TxAllowList Precompile - Nyxor Protocol

What is `TxAllowList`?

On Nyxor L1, access control is not implemented inside Solidity application logic. Instead, it is enforced at the consensus mempool boundary by the stateful TxAllowList precompile at:

0x0200000000000000000000000000000000000002

Why Consensus Precompiles Over Smart Contract KYC?

Traditional EVM smart contract permissioning uses modifiers like require(isWhitelisted[msg.sender]). This introduces two severe vulnerabilities for institutional trading:

Zero Wasted Gas on Reverts: When an unauthorized entity attempts to submit a transaction, the node drops the packet immediately. No block space is consumed, and no gas is charged.
Mempool Denial-of-Service Defense: Non-whitelisted bots cannot spam the mempool to delay or frontrun institutional keeper liquidations.
Regulatory Isolation: Provides institutional partners with proof that un-KYC’d addresses cannot broadcast to the execution layer.

Precompile Roles

The precompile assigns an integer role to each 20-byte address:

Role Value	Designation	Capabilities
`Role 0`	`None` / Restricted	Transactions rejected immediately at the node boundary.
`Role 1`	`Enabled` / Transactor	Cleared to broadcast transactions, trade perps, and transfer tokens.
`Role 2`	`Admin`	Authority to call `setEnabled()`, `setAdmin()`, and `setNone()`.

Solidity Interface

interface ITxAllowList {
    function readAllowList(address addr) external view returns (uint256 role);
    function setEnabled(address addr) external;
    function setAdmin(address addr) external;
    function setNone(address addr) external;
}