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Curve Finance

93%

Previous versions

Process Quality Review (0.8)

Curve Finance

Final score:93%
Date:31 Jan 2022
Audit Process:version 0.8
Author:Nick
PQR Score:93%

PASS

Protocol Website:

Scoring Appendix

The final review score is indicated as a percentage. The percentage is calculated as Achieved Points due to MAX Possible Points. For each element the answer can be either Yes/No or a percentage. For a detailed breakdown of the individual weights of each question, please consult this document.

The blockchain used by this protocol
Ethereum
#QuestionAnswer
100%
1.100%
2.100%
3.Yes
4.100%
5.100
94%
6.Yes
7.Yes
8.100%
9.60%
72%
10.100%
11.60%
12.Yes
13.0%
14.No
15.Yes
95%
16.100%
17.60%
97%
18.100%
19.100%
20.100%
21.100%
22.100%
23.80%
24.100%
25.100%
100%
26.100%
27.Yes
28.Yes
Total:93%

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.

  • Here is my smart contract on the blockchain
  • You can see it matches a software repository used to develop the code
  • Here is the documentation that explains what my smart contract does
  • Here are the tests I ran to verify my smart contract
  • Here are the audit(s) performed to review my code by third party experts

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, token, 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. The views expressed within this report are limited to DeFiSafety and the author and do not reflect those of any additional or third party and are strictly based upon DeFiSafety, its authors, interpretations and evaluation of relevant data. 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.

Smart Contracts & Team

100%

This section looks at the code deployed on the relevant chain that gets reviewed and its corresponding software repository. The document explaining these questions is here.

1. Are the smart contract addresses easy to find?(%)

Answer: 100%

Smart contracts are easily located.

Percentage Score Guidance:
100%
Clearly labelled and on website, documents or repository, quick to find
70%
Clearly labelled and on website, docs or repo but takes a bit of looking
40%
Addresses in mainnet.json, in discord or sub graph, etc
20%
Address found but labeling not clear or easy to find
0%
Executing addresses could not be found

2. How active is the primary contract? (%)

Answer: 100%

Primary contracts are very active, with some stable swaps being used 20 or 30 times a day.

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

3. Does the protocol have a public software repository? (Y/N)

Answer: Yes

Curve uses GitHub as a software repository.

Score Guidance:
Yes
There is a public software repository with the code at a minimum, but also normally test and scripts. Even if the repository was created just to hold the files and has just 1 transaction.
No
For teams with private repositories.

4. Is there a development history visible? (%)

Answer: 100%

At 898 commits, this repo is almost as endless as Curve's logo.

Percentage Score Guidance:
100%
Any one of 100+ commits, 10+branches
70%
Any one of 70+ commits, 7+branches
50%
Any one of 50+ commits, 5+branches
30%
Any one of 30+ commits, 3+branches
0%
Less than 2 branches or less than 30 commits

5. Is the team public (not anonymous)? (Y/N)

Answer: 100

Two team members are public and they self-report working for Curve. One of the founders, Michael Egorov, can also be found at https://www.linkedin.com/in/michael-egorov/.

Score Guidance:
100%
At least two names can be easily found in the protocol's website, documentation or medium. These are then confirmed by the personal websites of the individuals / their linkedin / twitter.
50%
At least one public name can be found to be working on the protocol.
0%
No public team members could be found.

Documentation

94%

The difference between this and the old link is solely the link.    This section looks at the software documentation. The document explaining these questions is here.

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

Answer: Yes

Curve has multiple whitepapers, though the most user accessible is their Gitbook.

7. Is the protocol's software architecture documented? (Y/N)

Answer: Yes

Curve's software architecture is well documented using specific references to contracts.

Score Guidance:
Yes
The documents identify software architecture and contract interaction through any of the following: diagrams, arrows, specific reference to software functions or a written explanation on how smart contracts interact.
No
Protocols receive a "no" if none of these are included.

8. Does the software documentation fully cover the deployed contracts' source code? (%)

Answer: 100%

The software function documentation covers all contracts deployed.

Percentage Score Guidance:
100%
All contracts and functions documented
80%
Only the major functions documented
79 - 1%
Estimate of the level of software documentation
0%
No software documentation

9. Is it possible to trace the documented software to its implementation in the protocol's source code? (%)

Answer: 60%

There is strong association between code and documents, but there is no explicit traceability.

Percentage Score 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

72%

10. Has the protocol tested their deployed code? (%)

Answer: 100%

Due to our testing tool not being optimized for vyper files, we had to rely on other methods to get an accurate measure of the depth of Curve's testing. Thankfully, they have provided proof of extensive and all-encompassing testing through our Twitter thread with them.

Percentage Score Guidance:
100%
TtC > 120% Both unit and system test visible
80%
TtC > 80% Both unit and system test visible
40%
TtC < 80% Some tests visible
0%
No tests obvious

11. How covered is the protocol's code? (%)

Answer: 60%

Although the protocol offers a code coverage report for users running their own tests, there are no results. . However, with clear in-depth testing practices, Curve gets a 60% for this question.

Percentage Score 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 complete set of tests
30%
Some tests evident but not complete
0%
No test for coverage seen

12. Does the protocol provide scripts and instructions to run their tests? (Y/N)

Answer: Yes

Curve provides scripts.

Score Guidance:
Yes
Scripts and/or instructions to run tests are available in the testing suite
No
Scripts and/or instructions to run tests are not available in the testing suite

13. Is there a detailed report of the protocol's test results?(%)

Answer: 0%

No test report is evident.

Percentage Score Guidance:
100%
Detailed test report as described below
70%
GitHub code coverage report visible
0%
No test report evident

14. Has the protocol undergone Formal Verification? (Y/N)

Answer: No

Curve has not undergone formal verification.

Score Guidance:
Yes
Formal Verification was performed and the report is readily available
No
Formal Verification was not performed and/or the report is not readily available.

15. Were the smart contracts deployed to a testnet? (Y/N)

Answer: Yes

Curve uses testnets with their various deployments to new networks.

Score Guidance:
Yes
Protocol has proved their tesnet usage by providing the addresses
No
Protocol has not proved their testnet usage by providing the addresses

Security

95%

This section looks at the 3rd party software audits done. It is explained in this document.

16. Is the protocol sufficiently audited? (%)

Answer: 100%

Curve has been audited three times, two of which were pre-launch.

Percentage Score Guidance:
100%
Multiple Audits performed before deployment and the audit findings are public and implemented or not required
90%
Single audit performed before deployment and audit findings are public and implemented or not required
70%
Audit(s) performed after deployment and no changes required. The Audit report is public.
65%
Code is forked from an already audited protocol and a changelog is provided explaining why forked code was used and what changes were made. This changelog must justify why the changes made do not affect the audit.
50%
Audit(s) performed after deployment and changes are needed but not implemented.
30%
Audit(s) performed are low-quality and do not indicate proper due diligence.
20%
No audit performed
0%
Audit Performed after deployment, existence is public, report is not public OR smart contract address' not found.
Deduct 25% if the audited code is not available for comparison.

17. Is the bounty value acceptably high (%)

Answer: 60%

Curve offers $250K with a static program.

Percentage Score Guidance:
100%
Bounty is 10% TVL or at least $1M AND active program (see below)
90%
Bounty is 5% TVL or at least 500k AND active program
80%
Bounty is 5% TVL or at least 500k
70%
Bounty is 100k or over AND active program
60%
Bounty is 100k or over
50%
Bounty is 50k or over AND active program
40%
Bounty is 50k or over
20%
Bug bounty program bounty is less than 50k
0%
No bug bounty program offered / the bug bounty program is dead
An active program means that a third party (such as Immunefi) is actively driving hackers to the site. An inactive program would be static mentions on the docs.

Admin Controls

97%

This section covers the documentation of special access controls for a DeFi protocol. The admin access controls are the contracts that allow updating contracts or coefficients in the protocol. Since these contracts can allow the protocol admins to "change the rules", complete disclosure of capabilities is vital for user's transparency. It is explained in this document.

18. Is the protocol's admin control information easy to find?

Answer: 100%

Admin controls are easy to find. However, they need updating so that users can find them all in one location with sufficient detail yet still in straightforward language.

Percentage Score Guidance:
100%
Admin Controls are clearly labelled and on website, docs or repo, quick to find
70%
Admin Controls are clearly labelled and on website, docs or repo but takes a bit of looking
40%
Admin Control docs are in multiple places and not well labelled
20%
Admin Control docs are in multiple places and not labelled
0%
Admin Control information could not be found

19. Are relevant contracts clearly labelled as upgradeable or immutable? (%)

Answer: 100%

Relevant contracts are clearly labelled as upgradeable or immutable in the various sections of their technical documentation.

Percentage Score Guidance:
100%
Both the contract documentation and the smart contract code state that the code is not upgradeable or immutable.
80%
All Contracts are clearly labelled as upgradeable (or not)
50%
Code is immutable but not mentioned anywhere in the documentation
0%
Admin control information could not be found

20. Is the type of smart contract ownership clearly indicated? (%)

Answer: 100%

Ownership is in the hands of the DAO, as stated.

Percentage Score Guidance:
100%
The type of ownership is clearly indicated in their documentation. (OnlyOwner / MultiSig / etc)
50%
The type of ownership is indicated, but only in the code. (OnlyOwner / MultiSig / etc)
0%
Admin Control information could not be found

21. Are the protocol's smart contract change capabilities described? (%)

Answer: 100%

Contracts that are capable of change (or not) are identified.

Percentage Score Guidance:
100%
The documentation covers the capabilities for change for all smart contracts
50%
The documentation covers the capabilities for change in some, but not all contracts
0%
The documentation does not cover the capabilities for change in any contract

22. Is the protocol's admin control information easy to understand? (%)

Answer: 100%

Information regarding admin control and its relation to user funds' safety is clearly described at https://resources.curve.fi/faq/security.

Percentage Score Guidance:
100%
All the contracts are immutable
90%
Description relates to investments safety in clear non-software language
30%
Description all in software-specific language
0%
No admin control information could be found

23. Is there sufficient Pause Control documentation? (%)

Answer: 80%

An in-depth mention of a their pause control is documented here.

Percentage Score Guidance:
100%
Pause control(s) are clearly documented and there is records of at least one test within 3 months
80%
Pause control(s) explained clearly but no evidence of regular tests
40%
Pause controls mentioned with no detail on capability or tests
0%
Pause control not documented or explained

24. Is there sufficient Timelock documentation? (%)

Answer: 100%

No timelock documentation is detailed. However, their DAO structure fundamentally operates like a timelock due to admin's giving up ownership to the DAO, and every vote on contract changes has to go through a lengthy voting process. In addition, Curve has clearly stated that the only contract that the DAO does not have full ownership of is the CRV DAO token. Regardless, the token contract restricts all admin access and external call possibilities. This renders the need for a timelock effectively useless for any Curve contract.

Percentage Score Guidance:
100%
Documentation identifies and explains why the protocol does not need a Timelock OR Timelock documentation identifies its duration, which contracts it applies to and justifies this time period.
60%
A Timelock is identified and its duration is specified
30%
A Timelock is identified
0%
No Timelock information was documented

25. Is the Timelock of an adequate length? (Y/N)

Answer: 100%

The voting of the DAO acting as a timelock, its length is parallel to the overall voting process which takes 10 days.

Percentage Score Guidance:
100%
Timelock is between 48 hours to 1 week OR justification as to why no Timelock is needed / is outside this length.
50%
Timelock is less than 48 hours or greater than 1 week.
0%
No Timelock information was documented OR no timelock length was identified.

Oracles

100%

This section goes over the documentation that a protocol may or may not supply about their Oracle usage. Oracles are a fundamental part of DeFi as they are responsible for relaying tons of price data information to thousands of protocols using blockchain technology. Not only are they important for price feeds, but they are also an essential component of transaction verification and security. This is explained in this document.

26. Is the protocol's Oracle sufficiently documented? (%)

Answer: 100%

Curve uses TWAP oracles.

Percentage Score Guidance:
100%
If it uses one, the Oracle is specified. The contracts dependent on the oracle are identified. Basic software functions are identified (if the protocol provides its own price feed data). Timeframe of price feeds are identified. OR The reason as to why the protocol does not use an Oracle is identified and explained.
75%
The Oracle documentation identifies both source and timeframe, but does not provide additional context regarding smart contracts.
50%
Only the Oracle source is identified.
0%
No oracle is named / no oracle information is documented.

27. Is front running mitigated by this protocol? (Y/N)

Answer: Yes

Curve details front-running mitigation in their docs.

Score Guidance:
Yes
The protocol cannot be front run and there is an explanation as to why OR documented front running countermeasures are implemented.
No
The Oracle documentation identifies both source and timeframe, but does not provide additional context regarding smart contracts.

28. Can flashloan attacks be applied to the protocol, and if so, are those flashloan attack risks mitigated? (Y/N)

Answer: Yes

Flashloan countermeasures are implemented.

Score Guidance:
Yes
The protocol's documentation includes information on how they mitigate the possibilities and extents of flash loan attacks.
No
The protocol's documentation does not include any information regarding the mitigation of flash loan attacks.

Appendices

1# Events
2event TokenExchange:
3    buyer: indexed(address)
4    sold_id: int128
5    tokens_sold: uint256
6    bought_id: int128
7    tokens_bought: uint256
8
9
10event AddLiquidity:
11    provider: indexed(address)
12    token_amounts: uint256[N_COINS]
13    fees: uint256[N_COINS]
14    invariant: uint256
15    token_supply: uint256
16
17event RemoveLiquidity:
18    provider: indexed(address)
19    token_amounts: uint256[N_COINS]
20    fees: uint256[N_COINS]
21    token_supply: uint256
22
23event RemoveLiquidityOne:
24    provider: indexed(address)
25    token_amount: uint256
26    coin_amount: uint256
27
28event RemoveLiquidityImbalance:
29    provider: indexed(address)
30    token_amounts: uint256[N_COINS]
31    fees: uint256[N_COINS]
32    invariant: uint256
33    token_supply: uint256
34
35event CommitNewAdmin:
36    deadline: indexed(uint256)
37    admin: indexed(address)
38
39event NewAdmin:
40    admin: indexed(address)
41
42
43event CommitNewFee:
44    deadline: indexed(uint256)
45    fee: uint256
46    admin_fee: uint256
47
48event NewFee:
49    fee: uint256
50    admin_fee: uint256
51
52event RampA:
53    old_A: uint256
54    new_A: uint256
55    initial_time: uint256
56    future_time: uint256
57
58event StopRampA:
59    A: uint256
60    t: uint256
61
62
63# This can (and needs to) be changed at compile time
64N_COINS: constant(int128) = 3  # <- change
65
66FEE_DENOMINATOR: constant(uint256) = 10 ** 10
67LENDING_PRECISION: constant(uint256) = 10 ** 18
68PRECISION: constant(uint256) = 10 ** 18  # The precision to convert to
69PRECISION_MUL: constant(uint256[N_COINS]) = [1, 1000000000000, 1000000000000]
70RATES: constant(uint256[N_COINS]) = [1000000000000000000, 1000000000000000000000000000000, 1000000000000000000000000000000]
71FEE_INDEX: constant(int128) = 2  # Which coin may potentially have fees (USDT)
72
73MAX_ADMIN_FEE: constant(uint256) = 10 * 10 ** 9
74MAX_FEE: constant(uint256) = 5 * 10 ** 9
75MAX_A: constant(uint256) = 10 ** 6
76MAX_A_CHANGE: constant(uint256) = 10
77
78ADMIN_ACTIONS_DELAY: constant(uint256) = 3 * 86400
79MIN_RAMP_TIME: constant(uint256) = 86400
80
81coins: public(address[N_COINS])
82balances: public(uint256[N_COINS])
83fee: public(uint256)  # fee * 1e10
84admin_fee: public(uint256)  # admin_fee * 1e10
85
86owner: public(address)
87token: CurveToken
88
89initial_A: public(uint256)
90future_A: public(uint256)
91initial_A_time: public(uint256)
92future_A_time: public(uint256)
93
94admin_actions_deadline: public(uint256)
95transfer_ownership_deadline: public(uint256)
96future_fee: public(uint256)
97future_admin_fee: public(uint256)
98future_owner: public(address)
99
100is_killed: bool
101kill_deadline: uint256
102KILL_DEADLINE_DT: constant(uint256) = 2 * 30 * 86400
103
104
105@external
106def __init__(
107    _owner: address,
108    _coins: address[N_COINS],
109    _pool_token: address,
110    _A: uint256,
111    _fee: uint256,
112    _admin_fee: uint256
113):
114    """
115    @notice Contract constructor
116    @param _owner Contract owner address
117    @param _coins Addresses of ERC20 conracts of coins
118    @param _pool_token Address of the token representing LP share
119    @param _A Amplification coefficient multiplied by n * (n - 1)
120    @param _fee Fee to charge for exchanges
121    @param _admin_fee Admin fee
122    """
123    for i in range(N_COINS):
124        assert _coins[i] != ZERO_ADDRESS
125    self.coins = _coins
126    self.initial_A = _A
127    self.future_A = _A
128    self.fee = _fee
129    self.admin_fee = _admin_fee
130    self.owner = _owner
131    self.kill_deadline = block.timestamp + KILL_DEADLINE_DT
132    self.token = CurveToken(_pool_token)
133
134
135@view
136@internal
137def _A() -> uint256:
138    """
139    Handle ramping A up or down
140    """
141    t1: uint256 = self.future_A_time
142    A1: uint256 = self.future_A
143
144    if block.timestamp < t1:
145        A0: uint256 = self.initial_A
146        t0: uint256 = self.initial_A_time
147        # Expressions in uint256 cannot have negative numbers, thus "if"
148        if A1 > A0:
149            return A0 + (A1 - A0) * (block.timestamp - t0) / (t1 - t0)
150        else:
151            return A0 - (A0 - A1) * (block.timestamp - t0) / (t1 - t0)
152
153    else:  # when t1 == 0 or block.timestamp >= t1
154        return A1
155

JavaScript Tests

Language
Files
Lines
Blanks
Comments
Testing Code
Deployed Code
Complexity
Python
51
4389
997
313
3079
30196
641

Tests to Code: 3079 / 30196 = 10 %