Angle Protocol – Staking and Surplus Security Audit

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Summary

Angle implements a decentralized, over-collateralized stablecoin protocol. This report is an extension to the main audit report and reviews the new Angle staking and surplus extension. The staking functionality has been changed completely. The surplus extension introduces an additional fee in the PoolMaster contract where a part of the profit of a strategy is taken as surplus, converted into the selected token and deposited into the FeeDistributor. The FeeDistributor later distributes to veAngle holders (long term admins).

The most critical subjects covered in our audit are the security of the new contracts, the functional correctness and the impact of these changes on the existing system.

Contrary to the extensive documentation which exists for the main Angle Protocol, no documentation exists for the new functionality. This not only makes the understanding of the code more difficult but also prevents this review from cross checking if the implemented behavior matches the expected and documented behavior. Instead we had to make assumptions on the expected behavior. Based on our discussions, we assume that the documentation will be published in a timely manner since the changes impact the agents in the current system, notably the standard liquidity providers.

In the final iteration after the intermediate reports no issues remain open while two issues are acknowledged. The functional correctness is high.

Overall we find that the codebase in its current state provides a high level of security.

About Angle Protocol – Staking and Surplus

“Angle is the first over-collateralized, decentralized and capital-efficient stablecoin protocol. Thanks to the liquidity providers it uses, the protocol proposes full convertibility between stable assets and collateral, meaning that it is possible to swap collateral against stable assets, and stable assets against collateral at oracle value. This makes the protocol not only capital efficient but also highly liquid.

Angle Protocol could be used to issue any stablecoin, and will start at launch on mainnet with a stable Euro. Besides creating the first liquid Euro stablecoin, the goal of Angle is to create stablecoins for almost all Forex currencies, including the US Dollar.”

Source: https://docs.angle.money/whitepaper

Chainsecurity managed to rapidly understand and analyze a code that has been partially forked. They understood in an impressively low amount of time why Angle made changes and how these changes could impact the whole system! Once again, we thank them for their flexibility and rigor!
Pablo Veyrat, Core Contributor @ Angle Protocol