Key Management

Manage the ECDH keypairs used to encrypt and decrypt market maker offers in the RFQ system.

Why Keys Matter

Every RFQ you create includes your ECDH compressed public key. Market makers use it to encrypt their offers so that only you can decrypt them (sealed-bid privacy). The corresponding private key must be available when you want to:

• Decrypt an offer for early settlement

• Debug a decryption failure by comparing stored vs on-chain public keys

If you lose your private key, you cannot decrypt any offers made against RFQs that used the corresponding public key. There is no recovery mechanism.

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Storage Providers

The SDK automatically selects a storage provider based on your runtime environment:

Environment	Default Provider	Persistence	Location
Node.js	internal file storage	Persistent	.thetanuts-keys/ directory (permissions 0o600)
Browser	explicit provider required	App-defined	Use encrypted/passphrase-backed storage; plaintext localStorage is not the default
Testing	MemoryStorageProvider	Lost on exit	In-memory only

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Automatic Key Management

The simplest usage: call getOrCreateKeyPair() and the SDK handles everything.

import { ethers } from 'ethers';
import { ThetanutsClient } from '@thetanuts-finance/thetanuts-client';

const provider = new ethers.JsonRpcProvider('https://mainnet.base.org');
const client = new ThetanutsClient({ chainId: 8453, provider });

// Returns existing keypair from storage, or generates and stores a new one
const keyPair = await client.rfqKeys.getOrCreateKeyPair();
console.log('Public Key:', keyPair.compressedPublicKey);
// Keys are saved automatically and survive process restarts (Node.js)

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Custom Storage Provider

Node.js persists keys to ./.thetanuts-keys/ automatically. To use a different backend, pass any object that implements KeyStorageProvider:

import { ThetanutsClient } from '@thetanuts-finance/thetanuts-client';
import type { KeyStorageProvider } from '@thetanuts-finance/thetanuts-client';

const customStorage: KeyStorageProvider = {
  async get(keyId) { return myStore.get(keyId); },
  async set(keyId, privateKey) { await myStore.set(keyId, privateKey); },
  async remove(keyId) { await myStore.delete(keyId); },
  async has(keyId) { return myStore.has(keyId); },
};

const client = new ThetanutsClient({
  chainId: 8453,
  provider,
  keyStorageProvider: customStorage,
});

const keyPair = await client.rfqKeys.getOrCreateKeyPair();

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Memory Storage (Testing Only)

Use MemoryStorageProvider in tests or CI environments where you don't need persistence:

import { ThetanutsClient, MemoryStorageProvider } from '@thetanuts-finance/thetanuts-client';

// WARNING: Keys are LOST when the process exits!
const client = new ThetanutsClient({
  chainId: 8453,
  provider,
  keyStorageProvider: new MemoryStorageProvider(),
});

The SDK logs a warning when MemoryStorageProvider is used, as a reminder that the keys will not persist.

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Custom Storage Provider

Implement KeyStorageProvider to store keys in a database, cloud secret manager, or any other backend:

import { KeyStorageProvider } from '@thetanuts-finance/thetanuts-client';

class MyDatabaseStorage implements KeyStorageProvider {
  async get(keyId: string): Promise<string | null> {
    return await myDatabase.get(keyId);
  }

  async set(keyId: string, privateKey: string): Promise<void> {
    await myDatabase.set(keyId, privateKey);
  }

  async remove(keyId: string): Promise<void> {
    await myDatabase.delete(keyId);
  }

  async has(keyId: string): Promise<boolean> {
    return await myDatabase.exists(keyId);
  }
}

const client = new ThetanutsClient({
  chainId: 8453,
  provider,
  keyStorageProvider: new MyDatabaseStorage(),
});

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Key Backup Warning

CRITICAL: Back up your RFQ private keys. If lost, you cannot decrypt offers made to your public key. There is no recovery mechanism.

• Node.js: Keys are in .thetanuts-keys/ with 0o600 permissions — back up this directory

• Browser: pass an explicit keyStorageProvider; do not store production RFQ private keys in plaintext localStorage

Export for Backup

// Export private key (store this somewhere secure)
const privateKeyHex = await client.rfqKeys.exportPrivateKey();
console.log('Backup this key:', privateKeyHex);

Import from Backup

// Restore from a backed-up private key
const keyPair = await client.rfqKeys.importFromPrivateKey(
  privateKeyHex,
  true  // store = true saves it to the configured storage provider
);
console.log('Restored public key:', keyPair.compressedPublicKey);

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RFQKeyManagerModule Method Reference

Method	Description	Requires Signer
generateKeyPair()	Generate a new ECDH keypair (not stored)	No
getOrCreateKeyPair()	Get from storage, or generate and store a new one	No
loadKeyPair()	Load existing keypair from storage	No
hasStoredKey()	Check whether a key exists in storage	No
storeKeyPair(keypair)	Explicitly save a keypair to storage	No
removeStoredKey()	Delete the stored keypair	No
exportPrivateKey()	Export private key hex string for backup	No
importFromPrivateKey(key, store?)	Import a keypair from a private key hex	No
encryptOffer(amount, nonce, pubKey)	Encrypt an offer for a given public key	No
decryptOffer(data, pubKey)	Decrypt an incoming offer using stored private key	No
generateNonce()	Generate a random nonce	No
getPublicKeyFromPrivate(key)	Derive compressed public key from private key	No
isValidPublicKey(key)	Validate a compressed public key format	No
getStorageKeyId()	Get the storage identifier for the current key	No

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Encryption Technical Details

ECDH Key Exchange

The SDK uses secp256k1 ECDH for secure key exchange between requester and market maker:

1. Requester generates keypair:
   - Private key: 32 random bytes
   - Public key: Compressed (33 bytes, 0x02/0x03 prefix)

2. Market Maker generates ephemeral keypair per offer:
   - New keypair for each offer (forward secrecy)

3. Shared secret computation:
   ECDH produces: 0x04 || x-coordinate (32 bytes) || y-coordinate (32 bytes)

4. AES key derivation:
   AES-256 key = x-coordinate (first 32 bytes after 0x04 prefix)
   Note: raw x-coordinate, NOT a SHA256 hash — matches MM bot behavior

5. Encryption:
   Algorithm: AES-256-GCM
   IV: 12 random bytes
   Plaintext: JSON { "offerAmount": "...", "nonce": "..." }
   Output: IV (12 bytes) + ciphertext + auth tag (16 bytes)

Nonce Format

The nonce field in decrypted offers can be in two formats depending on the source:

Source	Format	Example
MM Bot	16-char hex string	"987563ef5fde9655"
SDK	Decimal string	"391788778684598574"

The SDK automatically detects and handles both formats during decryption.

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Key Mismatch Prevention

Common mistakes that cause "Authentication failed" or "KeyNotFoundError":

1. Regenerating keys between RFQ creation and decryption — Always use getOrCreateKeyPair(), never generateKeyPair(), for production flows

2. Running on a different machine without copying .thetanuts-keys/

3. Using MemoryStorageProvider in a long-running process that restarts

Best practices:

• Use getOrCreateKeyPair() for all production RFQ flows

• Back up .thetanuts-keys/ before deploying to new infrastructure

• Verify the stored key matches the on-chain key before attempting decryption:

// Verify key matches the RFQ before decrypting
const keyPair = await client.rfqKeys.loadKeyPair();
const quotation = await client.optionFactory.getQuotation(rfqId);

if (keyPair.compressedPublicKey !== quotation.params.requesterPublicKey) {
  throw new Error('Key mismatch — cannot decrypt offers for this RFQ');
}

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Decryption Troubleshooting

"KeyNotFoundError: RFQ key not found"

• No key in storage for the current keyStorageProvider

• Check that .thetanuts-keys/ exists (Node.js)

• If lost: create a new RFQ with a freshly generated key; old RFQ offers cannot be recovered

"DecryptionError: Invalid ciphertext"

• Wrong private key, or the encrypted offer data is truncated

• Verify encryptedOffer is complete (from the event log, not truncated)

"DecryptionError: Authentication failed"

• AES-GCM auth tag verification failed — shared secret is wrong

• Confirm the stored keypair was used when creating the RFQ (compare public keys)

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See Also

• Create an RFQ — Where getOrCreateKeyPair() is used in context

• Early Settlement — Decrypting an offer to accept it before the deadline

• RFQ Lifecycle — How the sealed-bid auction uses ECDH encryption