013828df8eca53f8837818d78e3d"
  },
  "message": "Subaccount successfully registered",
  "status": 200
}
These credentials should be stored securely in local storage for future authentication.

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Implementation Example

Here’s a JavaScript implementation of the authentication process: 
const { ethers } = require('ethers');
const crypto = require('crypto');
const fetch = require('node-fetch');

// API endpoints and contract addresses
const INFRA_BASE_URL = 'https://mainnetapiserverwriter.logx.network';
const INFRA_READER_URL = 'https://mainnetapiserver.logx.network';
const ENDPOINT_CONTRACT_ADDRESS = '0xBC87C2397601391E66adeC581786dF3F8eeE6124';

// Helper function to get subaccount ID
function getSubAccountId(address) {
  const subAccountIdString = `1_${address}_1`;
  const subAccountIdHash = subaccountIdToHex(subAccountIdString);
  return { subAccountIdString, subAccountIdHash };
}

// Convert subaccount ID to hex format
function subaccountIdToHex(subaccountId) {
  const bytes = subaccountIdToBytes32(subaccountId);
  return '0x' + Buffer.from(bytes).toString('hex');
}

// Convert subaccount ID to bytes32 format
function subaccountIdToBytes32(id) {
  const parts = id.split('_');
  const brokerId = parseInt(parts[0], 10);
  const ethAddress = parts[1];
  const subaccountNum = parseInt(parts[2], 10);

  // Validate inputs
  if (isNaN(brokerId) || brokerId >= Math.pow(2, 48)) {
    throw new Error(`Invalid broker ID: ${brokerId}`);
  }
  if (isNaN(subaccountNum) || subaccountNum >= Math.pow(2, 48)) {
    throw new Error(`Invalid subaccount number: ${subaccountNum}`);
  }

  // Convert to bytes
  const first6Bytes = uintTo6Bytes(brokerId);
  const next20Bytes = ethAddressTo20Bytes(ethAddress);
  const last6Bytes = uintTo6Bytes(subaccountNum);

  return [...first6Bytes, ...next20Bytes, ...last6Bytes];
}

// Convert unsigned integer to 6 bytes
function uintTo6Bytes(num) {
  if (num < 0 || num >= Math.pow(2, 48)) {
    throw new Error(`number must be positive or less than 2^48: ${num}`);
  }

  const bytes = [0, 0, 0, 0, 0, 0];
  for (let i = 0; i < 6; i++) {
    bytes[5 - i] = num & 0xff;
    num = num >> 8;
  }
  return bytes;
}

// Convert Ethereum address to 20 bytes
function ethAddressTo20Bytes(address) {
  let cleanAddress = address;
  if (address.startsWith('0x')) {
    cleanAddress = address.slice(2);
  }

  const bytes = Buffer.from(cleanAddress, 'hex');
  if (bytes.length !== 20) {
    throw new Error(
      `invalid address length: expected 20 bytes, got ${bytes.length} bytes`
    );
  }

  return Array.from(bytes);
}

// Get the current nonce from the API
async function getNonce(address) {
  const { subAccountIdHash } = getSubAccountId(address);
  try {
    const res = await fetch(
      `${INFRA_READER_URL}/api/v1/subaccount/nonce/${subAccountIdHash}`,
      {
        headers: {
          'Broker-Id': '1'
        }
      }
    );
    if (!res.ok) {
      throw new Error('Failed to get nonce');
    }

    const data = await res.json();
    return Number(data?.body?.nonce);
  } catch (error) {
    console.error('Error getting nonce:', error);
    throw error;
  }
}

// The definedTypes for EIP-712 signing
const definedTypes = {
  Register: [
    { name: 'subAccountId', type: 'bytes32' },
    { name: 'userAddress', type: 'address' },
    { name: 'sessionKey', type: 'address' },
    { name: 'expiryTimeStamp', type: 'uint128' },
    { name: 'nonce', type: 'uint128' },
    { name: 'chainId', type: 'uint256' }
  ]
};

// Sign with ethers library
async function signWithEthers(privateKey, domain, message, primaryType) {
  const signer = new ethers.Wallet(privateKey);
  const typeDefinition = {
    [primaryType]: definedTypes[primaryType]
  };
  const signature = await signer.signTypedData(domain, typeDefinition, message);
  return signature;
}

/**
 * Main authentication function
 *
 * @param {string} userAddress - Ethereum address to authenticate
 * @param {string} userPrivateKey - Private key corresponding to userAddress
 * @param {number} chainId - Chain ID (e.g., 42161 for Arbitrum One)
 * @returns {Promise<object>} Authentication result with credentials
 */
async function registerAccount(userAddress, userPrivateKey, chainId) {
  try {
    // STEP 1: Generate session data
    console.log('Generating session data...');
    const signer = ethers.Wallet.createRandom();
    const publicKey = signer.address;
    const privateKey = signer.privateKey;

    // STEP 2: Register account
    console.log('Preparing registration data...');
    const { subAccountIdString, subAccountIdHash } = getSubAccountId(userAddress);
    const nonce = await getNonce(userAddress);

    // Prepare the message to sign
    const message = {
      subAccountId: subAccountIdHash,
      userAddress: userAddress,
      sessionKey: publicKey,
      expiryTimeStamp: new Date().getTime() + 6 * 24 * 60 * 60 * 1000, // 6 days
      nonce: nonce,
      chainId: chainId
    };

    // Prepare the domain
    const domain = {
      name: 'LogX',
      version: '1',
      chainId: chainId,
      verifyingContract: ENDPOINT_CONTRACT_ADDRESS
    };

    // Sign with user's Ethereum private key
    console.log('Signing with user private key...');
    const userSigner = new ethers.Wallet(userPrivateKey);
    const ethSignature = await userSigner.signTypedData(
      domain,
      { Register: definedTypes.Register },
      message
    );

    // Sign with session key
    console.log('Signing with session key...');
    const signingSignature = await signWithEthers(
      privateKey,
      domain,
      message,
      'Register'
    );

    // STEP 3: Send authentication request
    console.log('Sending authentication request...');
    const res = await fetch(`${INFRA_BASE_URL}/api/v1/auth`, {
      method: 'POST',
      body: JSON.stringify({
        subaccountId: subAccountIdString,
        signingKey: publicKey,
        signingSignature: signingSignature,
        ethAddress: userAddress,
        ethSignature: ethSignature,
        expiryTs: message.expiryTimeStamp,
        nonce: message.nonce,
        chainId
      }),
      headers: {
        'Content-Type': 'application/json',
        'broker-id': '1'
      }
    });

    if (!res.ok) {
      const errorData = await res.json().catch(() => ({}));
      throw new Error(`Authentication failed: ${errorData.message || res.statusText}`);
    }

    // Process the response
    const responseData = await res.json();
    const account = {
      ...responseData.body, // Contains logx_key and logx_secret
      sessionKey: privateKey,
      publicKey: publicKey,
      expiryTs: message.expiryTimeStamp - 0.5 * 24 * 60 * 60 * 1000 // Expires half a day earlier
    };

    console.log("Authentication successful!");
    return account;
  } catch (error) {
    console.error("Authentication error:", error);
    throw error;
  }
}

​
Handling Credential Expiry

Since authentication credentials expire after 6 days, implement a check to verify if credentials are still valid: 
/**
 * Check if credentials need refresh
 *
 * @param {object} credentials - Object containing expiryTs
 * @returns {boolean} True if refresh needed
 */
function needsRefresh(credentials) {
  if (!credentials || !credentials.expiryTs) return true;

  // Refresh when less than 1 day remains
  const oneDayMs = 24 * 60 * 60 * 1000;
  return Date.now() + oneDayMs > credentials.expiryTs;
}

​
Signing with EIP-712

The signing process uses EIP-712, a standard for typed structured data hashing and signing. It ensures that the signatures are both human-readable and secure, allowing for easier verification on the blockchain.

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Benefits of EIP-712

  • Ensures signatures are typechecked and structured
  • Prevents signature replay attacks
  • Provides better security than raw message signing

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Message Types

LogX Network supports various message types for different operations: 
// Message types for EIP-712
const messageTypes = {
  EIP712Domain: [
    { name: 'name', type: 'string' },
    { name: 'version', type: 'string' },
    { name: 'chainId', type: 'uint256' },
    { name: 'verifyingContract', type: 'address' },
  ],
  Register: [
    { name: 'subAccountId', type: 'bytes32' },
    { name: 'userAddress', type: 'address' },
    { name: 'sessionKey', type: 'address' },
    { name: 'expiryTimeStamp', type: 'uint128' },
    { name: 'nonce', type: 'uint128' },
    { name: 'chainId', type: 'uint256' },
  ],
  // Additional message types for other operations...
}

​
Important Notes

  • Authentication credentials expire after 6 days
  • Store credentials securely and refresh before expiration
  • Never share your privateKey or logx_secret with unauthorized parties
  • The session key is different from your main Ethereum wallet’s private key
  • Always implement proper error handling for authentication failures