Gdex Authentication

GDEX: Authentication

All GDEX trading uses managed-custody wallets with encrypted computedData payloads. This skill covers both the simple shared-API-key auth and the full managed-custody flow.

When to Use

• Setting up authentication for any trading operation
• Implementing managed-custody sign-in for a control wallet
• Understanding the encryption and signing pipeline
• Troubleshooting auth errors (401, 403, code 103)

Prerequisites

npm install @gdexsdk/gdex-skill

1. Shared API Key Login (Simple)

For agents that need quick access — no wallet signing required:

import { GdexSkill, GDEX_API_KEY_PRIMARY } from '@gdexsdk/gdex-skill';

const skill = new GdexSkill();
skill.loginWithApiKey(GDEX_API_KEY_PRIMARY);
// skill.isAuthenticated() → true

Shared API Keys:

• Primary: 9b4e1c73-6a2f-4d88-b5c9-3e7a2f1d6c54
• Secondary: 2c8f0a91-5d34-4e7b-9a62-f1c3d8e4b705

Read-only endpoints (getTokenDetails, getTrendingTokens, getOHLCV, getTopTraders) do not require any authentication.

2. Managed-Custody Flow (Full Trading)

For trading operations, the full managed-custody flow is:

Generate Session Keypair → Build Sign-In Message → Control Wallet Signs →
Encrypt as computedData → POST /v1/sign_in → Resolve User → Trade

Step-by-Step

import {
  GdexSkill,
  GDEX_API_KEY_PRIMARY,
  generateGdexSessionKeyPair,
  buildGdexSignInMessage,
  buildGdexSignInComputedData,
  buildGdexManagedTradeComputedData,
  buildGdexUserSessionData,
} from '@gdexsdk/gdex-skill';

const skill = new GdexSkill();
skill.loginWithApiKey(GDEX_API_KEY_PRIMARY);
const apiKey = GDEX_API_KEY_PRIMARY;

// Step 1: Generate a secp256k1 session keypair
const { sessionPrivateKey, sessionKey } = generateGdexSessionKeyPair();
// sessionKey = compressed public key (0x + 66 hex chars)

// Step 2: Build the sign-in message
const userId = '0xYourControlWalletAddress'; // EVM address or Solana pubkey
const nonce = String(Math.floor(Date.now() / 1000) + Math.floor(Math.random() * 1000));
const message = buildGdexSignInMessage(userId, nonce, sessionKey);
// → "By signing, you agree to GDEX Trading Terms of Use..."

// Step 3: Sign with control wallet
//   EVM:    wallet.signMessage(message) → EIP-191 personal_sign
//   Solana: nacl.sign.detached(Buffer.from(message)) → base58 encoded
const signature = '...'; // your wallet's signature

// Step 4: Build encrypted computedData and POST to /v1/sign_in
const signInPayload = buildGdexSignInComputedData({
  apiKey, userId, sessionKey, nonce, signature,
});
const signInResult = await skill.signInWithComputedData({
  computedData: signInPayload.computedData,
  chainId: 900, // 900=Solana, 101=Sui, or numeric EVM chain ID
});

// Step 5: Resolve user profile / check managed wallet
const userData = buildGdexUserSessionData(sessionKey, apiKey);
const user = await skill.getManagedUser({ userId, data: userData, chainId: 622112261 }); // Solana
// → { address: "CFSi4YimeCbfSNqH2WmHwJKwj1YYG1cWBtQyVPB4sCe1", chainId: "622112261", ... }

Critical: Solana chainId is 622112261 (ChainId.SOLANA), NOT 900. Using 900 returns the EVM managed address with balance: null. The /v1/user endpoint returns a different managed wallet address per chainId:

• chainId=1 → EVM managed: 0x9967179de55bd67e6b90fcc4f908556d93938c0f
• chainId=622112261 → Solana managed: CFSi4YimeCbfSNqH2WmHwJKwj1YYG1cWBtQyVPB4sCe1 (base58)

Nonce Generation

Nonces are client-generated (not fetched from the server):

const nonce = String(Math.floor(Date.now() / 1000) + Math.floor(Math.random() * 1000));

3. Encryption Details (AES-256-CBC)

All payloads use deterministic AES-256-CBC — no random IV:

import { encryptGdexComputedData, decryptGdexComputedData, deriveGdexAesMaterial } from '@gdexsdk/gdex-skill';

// Encrypt a JSON payload
const cipherHex = encryptGdexComputedData(JSON.stringify({ userId, data, signature, apiKey }), apiKey);

// Decrypt
const plaintext = decryptGdexComputedData(cipherHex, apiKey);

// Get raw key/IV material
const { key, iv } = deriveGdexAesMaterial(apiKey);

Important:

• Trade/sign-in payloads: JSON.stringify(...) → UTF-8 → encrypt → hex
• Session key for /v1/user: raw hex-decoded bytes → encrypt (NOT UTF-8 string; use encryptGdexHexData)
• The API key is included inside the encrypted JSON payload, not just used for encryption
• Do NOT use random IVs or iv:ciphertext format

4. Trade Signing (secp256k1)

Spot trade signatures use raw keccak256 + secp256k1 (no EIP-191 prefix):

import { signGdexTradeMessageWithSessionKey } from '@gdexsdk/gdex-skill';

const signature = signGdexTradeMessageWithSessionKey(
  'purchase',       // action: 'purchase' or 'sell'
  userId,           // lowercase address
  dataHex,          // ABI-encoded trade data (without 0x prefix)
  sessionPrivateKey,
);
// Returns: r(64 hex) + s(64 hex) + v(2 hex) = 130 chars, no 0x prefix
// v = raw recoveryParam (00 or 01), NOT EIP-155 (1b/1c)

Sign-in is the ONLY operation that uses EIP-191 personal_sign with the control wallet.

ABI Encoding Schemas

5. Building Trade Payloads

import { buildGdexManagedTradeComputedData } from '@gdexsdk/gdex-skill';

const trade = buildGdexManagedTradeComputedData({
  apiKey,
  action: 'purchase',  // or 'sell'
  userId: '0xYourAddress',
  tokenAddress: 'DezXAZ8z7PnrnRJjz3wXBoRgixCa6xjnB7YaB1pPB263',
  amount: '100000',     // in smallest unit
  nonce: String(Math.floor(Date.now() / 1000) + Math.floor(Math.random() * 1000)),
  sessionPrivateKey,
});

const result = await skill.submitManagedPurchase({
  computedData: trade.computedData,
  chainId: 900,
  slippage: 1,
});

// Poll trade status
if (result.requestId) {
  const status = await skill.getManagedTradeStatus(result.requestId);
  console.log('Status:', status.status, 'Hash:', status.hash);
}

6. Wallet-Based Auth (Advanced)

For user-owned wallets or browser extensions:

// EVM wallet
await skill.authenticate({
  type: 'evm',
  address: '0xYourAddress',
  privateKey: '0xPrivateKey',
});

// Solana wallet
await skill.authenticate({
  type: 'solana',
  address: 'YourSolanaAddress',
  privateKey: 'base58EncodedPrivateKey',
});

// Custom signer (MetaMask / Phantom)
await skill.authenticate({
  type: 'evm',
  address: accounts[0],
  signer: async (message) =>
    window.ethereum.request({ method: 'personal_sign', params: [message, accounts[0]] }),
});

7. SDK Configuration

const skill = new GdexSkill({
  apiUrl:     'https://trade-api.gemach.io/v1', // Default backend
  timeout:    30000,                             // Request timeout ms
  maxRetries: 3,                                 // Retry on 429/503
  debug:      false,                             // Log requests
});

HTTP headers MUST include a browser User-Agent (e.g., Chrome/91) — non-browser UAs get 403 from Cloudflare. Use Authorization: Bearer <apiKey> header, NOT X-API-Key.

Helper Functions Reference

Common Issues

401 Unauthorized

• API key not set or expired — call skill.loginWithApiKey(apiKey) first
• Session expired — re-authenticate

403 Forbidden

• Non-browser User-Agent header — the SDK handles this automatically
• Using X-API-Key instead of Authorization: Bearer

400 Unauthorized (code 103) on HL operations

• Most common cause: Passing the managed address as walletAddress instead of the control wallet address.
• During sign-in, the session key is registered for the control wallet address (the one that signed the sign-in message).
• All HL write operations (hlCreateOrder, perpDeposit, hlCloseAll, etc.) sign the payload as {action}-{walletAddress}-{data} — if walletAddress doesn't match the sign-in userId, the signature verification fails.
• Fix: Always set walletAddress to the control wallet address used during sign-in, NOT the managed address returned by /v1/user or /v1/sign_in.

// ❌ WRONG — managed address causes code 103
const creds = { apiKey, walletAddress: user.address, sessionPrivateKey };

// ✅ CORRECT — use the control wallet that signed in
const creds = { apiKey, walletAddress: controlWallet.address, sessionPrivateKey };

400 Unauthorized (code 103) on HL operations

• Wrong ABI encoding for the specific HL action — see gdex-perp-trading skill
• Using uint256 instead of uint64 for chainId in hl_deposit
• Wrong signature format (must be raw v=00/01, not EIP-155 v=1b/1c)

Autonomous Agent Notes (Live-Tested)

Complete Auth Flow — Verified Working

import { ethers } from 'ethers';
import {
  GdexSkill, GDEX_API_KEY_PRIMARY,
  generateGdexSessionKeyPair, buildGdexSignInMessage,
  buildGdexSignInComputedData, buildGdexUserSessionData,
} from '@gdexsdk/gdex-skill';

const skill = new GdexSkill();
skill.loginWithApiKey(GDEX_API_KEY_PRIMARY);

// 1. Generate session keypair
const { sessionPrivateKey, sessionKey } = generateGdexSessionKeyPair();

// 2. Sign in with control wallet
const wallet = ethers.Wallet.fromPhrase('your mnemonic phrase...');
const userId = wallet.address;
const nonce = String(Math.floor(Date.now() / 1000) + Math.floor(Math.random() * 1000));
const message = buildGdexSignInMessage(userId, nonce, sessionKey);
const signature = await wallet.signMessage(message);

const signInPayload = buildGdexSignInComputedData({
  apiKey: GDEX_API_KEY_PRIMARY, userId, sessionKey, nonce, signature,
});
await skill.signInWithComputedData({
  computedData: signInPayload.computedData,
  chainId: 1,  // EVM for HL/perps, 622112261 for Solana spot
});

// 3. Resolve managed wallet
const data = buildGdexUserSessionData(sessionKey, GDEX_API_KEY_PRIMARY);
const user = await skill.getManagedUser({ userId, data, chainId: 622112261 });
// user.address = managed Solana wallet (base58)

ChainId for Sign-In Matters

Credentials to Keep Track Of

An autonomous agent must persist these across operations:

• sessionPrivateKey — signs all trade payloads (one per sign-in session)
• sessionKey — used to build encrypted data for read endpoints
• controlAddress (=userId) — the wallet that signed in (used in all API calls)
• managedEvmAddress — from /v1/user?chainId=1 (needed for user_stats only)
• managedSolanaAddress — from /v1/user?chainId=622112261 (for on-chain queries only)

Related Skills

• gdex-onboarding — Platform overview and getting started
• gdex-spot-trading — Buy/sell tokens (requires auth)
• gdex-perp-trading — HyperLiquid perps (requires auth + HL-specific crypto)
• gdex-wallet-setup — Generate control wallets for new users