This is a Process Quality Audit completed on 11 September 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 63%, a 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.

This completed report is copyright (c) DeFiSafety 2021. Permission is given to copy in whole, retaining this copyright label.

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)

The smart contract addresses were easy to find. Just look for SECURITY on the very long hex.com webpage.

They are available at Address 0x2b591e99afE9f32eAA6214f7B7629768c40Eeb39 as indicated in the Appendix. This Audit only covers the contract _.

How to improve this score

Make the ethereum addresses of the smart contract utilized by your application available on either your website or your github (in the README for instance). Ensure the address is up to date. This is a very important question wrt to the final score.

Is the code actively being used? (%)

Activity is in excess of 200 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)

0x2b591e99afE9f32eAA6214f7B7629768c40Eeb39 is the Etherscan verified contract address.

How to improve this score

Ensure that the deployed code is verified as described in this article for Etherscan or ETHPM. Improving this score may require redeployment.

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

Hex does not have a public GitHub, but a private GitLab. They have listed all the software running on the mainnet on the link of the website. For Hex, Etherscan is a better repo than a software repo. As matching code from the website matches, we give 60% as per the guidance below.

Guidance:

100% All code matches and Repository was clearly labelled 60 % All code matches but no labelled repository. Repository was found manually 30% Almost all code does match perfectly and repository was found manually 0% Most matching Code could not be found

Web address : https://hex.com/techspecs/​

Deployed contracts in the following file;

​

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? (%)

Hex was designed in a private GitLab repo. The author wants it kept private for business reasons (making forking more challenging). In a similar situation to AAVE, there is no healthy repo but strong indications of a private healthy repo. As was done for AAVE, a score of 70% is given.

How to improve this score

Ensure there is a clearly labelled repository holding all the contracts, documentation and tests for the deployed code. Continue to test and perform other verification activities after deployment, including routine maintenance updating to new releases of testing and deployment tools.

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)

While there is not a white paper, per se, the significant description and detail on the main web pages make up for it.

Location: https://hex.com/#header​

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

Location: https://docs.google.com/document/d/1P0ZDaBQx4ghkdX5IUwZb1n8ThvYf7i22MSt9Gm00JRU​

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

In reading the HEX Contract in Layman's terms there is excellent detail in two aspects. It clearly explains all aspects with examples in plain language. Next it lists the majority of contract functions with their arguments and general purpose.

How to improve this score

This score can improve by adding content to the requirements document such that it comprehensively covers the requirements. For guidance, refer to the SecurEth System Description Document . Using tools that aid traceability detection will help.

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

The commenting is high and solid, using NatSpec parameters as well.

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 (%)

In reading the HEX Contract in Layman's terms it clearly documents the functions

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

How to improve this score

This score can improve by adding traceability from requirements to code such that it is clear where each requirement is coded. For reference, check the SecurEth guidelines on traceability.

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? (%)

The biggest disadvantage of the private GitLab is that there are no visible tests, which will drop this section to zero.

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) (%)

No tests visible so score must be 0.

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)

No tests visible so score must be 0.

How to improve this score

Add the scripts to the repository and ensure they work. Ask an outsider to create the environment and run the tests. Improve the scripts and docs based on their feedback.

Packaged with the deployed code (Y/N)

No tests visible so score must be 0.

How to improve this score

Improving this score requires redeployment of the code, with the tests. This score gives credit to those who test their code before deployment and release them together. If a developer adds tests after deployment they can gain full points for all test elements except this one.

Report of the results (%)

No tests visible so score must be 0.

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 (%)

No tests visible so score must be 0.

Stress Testing environment (%)

No tests or test networks visible so score must be 0.

Audits

There are two audits visible, one technical (https://hex.com/docs/HEX-Security-Audit-by-CoinFabrik-DEC2019.pdf), one financial (https://hex.com/docs/HEX%20Economics%20Audit%20by%20CoinFabrik.pdf). This would lead to a 100% score. However, as this audit was done on the AAVE audit, since the audits were done on a private repo, we cannot say for sure the differences between the audited code and the deployed code. For this reason the score is dropped to 75%

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 OR smart contract address' not found, question 1 (0%)

Appendices

Author Details

The author of this audit is Rex of Caliburn Consulting.

Email : rex@defisafety.com Twitter : @defisafety

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 2018 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 manager for an avionics supplier.

Scoring Appendix

Executing Code Appendix

Code Used Appendix

Example Code Appendix

pragma solidity 0.5.10;
​
import "./GlobalsAndUtility.sol";
​
contract StakeableToken is GlobalsAndUtility {
    /**
     * @dev PUBLIC FACING: Open a stake.
     * @param newStakedHearts Number of Hearts to stake
     * @param newStakedDays Number of days to stake
     */
    function startStake(uint256 newStakedHearts, uint256 newStakedDays)
        external
    {
        GlobalsCache memory g;
        GlobalsCache memory gSnapshot;
        _loadGlobals(g, gSnapshot);
​
        /* Enforce the minimum stake time */
        require(newStakedDays >= MIN_STAKE_DAYS, "HEX: newStakedDays lower than minimum");
​
        /* Check if log data needs to be updated */
        _autoStoreDailyDataBefore(g);
​
        _startStake(g, newStakedHearts, newStakedDays, false);
​
        /* Remove staked Hearts from balance of staker */
        _burn(msg.sender, newStakedHearts);
​
        _syncGlobals(g, gSnapshot);
    }
​
    /**
     * @dev PUBLIC FACING: Removes a completed stake from the global pool,
     * distributing the proceeds of any penalty immediately. The staker must
     * still call endStake() to retrieve their stake return (if any).
     * @param stakerAddr Address of staker
     * @param stakeIndex Index of stake within stake list
     * @param stakeIdParam The stake's id
     */
    function goodAccounting(address stakerAddr, uint256 stakeIndex, uint40 stakeIdParam)
        external
    {
        GlobalsCache memory g;
        GlobalsCache memory gSnapshot;
        _loadGlobals(g, gSnapshot);
​
        /* require() is more informative than the default assert() */
        require(staked[stakerAddr].length != 0, "HEX: Empty stake list");
        require(stakeIndex < staked[stakerAddr].length, "HEX: stakeIndex invalid");
​
        StakeStore storage stRef = staked[stakerAddr][stakeIndex];
​
        /* Get stake copy */
        StakeCache memory st;
        _loadStake(stRef, stakeIdParam, st);
​
        /* Stake must have served full term */
        require(g._currentDay >= st._pooledDay + st._stakedDays, "HEX: Stake not fully served");
​
        /* Stake must be in still in global pool */
        require(st._unpooledDay == 0, "HEX: Stake already unpooled");
​
        /* Check if log data needs to be updated */
        _autoStoreDailyDataBefore(g);
​
        /* Remove stake from global pool */
        _unpoolStake(g, st);
​
        /* stakeReturn value is unused here */
        (, uint256 payout, uint256 penalty, uint256 cappedPenalty) = _calcStakeReturn(
            g,
            st,
            st._stakedDays
        );
​
        emit GoodAccounting(
            uint40(block.timestamp),
            stakerAddr,
            stakeIdParam,
            payout,
            penalty,
            msg.sender
        );
​
        if (cappedPenalty != 0) {
            _splitPenaltyProceeds(g, cappedPenalty);
        }
​
        /* st._unpooledDay has changed */
        _updateStake(stRef, st);
​
        _syncGlobals(g, gSnapshot);
    }
​
    /**
     * @dev PUBLIC FACING: Closes a stake. The order of the stake list can change so
     * a stake id is used to reject stale indexes.
     * @param stakeIndex Index of stake within stake list
     * @param stakeIdParam The stake's id
     */
    function endStake(uint256 stakeIndex, uint40 stakeIdParam)
        external
    {
        GlobalsCache memory g;
        GlobalsCache memory gSnapshot;
        _loadGlobals(g, gSnapshot);
​

SLOC Appendix

Solidity Contracts

Comments to Code 47/ 1949 = 38%

​