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When you set backUpToClientShareService: false during wallet creation, you are responsible for securely storing the externalServerKeyShares returned by createWalletAccount. These key shares, combined with your Dynamic developer API key, provide signing authority and must be protected with defense-in-depth strategies.
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;
}
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);
}

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Security Requirements Checklist

Regardless of your storage method, follow these requirements:
  • Never log plaintext key shares — redact externalServerKeyShares 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 key shares
  • 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

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Storage Schema Example

CREATE TABLE server_wallet_key_shares (
  id UUID PRIMARY KEY,
  wallet_id VARCHAR(255) NOT NULL,
  account_address VARCHAR(255) NOT NULL,

  -- Encrypted with KMS/Vault
  encrypted_key_shares 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_wallet_id (wallet_id),
  INDEX idx_account_address (account_address)
);

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What NOT to Do

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