Background

Previously in EIP-2, a new system called trusted borrowing was added to enable wrap / unwrap batcher contracts among other use cases.

The initial batcher contract WrapOnlyBatcher, as the name suggests, allowed for significantly cheaper USDC-to-DSU wrap transactions, however this batcher could not support DSU-to-USDC unwrap transactions, due to the requirement to hold non-reserve USDC.

TwoWayBatcher

We propose a new batcher implementation that supports the permissionless deposit / withdraw of USDC by interested parties to fund the batcher’s supply of USDC.

By holding non-reserve USDC as well as DSU from the reserve’s trusted borrow system, we can then enable bidirectional batching. This primarily serves to enable significantly cheaper DSU-to-USDC unwraps.

Quality of Life

As a housekeeping item, an additional clause to burn any existing ESS held in the reserve has been added on.

Resources

• The Reserve update implementation can be seen here.
• The TwoWay Batcher implementation can be seen here.
• Further discussion here.