Opyn Protection Process Quality Review

Score : 80%

This is a Process Quality Audit completed on 19 Aug 2020. It was performed using the Process Audit process (version 0.5) and is documented here. The audit was performed by ShinkaRex of Caliburn Consulting. Check out our Telegram.

The final score of the audit is 80%, a great pass. The breakdown of the scoring is in Scoring Appendix.

Summary of the Process

Very simply, the audit looks for the following declarations from the developer's site. With these declarations, it is reasonable to trust the smart contracts.

  1. Here is my smart contract on the blockchain

  2. You can see it matches a software repository used to develop the code

  3. Here is the documentation that explains what my smart contract does

  4. Here are the tests I ran to verify my smart contract

  5. Here are the audit(s) performed to review my code by third party experts

Disclaimer

This report is for informational purposes only and does not constitute investment advice of any kind, nor does it constitute an offer to provide investment advisory or other services. Nothing in this report shall be considered a solicitation or offer to buy or sell any security, future, option or other financial instrument or to offer or provide any investment advice or service to any person in any jurisdiction. Nothing contained in this report constitutes investment advice or offers any opinion with respect to the suitability of any security, and the views expressed in this report should not be taken as advice to buy, sell or hold any security. The information in this report should not be relied upon for the purpose of investing. In preparing the information contained in this report, we have not taken into account the investment needs, objectives and financial circumstances of any particular investor. This information has no regard to the specific investment objectives, financial situation and particular needs of any specific recipient of this information and investments discussed may not be suitable for all investors.

Any views expressed in this report by us were prepared based upon the information available to us at the time such views were written. Changed or additional information could cause such views to change. All information is subject to possible correction. Information may quickly become unreliable for various reasons, including changes in market conditions or economic circumstances.

Executing Code Verification

This section looks at the code deployed on the Mainnet that gets audited and its corresponding software repository. The document explaining these questions is here. This audit will answer the questions;

  1. Is the executing code address(s) readily available? (Y/N)

  2. Is the code actively being used? (%)

  3. Are the Contract(s) Verified/Verifiable? (Y/N)

  4. Does the code match a tagged version in the code hosting platform? (%)

  5. Is the software repository healthy? (%)

Is the executing code address(s) readily available? (Y/N)

Answer: Yes

The contract addresses were quite easy to find. From the Opyn website, I selected Developers from the footer. From the GitBook documentation, the ABI's/Smart Contract Addresses section at the addresses.

They are available at Address 0x39246c4F3F6592C974EBC44F80bA6dC69b817c71 as indicated in the Appendix. This Audit only covers the contract Options Exchange (new). It was deployed 16 May 2020.

Is the code actively being used? (%)

Answer: 70%

Activity is 6.7 transactions a day, as indicated in the Appendix.

Percentage Score Guidance

100% More than 10 transactions a day 70% More than 10 transactions a week 40% More than 10 transactions a month 10% Less than 10 transactions a month 0% No activity

Are the Contract(s) Verified/Verifiable? (Y/N)

Answer: Yes

0x39246c4F3F6592C974EBC44F80bA6dC69b817c71 is the Etherscan verified contract address.

Does the code match a tagged version on a code hosting platform? (%)

Answer: 0%

The Opyn GitHub does not have releases. So, I looked at the branches in order to find a branch that matched the deployed code from May 2020. I was unable to find a branch where the code matched. In every case a variable "payoutTokensReceived" was in the deployed code but not in the repository. There may be a good reason for this, but at this point I have to give a score of 0%.

Guidance:

100% Code matches and Repository was clearly labelled 60 % Code matches but no labelled repository. Repository was found manually 30% Code does match perfectly and repository was found manually 0% Matching Code could not be found

GitHub address : https://github.com/opynfinance/Convexity-Protocol

Deployed contracts in the following file;

Matching Repository: ??

How to improve this score

Ensure there is a clearly labelled repository holding all the contracts, documentation and tests for the deployed code. Ensure an appropriately labeled tag exists corresponding to deployment dates. Release tags are clearly communicated.

Is development software repository healthy? (%)

Answer: 100%

With 344 commits and 39 branches, this is a healthy GitHub.

Documentation

This section looks at the software documentation. The document explaining these questions is here.

Required questions are;

  1. Is there a whitepaper? (Y/N)

  2. Are the basic application requirements documented? (Y/N)

  3. Do the requirements fully (100%) cover the deployed contracts? (%)

  4. Are there sufficiently detailed comments for all functions within the deployed contract code (%)

  5. Is it possible to trace software requirements to the implementation in code (%)

Is there a whitepaper? (Y/N)

Answer: Yes

Location: https://drive.google.com/file/d/1YsrGBUpZoPvFLtcwkEYkxNhogWCU772D/view

Are the basic application requirements documented? (Y/N)

Answer: Yes

Location: https://opyn.gitbook.io/opyn/abis-smart-contract-addresses

Starting with the Protocol Overview, Opyn has very good documentation.

Do the requirements fully (100%) cover the deployed contracts? (%)

Answer: 100%

On my review of the "OptionsExchange: Buy and Sell Options" section of the GitBook, all function were clearly documented with variables, top level explanation and related code, sometimes both Solidity and Web 3

Are there sufficiently detailed comments for all functions within the deployed contract code (%)

Answer: 70

Opyn has a very consistent commenting policy. There is a consistent set of comments before each function with @notice and @param using the NatSpec commenting format. This is used in the generation of the documentation and the ABI json. In addition a line or two in each function for additional explanation of function subtleties . NatSpec is a best practice and with the additional comments and a 38% commenting to code ratio, a score of 70% is given.

Code examples are in the Appendix. As per the SLOC, there is 38% commenting to code.

How to improve this score

This score can improve by adding comments to the deployed code such that it comprehensively covers the code. For guidance, refer to the SecurEth Software Requirements.

Is it possible to trace requirements to the implementation in code (%)

Answer: 100%

Opyn added the function code into the GitBook documentation and included Web 3 code with it. This gives a high level of traceability from the documentation to the code. Exactly what we are looking for.

Guidance: 100% - Clear explicit traceability between code and documentation at a requirement level for all code 60% - Clear association between code and documents via non explicit traceability 40% - Documentation lists all the functions and describes their functions 0% - No connection between documentation and code

Testing

This section looks at the software testing available. It is explained in this document. This section answers the following questions;

  1. Full test suite (Covers all the deployed code) (%)

  2. Code coverage (Covers all the deployed lines of code, or explains misses) (%)

  3. Scripts and instructions to run the tests (Y/N)

  4. Packaged with the deployed code (Y/N)

  5. Report of the results (%)

  6. Formal Verification test done (%)

  7. Stress Testing environment (%)

Is there a Full test suite? (%)

Answer: Yes

With a 347% test to code ratio and a clear set of tests. Though this appear to be more system test than unit tests. By this I mean the tests are organized by actions on the application than by module.

How to improve this score

This score can improve by adding tests to fully cover the code. Document what is covered by traceability or test results in the software repository.

Code coverage (Covers all the deployed lines of code, or explains misses) (%)

Answer: 50%

No documentation I can find indicating code coverage testing or results, but they have a strong test set so 50% score as per rubic below.

Guidance: 100% - Documented full coverage 99-51% - Value of test coverage from documented results 50% - No indication of code coverage but clearly there is a reasonably complete set of tests 30% - Some tests evident but not complete 0% - No test for coverage seen

How to improve this score

This score can improve by adding tests achieving full code coverage. A clear report and scripts in the software repository will guarantee a high score.

Scripts and instructions to run the tests (Y/N)

Answer: Yes

The readme gave all information to execute the test.

Packaged with the deployed code (Y/N)

Answer: Yes

In test directory off of main.

Report of the results (%)

Answer: 0%

No report on coverage or test success is obvious in the mainnet or branches.

How to improve this score

Add a report with the results. The test scripts should generate the report or elements of it.

Formal Verification test done (%)

Answer: 0%

No evidence of Formal Verification found.

Stress Testing environment (%)

Answer: 100%

They advertise test net addresses for both Rinkeby and Kovan. The Options factory contract on Rinkeby is at least still active, as seen in the Appendix.

Audits

Answer: 90%

Single audit reference in their docs (Security section).

Guidance:

  1. Multiple Audits performed before deployment and results public and implemented or not required (100%)

  2. Single audit performed before deployment and results public and implemented or not required (90%)

  3. Audit(s) performed after deployment and no changes required. Audit report is public. (70%)

  4. No audit performed (20%)

  5. Audit Performed after deployment, existence is public, report is not public and no improvements deployed (0%)

Appendices

Author Details

The author of this audit is Rex of Caliburn Consulting.

Email : rex@caliburnc.com Twitter : @ShinkaRex

I started with Ethereum just before the DAO and that was a wonderful education. It showed the importance of code quality. The second Parity hack also showed the importance of good process. Here my aviation background offers some value. Aerospace knows how to make reliable code using quality processes.

I was coaxed to go to EthDenver 2017 and there I started SecuEth.org with Bryant and Roman. We created guidelines on good processes for blockchain code development. We got EthFoundation funding to assist in their development.

Process Quality Audits are an extension of the SecurEth guidelines that will further increase the quality processes in Solidity and Vyper development.

Career wise I am a business development for an avionics supplier.

Scoring Appendix

Executing Code Appendix

Code Used Appendix

Example Code Appendix

/
// File: contracts/OptionsExchange.sol
pragma solidity 0.5.10;
contract OptionsExchange {
uint256 constant LARGE_BLOCK_SIZE = 1651753129000;
uint256 constant LARGE_APPROVAL_NUMBER = 10**30;
UniswapFactoryInterface public UNISWAP_FACTORY;
constructor(address _uniswapFactory) public {
UNISWAP_FACTORY = UniswapFactoryInterface(_uniswapFactory);
}
/*** Events ***/
event SellOTokens(
address seller,
address payable receiver,
address oTokenAddress,
address payoutTokenAddress,
uint256 oTokensToSell,
uint256 payoutTokensReceived
);
event BuyOTokens(
address buyer,
address payable receiver,
address oTokenAddress,
address paymentTokenAddress,
uint256 oTokensToBuy,
uint256 premiumPaid
);
/**
* @notice This function sells oTokens on Uniswap and sends back payoutTokens to the receiver
* @param receiver The address to send the payout tokens back to
* @param oTokenAddress The address of the oToken to sell
* @param payoutTokenAddress The address of the token to receive the premiums in
* @param oTokensToSell The number of oTokens to sell
*/
function sellOTokens(
address payable receiver,
address oTokenAddress,
address payoutTokenAddress,
uint256 oTokensToSell
) public {
// @note: first need to bootstrap the uniswap exchange to get the address.
IERC20 oToken = IERC20(oTokenAddress);
IERC20 payoutToken = IERC20(payoutTokenAddress);
oToken.transferFrom(msg.sender, address(this), oTokensToSell);
uint256 payoutTokensReceived = uniswapSellOToken(
oToken,
payoutToken,
oTokensToSell,
receiver
);
emit SellOTokens(
msg.sender,
receiver,
oTokenAddress,
payoutTokenAddress,
oTokensToSell,
payoutTokensReceived
);
}
/**
* @notice This function buys oTokens on Uniswap and using paymentTokens from the receiver
* @param receiver The address to send the oTokens back to
* @param oTokenAddress The address of the oToken to buy
* @param paymentTokenAddress The address of the token to pay the premiums in
* @param oTokensToBuy The number of oTokens to buy
*/
function buyOTokens(
address payable receiver,
address oTokenAddress,
address paymentTokenAddress,
uint256 oTokensToBuy
) public payable {
IERC20 oToken = IERC20(oTokenAddress);
IERC20 paymentToken = IERC20(paymentTokenAddress);
uniswapBuyOToken(paymentToken, oToken, oTokensToBuy, receiver);
}
/**
* @notice This function calculates the amount of premiums that the seller
* will receive if they sold oTokens on Uniswap
* @param oTokenAddress The address of the oToken to sell
* @param payoutTokenAddress The address of the token to receive the premiums in
* @param oTokensToSell The number of oTokens to sell
*/
function premiumReceived(
address oTokenAddress,
address payoutTokenAddress,
uint256 oTokensToSell
) public view returns (uint256) {
// get the amount of ETH that will be paid out if oTokensToSell is sold.
UniswapExchangeInterface oTokenExchange = getExchange(oTokenAddress);
uint256 ethReceived = oTokenExchange.getTokenToEthInputPrice(
oTokensToSell
);
if (!isETH(IERC20(payoutTokenAddress))) {
// get the amount of payout tokens that will be received if the ethRecieved is sold.
UniswapExchangeInterface payoutExchange = getExchange(
payoutTokenAddress
);
return payoutExchange.getEthToTokenInputPrice(ethReceived);
}
return ethReceived;
}

SLOC Appendix

Solidity Contracts

Language

Files

Lines

Blanks

Comments

Code

Complexity

Solidity

6

1803

216

440

1147

62

Comments to Code 440/ 1147 = 38%

Typescript Tests

Language

Files

Lines

Blanks

Comments

Code

Complexity

TypeScript

12

3991

614

195

3182

55

Tests to Code 3991 / 1147 = 347%

Stress Test Network