Progressive Privacy

Applications are rarely "all private" or "all public." Real applications evolve. A user might start with a public profile and standard transactions, then upgrade to a "Pro" tier that offers shielded payments.

Veil is designed for this Progressive Privacy model.

Changing Adapters at Runtime

Veil is not a static singleton. It is an instance that can be reconfigured or recreated as application state changes.

Scenario: The Privacy Toggle

Imagine a "Private Mode" toggle in your settings.

Incorrect Approach: Writing if (isPrivate) statements inside every button click handler to call different functions.

Veil Approach: Re-initializing the context when the user changes their preference.

// When the user toggles "Incognito Mode"
function onTogglePrivacy(enabled: boolean) {
  updateVeilConfig({
    // If enabled, prioritize privacy adapters.
    // If disabled, fall back to Noop/Standard adapters.
    mode: enabled ? 'privacy-first' : 'performance-first' 
  });
}

Now, your payment buttons just call veil.send(). They don't know or care which mode is active.

State Boundaries and Pitfalls

When moving between adapters, you must handle Asset Fragmentation.

If a user receives 100 USDC via a Private Adapter, that money is often in a shielded pool account, not their public token account.

If you switch Veil to the NoopPrivacyAdapter (Public Mode), the user might see a balance of 0 USDC, because the public adapter looks at the SPL token account, while the funds are sitting in the private pool.

How to handle this:

1. Unified Balance Hooks: Your UI should sum balances across all known adapters, or clearly distinct "Public Balance" vs "Shielded Balance."
2. Sweeping: When a user disables privacy, you might prompt them to "Unshield" funds—using Veil to send from the private adapter to their own public address.

The Lifecycle

1. Public Default: App starts cheap and fast (Noop).
2. User Upgrade: User needs privacy. Adapter is swapped.
3. Interaction: User transacts. Funds move to shielded pools.
4. Degradation: If the privacy service goes down, Veil can be configured to throw an error or warn the user, preventing them from accidentally sending a public transaction when they expected privacy.

This explicit control over the "failure mode" is critical for maintaining user trust.