Sending

Shielded transfers send tokens privately from your shielded balance to another Nullmask user.

Requirements

• The recipient must have a registered receiving key on Nullmask

• You must have sufficient shielded balance (amount + fee)

Steps

1. Navigate to the Send screen

2. Select the token

3. Enter the amount

4. Enter or paste the recipient's Ethereum address

5. Confirm the transaction in your wallet

What Happens Behind the Scenes

1. The wallet signs a standard EIP-1559 transfer (e.g., "Send 1 ETH to 0xAlice")

2. The RPC proxy intercepts the transaction

3. The proxy checks that the recipient has a registered receiving key

4. The proxy selects funding notes from your shielded balance

5. A ZK proof is generated proving:

   • You authorized this transfer (ECDSA signature)

   • You have sufficient funds (note ownership + Merkle membership)

   • The output note is correctly encrypted for the recipient

6. The relayer submits the proof to the contract

7. The contract verifies the proof, spends your notes, and creates new notes

Output Notes

Each transfer creates 3 notes:

Note	For	Contains
Output note	Recipient	The transferred amount
Change note	You	Leftover action-asset balance
Fee change note	You	Leftover fee-asset balance

Fee Estimation

Before confirming, the app estimates the fee using nullmask_estimateFee. The fee covers the relayer's gas costs for submitting the transaction on-chain.

Fees can be paid in ETH or the same token being transferred.

Privacy Guarantees

• The on-chain transaction reveals nothing about sender, recipient, or amount

• Only encrypted note ciphertexts are visible on-chain

• The relayer sees only the opaque proof and public inputs