Transmuter is an autonomous and modular price stability module for decentralized stablecoin protocols.
- It is conceived as a basket of different assets (normally stablecoins) backing a stablecoin and comes with guarantees on the maximum exposure the stablecoin can have to each asset in the basket.
- A stablecoin issued through the Transmuter system can be minted at oracle value from any of the assets with adaptive fees, and it can be burnt for any of the assets in the backing with variable fees as well. It can also be redeemed at any time against a proportional amount of each asset in the backing.
Transmuter is compatible with other common mechanisms often used to issue stablecoins like collateralized-debt position models. It should notably be used as a standalone module within the Angle Protocol for agEUR in parallel with the Borrowing module.
The Transmuter system relies on a diamond proxy pattern. There is as such only one main contract (the Transmuter
contract) which delegates calls to different facets each with their own implementation. The main facets of the system are:
- the
Swapper
facet with the logic associated to the mint and burn functionalities of the system - the
Redeemer
facet for redemptions - the
Getters
facet with external getters for UIs and contracts built on top ofTransmuter
- the
SettersGovernor
facet protocols' governance can use to update system parameters. - the
SettersGuardian
facet protocols' guardian can use to update system parameters.
The storage parameters of the system are defined in the Storage
file.
The Transmuter system can come with optional ERC4626 savings contracts which can be used to distribute a yield to the holders of the stablecoin issued through the Transmuter.
The governor role, which will be a multisig or an onchain governance, has all rights, including upgrading contracts, removing funds, changing the code, etc.
The guardian role, which will be a multisig, has the right to: freeze assets, and potentially impact transient funds. The idea is that any malicious behavior of the guardian should be fixable by the governor, and that the guardian shouldn't be able to extract funds from the system.
- Lack of support for ERC165
- At initialization, fees need to be < 100% for 100% exposure because the first exposures will be ~100%
- If at some point there are 0 funds in the system it’ll break as
amountToNextBreakPoint
will be 0 - In the burn, if there is one asset which is making 99% of the basket, and another one 1%: if the one making 1% depegs, it still impacts the burn for the asset that makes the majority of the funds
- The whitelist function for burns and redemptions are somehow breaking the fairness of the system as whitelisted actors will redeem more value
- The
getCollateralRatio
function may overflow and revert if the amount of stablecoins issued is really small (1 billion x smaller) than the value of the collateral in the system.
The Transmuter and savings smart contracts have been audited by Code4rena, find the audit report here.
For contracts deployed for the Angle Protocol, a bug bounty is open on Immunefi and Hats Finance. The rewards and scope of the Angle Immunefi are defined here.
- Transmuter for agEUR on Ethereum: 0x00253582b2a3FE112feEC532221d9708c64cEFAb
This repository is built on Foundry.
If you don't have Foundry:
curl -L https://foundry.paradigm.xyz | bash
source /root/.zshrc
# or, if you're under bash: source /root/.bashrc
foundryup
To install the standard library:
forge install foundry-rs/forge-std
To update libraries:
forge update
You can install all dependencies by running
yarn
forge i
This repository uses ffi
in its test suite. Beware as a malicious actor forking this repo could add malicious commands using this.
In order to interact with non local networks, you must create an .env
that has:
- a
MNEMONIC
for each of the chain you - a network key
- an
ETHERSCAN_API_KEY
For additional keys, you can check the .env.example
file.
Warning:
- always keep your confidential information safe
- this repository uses
ffi
in its test suite. Beware as a malicious actor forking this repo may execute malicious commands on your machine
Compilation of production contracts will be done using the via-ir pipeline.
However, tests do not compile with via-ir, and to run coverage the optimizer needs to be off. Therefore for development and test purposes you can compile without optimizer.
yarn compile # with via-ir but without compiling tests files
yarn compile:dev # without optimizer
Here are examples of how to run the test suite:
yarn test
FOUNDRY_PROFILE=dev forge test -vvv --watch # To watch changing files
FOUNDRY_PROFILE=dev forge test -vvv --match-path test/fuzz/Redeemer.test.sol
FOUNDRY_PROFILE=dev forge test -vvv --match-test "testAbc*"
FOUNDRY_PROFILE=dev forge test -vvv --fork-url <RPC_URL>
You can also list tests:
FOUNDRY_PROFILE=dev forge test --list
FOUNDRY_PROFILE=dev forge test --list --json --match-test "testXXX*"
There is an example script in the scripts/foundry
folder. Then you can run:
yarn deploy <FILE_NAME> --rpc-url <NETWORK_NAME>
If you first want to test your deployments/scripts in fork mode. You should run:
source .env
Then fork the network of your choice, by adding the associated script in the package.json
yarn fork:<CHAIN_NAME>
Finnaly run your script in fork mode:
yarn deploy:fork <FILE_NAME>
We recommend the use of this vscode extension.
yarn coverage
You'll need to install lcov brew install lcov
to visualize the coverage report.
yarn gas
To facilitate the interactions with the Diamond Proxy contract on Etherscan, one solution introduced here is to deploy the system with a dummy facet that is in fact a noop mock of the whole diamond.
To get the dummy implementation, solution is to:
- download the repo and follow the instructions
- upload the dummy implementation here
- if the address used has ownership on the Transmuter contracts, run this script to deploy the new dummy facet and add it to the whole Transmuter system
- go to Etherscan and point the
DiamondProxy
to theDiamondEtherscanFacet
contract
Every time a facet is updated with a new function or a change in interface, a new dummy implementation should be deployed and governance should call DiamondEtherscan.setDummyImplementation()
with the newly deployed dummy implementation.
yarn slither
If you're interested in contributing, please see our contributions guidelines.
For any question or feedback you can send an email to [email protected]. Don't hesitate to reach out on Twitter🐦 as well.
The primary license for this repository is the Business Source License 1.1 (BUSL-1.1
). See LICENSE
. Minus the following exceptions:
- Interfaces have a General Public License
- Some libraries have a General Public License
Each of these files states their license type.