Storage Best Practices

How to securely store delegated key shares and wallet API keys after decryption.

Recommended: JavaScript SDK with React Hooks

For new React apps, we recommend the JavaScript SDK with React Hooks (@dynamic-labs-sdk/react-hooks) instead of the legacy React SDK documented here. The JS SDK comes with many benefits such as a much smaller bundle size and other optimizations. Use the React quickstart (JavaScript SDK) to get started.

After decrypting the delegated materials, proper storage is critical. The delegatedShare and walletApiKey, in combination with your Dynamic developer API key, provide full signing authority and must be protected with defense-in-depth strategies.

Recommended Storage Approaches

1. Envelope Encryption with Cloud KMS (Recommended)

Use a cloud Key Management Service to encrypt the decrypted materials before storing them in your database.

AWS KMS Example:

import { KMSClient, EncryptCommand, DecryptCommand } from '@aws-sdk/client-kms';

const kmsClient = new KMSClient({ region: 'us-east-1' });

async function encryptWithKMS(plaintext: string, keyId: string) {
  const command = new EncryptCommand({
    KeyId: keyId,
    Plaintext: Buffer.from(plaintext),
  });
  const response = await kmsClient.send(command);
  return response.CiphertextBlob; // Store this in your database
}

async function decryptWithKMS(ciphertext: Uint8Array) {
  const command = new DecryptCommand({
    CiphertextBlob: ciphertext,
  });
  const response = await kmsClient.send(command);
  return Buffer.from(response.Plaintext).toString('utf8');
}

Benefits:

• Centralized key management with automatic rotation
• Hardware-backed security (FIPS 140-2 Level 3)
• Audit logging of all encryption/decryption operations
• Fine-grained IAM policies

2. Google Cloud KMS & Secret Manager

Similar to AWS KMS, but integrated with Google Cloud’s ecosystem.

import { SecretManagerServiceClient } from '@google-cloud/secret-manager';
import { KeyManagementServiceClient } from '@google-cloud/kms';

const secretClient = new SecretManagerServiceClient();
const kmsClient = new KeyManagementServiceClient();

async function storeSecret(projectId: string, secretId: string, payload: string) {
  const [version] = await secretClient.addSecretVersion({
    parent: `projects/${projectId}/secrets/${secretId}`,
    payload: {
      data: Buffer.from(payload, 'utf8'),
    },
  });
  return version.name;
}

3. Azure Key Vault

Microsoft Azure’s managed secrets and key management service.

import { SecretClient } from '@azure/keyvault-secrets';
import { DefaultAzureCredential } from '@azure/identity';

const credential = new DefaultAzureCredential();
const vaultUrl = `https://${vaultName}.vault.azure.net`;
const client = new SecretClient(vaultUrl, credential);

async function storeSecret(name: string, value: string) {
  await client.setSecret(name, value);
}

Security Requirements Checklist

Regardless of your storage method, follow these requirements:

• Never log plaintext materials — redact delegatedShare and walletApiKey from all logs, error messages, and monitoring
• Encrypt at rest — use AES-256-GCM or equivalent; ensure database/storage has encryption enabled
• Encrypt in transit — all communication must use TLS 1.3
• Implement access controls — restrict which services and roles can decrypt materials
• Enable audit logging — track all access to encrypted materials with timestamps and actor identity
• Separate encryption keys — don’t reuse keys across environments (dev/staging/prod)
• Use unique encryption per record — generate new IVs for each encryption operation
• Implement key rotation — rotate encryption keys periodically (e.g., every 90 days)
• Plan for key compromise — document incident response for key material exposure
• Secure deletion — overwrite secrets in memory after use; use secure deletion for storage

Storage Schema Example

CREATE TABLE delegated_shares (
  id UUID PRIMARY KEY,
  user_id VARCHAR(255) NOT NULL,
  wallet_id VARCHAR(255) NOT NULL,
  chain VARCHAR(10) NOT NULL,

  -- Encrypted with KMS/Vault
  encrypted_delegated_share BYTEA NOT NULL,
  encrypted_wallet_api_key BYTEA NOT NULL,

  -- Metadata for key management
  encryption_key_id VARCHAR(255) NOT NULL,
  encryption_algorithm VARCHAR(50) DEFAULT 'AES-256-GCM',

  -- Audit fields
  created_at TIMESTAMP NOT NULL DEFAULT NOW(),
  last_accessed_at TIMESTAMP,
  access_count INTEGER DEFAULT 0,

  -- Indexes
  INDEX idx_user_wallet (user_id, wallet_id),
  INDEX idx_created_at (created_at)
);

What NOT to Do

• Never store plaintext shares in databases, files, or environment variables
• Never commit encryption keys or shares to version control
• Never use the same encryption key across all users
• Never skip signature verification before storing materials
• Never rely solely on database encryption without application-level encryption
• Never expose decrypted materials through APIs or logs