Constants

Chain IDs

Network	Underlying Chain ID	Virtual Chain ID
Hardhat (local)	31337	43613
Ethereum Sepolia	11155111	43611
Ethereum Mainnet	1	43615
MegaETH	4326	43616
Arbitrum One	42161	43617
Base	8453	43618
BSC	56	43619

Merkle Tree

Constant	Value	Description
MAX_TREE_DEPTH	16	Maximum Merkle tree depth (will be upgraded to 32)
Maximum leaves	65,536	$2^{16}$ notes
ROOT_HISTORY_SIZE	64	Number of historical roots stored

Field

Constant	Value
BN254 scalar field modulus	21888242871839275222246405745257275088548364400416034343698204186575808495617

Transaction Data Sizes

Parameter	Value	Description
TRANSFER_MAX_DATA_SIZE	68 bytes	ERC-20 transfer calldata (selector + address + amount)
SWAP_MAX_DATA_SIZE	324 bytes	Uniswap V2 router calldata
TRANSFER_RLP_SIZE	143 bytes	RLP buffer for transfer signature verification
SWAP_RLP_SIZE	401 bytes	RLP buffer for swap signature verification

Circuit Public Inputs

Circuit	Public Inputs Count
Shielded Transfer	45 (+ 1 chain_id = 46 total)
Shielded Withdrawal	37 (+ 1 chain_id = 38 total)
Shielded Swap	50 (+ 2 chain_id + router = 52 total)

Note Structure

Field	Type	Description
owner_hash	Field	Hash of receiving key
value	u128	Token amount
coin_id	Field	Token address (0 for ETH)
receiving_key_trapdoor	Field	Masks note owner
value_commitment_trapdoor	Field	Masks note value
nullifiers_hash	Field	Hash of input nullifiers (or deposit index); not stored in note plaintext, passed to commit()

ERC-20 Selectors

Selector	Function
0xa9059cbb	transfer(address,uint256)
0x70a08231	balanceOf(address)

Uniswap V2 Selectors

Selector	Function
0x38ed1739	swapExactTokensForTokens
0x7ff36ab5	swapExactETHForTokens
0x18cbafe5	swapExactTokensForETH

Access Token

Parameter	Value
Cookie name	nullmask_access_token
Token length	16 bytes
Encoding	base64url
Derivation salt	"Nullmask access token"
Hash function	Keccak-256