FAQ
Frequently asked questions about Veil.
General
What is Veil?
Veil is a privacy-preserving payment protocol for Solana. It enables scheduled payments where recipient lists are hidden using Merkle trees and executed privately in TEE via MagicBlock Ephemeral Rollups.
Why use Veil?
On-chain payments are fully transparent. Veil hides recipient lists and amounts while maintaining on-chain verification through Merkle proofs.
Is Veil open source?
Yes, Veil is fully open source. See our GitHub repository.
Privacy
What information is public?
- Vault addresses
- Schedule PDAs
- Merkle roots (32 bytes)
- Total recipient count
- Execution intervals
What information is private?
- Individual recipient addresses
- Individual payment amounts
- Recipient order/index
- Merkle proofs (stored off-chain)
How does privacy work?
Recipient lists are stored as Merkle roots on-chain. Individual claims are executed privately in TEE via MagicBlock ER, so recipient lists are never exposed.
Technical
What tokens are supported?
Currently, a single SPL token mint configured in the global VeilConfig (e.g. USDC on devnet). The program enforces that all vaults and deposits use this allowed_mint.
How many recipients per schedule?
Configurable, default is 1024. Check maxRecipients in config.
What’s the execution interval?
Any interval >= 1 hour. Common intervals:
- Daily: 86400 seconds
- Weekly: 604800 seconds
- Monthly: ~2592000 seconds
How does batch execution work?
When a schedule is due:
- Coordinator delegates to ER
- Recipients claim with Merkle proofs (private)
- Batch completes when all claim OR timeout
- State committed back to Solana
Coordinator
Do I need to run a coordinator?
For automatic execution, yes. You can also manually execute claims if you have ER authority.
Can multiple coordinators run?
Yes, but they should coordinate to avoid duplicate executions. Future versions will support distributed coordination.
What happens if coordinator goes down?
Schedules will pause until coordinator resumes. No funds are lost.
Security
Are funds safe?
Yes. Funds are stored in program-controlled vaults. Only the employer can withdraw available balance.
Can recipients claim multiple times?
No. Each recipient can only claim once per batch using a paid bitmap.
What if Merkle proof is wrong?
Invalid proofs are rejected on-chain. Only valid recipients with correct proofs can claim.