more info

audits/202311-threat-model-immutable-bridge.md

@@ -14,10 +14,11 @@
 This document is a threat model for a ETH, IMX and ERC20 token bridge that Immutable has built to integrate with the Axelar General Message Passing (GMP) bridge. The token bridge was forked from Polygon Edge's RootERC20Predicate and ChildERC20Predicate contract available [here](https://github.com/0xPolygon/core-contracts) with most of the Edge-specific functionality removed leaving a standard ERC20 token bridge.
 
 The features of the changes introduced are:
-- Support for native ETH and ERC20 bridging from Ethereum (L1) to Immutable zkEVM (L2).
+- Support for native ETH, IMX and ERC20 bridging from Ethereum (L1) to Immutable zkEVM (L2).
   - Native ETH is represented on Immutable zkEVM as an ERC20 token. 
   - wETH will be auto-unwrapped on Ethereum before bridging it across as native ETH i.e. ETH and wETH will be consolidated to the same ERC20 token on Immutable zkEVM. All users will receive native ETH when withdrawing to Ethereum.
-- Support for native IMX and ERC20 bridging from Immutable zkEVM (L2) to Ethereum (L1).
+  - The bridgeable supply of native IMX on Immutable zkEVM is owned by the `ChildERC20Bridge` contract, the remainder of the bridgeable supply up to the max supply of IMX (2B units) will be held in a treasury safe multi-sig. Increasing the bridgeable supply of native IMX will involve transferring funds directly from the treasury safe to the `ChildERC20Bridge` contract.
+- Support for native ETH, IMX and ERC20 bridging from Immutable zkEVM (L2) to Ethereum (L1).
   - IMX is represented on Immutable zkEVM as the native gas token.
   - IMX is represented on Ethereum as a ERC20 token, see [here](https://etherscan.io/token/0xf57e7e7c23978c3caec3c3548e3d615c346e79ff).
   - As a result, a wIMX ERC20 token contract will be deployed for compatibility and usage with our Seaport and DEX contract.
@@ -28,9 +29,26 @@ The features of the changes introduced are:
 - Decouple our token bridge contracts from Axelar to future proof a change of the GMP to a zk-proof-based bridge
 - The sender and receiver of bridged tokens can be different addresses.
 - Flow rate integration for withdrawals from Immutable zkEVM to Ethereum
+  - An account with `PAUSER` role can pause all deposits and withdrawals.
+  - An account with `UNPAUSER` role can unpause all deposits and withdrawals.
+  - A withdrawal queue is defined. In certain situations, a crosschain transfer
+    results in a withdrawal being put in a "queue". Users can withdraw the amount
+    after a delay. The default delay is one day. The queue is implemented as an
+    array. Users can choose which queued withdrawals they want to process.
+  - An account with `RATE` role can enable or disable the withdrawal queue, and
+    configure parameters for each token related to the withdrawal queue.
+  - Withdrawals of tokens whose amount is greater than a token specific threshold are
+    put into the withdrawal queue. This just affects an individual withdrawal. It does
+    not affect other withdrawals by that user or by any other user.
+  - Withdrawals are put into the withdrawal queue when no thresholds have been defined
+    for the token being withdrawn. This just affects an individual withdrawal. It does
+    not affect other withdrawals by that user or by any other user.
+  - If the rate of withdrawal of any token is over a token specific threshold, then all
+    withdrawals are put into the withdrawal queue.
+
 
 Additional Axelar requirements:
-- Axelar will host the relaying service on behalf of Immutable.
+- Axelar will host the relaying service on behalf of Immutable. 
 - We will leverage Axelar's full validator set for the safety and liveness of our bridge.
 - Axelar will provide a one-step bridging experience i.e. there's no need to sign a separate transaction to claim your funds on the destination chain