Big Doge Coin security audit, conducted by the Callisto Network Security Department during July 2021.



Big Doge Coin Security Audit Report

Are Your Funds Safe?


Audit Request

Our main focus is to provide the best entertainment possible for our players on Blockchain. We place key emphasis on creating games that are of a high quality in every way possible. This means that we ensure that all our games themes are engaging, our features unique and captivating and our art, stunning and precise! We don’t cut corners and do whatever is necessary to offer a memorable game-play experience.

Source code

Disclosure policy

Standard disclosure policy.



1. In scope

2. Findings

In total, 1 issue were reported including:

  • 0 high severity issue.
  • 0 medium severity issue.
  • 1 low severity issue.

In total, 9 notes were reported, including:

  • 3 notes.
  • 6 owner privilege.

2.1 Possible incorrect message in require function.

Severity: note.


In the line 466 require(now > _lockTime , "Contract is locked until 7 days"); the message indicates a specific locking period, but function function lock() (line 456) allow to lock to any period.


Replace with message without specific locking period.

2.2 No excluded accounts – unused code.

Severity: note.


The variables in lines 701-702 is declared but never initialized and there are no functions to initialize them.

    mapping (address => bool) private _isExcluded;
    address[] private _excluded;

Therefore contract could not have excluded from rewards addresses, and numbers of functions and its part are unused:

    1. Part of code in function balanceOf (line 791)
    2. Function isExcludedFromReward (lines 825-827)
    3. Part of code in function deliver (line 835)
    4. Part of code in function _takeLiquidity (lines 951-952)
    5. Part of code in function _tokenTransfer (lines 1101-1109)
    6. Function _transferToExcluded (lines 1126-1144)
    7. Function _transferFromExcluded (lines 1136-1144)
    8. Function _transferBothExcluded (lines 860-869)
    9. Part of code in function _getCurrentSupply (lines 938-943).


    To increase readability and reduce deployment cost the unused code should be removed.

    2.3 ERC20 Complines – transfer 0 value should be allowed

    Severity: low.


    Due ERC20 standardTransfers of 0 values MUST be treated as normal transfers and fire the Transfer event.


    Remove require(amount > 0, "Transfer amount must be greater than zero"); (line 1001).

    2.4 Unused variable mintedByDxsale

    Severity: note.


    The variable mintedByDxsale (line 708) was declared but never used.


    To increase readability and reduce deployment cost the unused code should be removed.

    2.5 Owner privileges

    Severity: owner privileges.


    Contract owner has right to:

    1. Exclude/include any account from/in fee, using functions excludeFromFee (lines 871-873) and includeInFee (lines 875-877).
    2. Change tax fee in range from 0 to maxTaxFee percent, using function setTaxFeePercent (lines 879-878).
    3. Change liquidity fee in range from 0 to maxLiqFee percent, using function setLiquidityFeePercent (lines 884-887).
    4. Change maximal amount per transaction in range from minMxTxPercentage to 100 percent of total supply, using function setMaxTxPercent (lines 889-894).
    5. Enable or disable adding liquidity to pool, using function setSwapAndLiquifyEnabled (lines 896-899).
    6. Enable or disable all fees and transaction amount limit, using functions disableFees (lines 1146-1154) and enableFees (lines 1156-1161).

    3. Security practice

    •  Open-source contact.
    •  The contract should pass a bug bounty after the completion of the security audit.
    •  Public testing.
    •  Automated anomaly detection systems. – NOT IMPLEMENTED. A simple anomaly detection algorithm is recommended to be implemented to detect behavior that is atypical compared to normal for this contract. For instance, the contract must halt deposits in case a large amount is being withdrawn in a short period of time until the owner or the community of the contract approves further operations.
    •  Multisig owner account.
    •  Standard ERC20-related issues. – NOT IMPLEMENTED. It is known that every contract can potentially receive an unintended ERC20-token deposit without the ability to reject it even if the contract is not intended to receive or hold tokens. As a result, it is recommended to implement a function that will allow extracting any arbitrary number of tokens from the contract.
    •  Crosschain address collisions. ETH, ETC, CLO, etc. It is possible that a transaction can be sent to the address of your contract at another chain (as a result of a user mistake or some software fault). It is recommended that you deploy a “mock contract” that would allow you to withdraw any tokens from that address or prevent any funds deposits. Note that you can reject transactions of native token deposited, but you can not reject the deposits of ERC20 tokens. You can use this source code as a mock contract: extractor contract source code. The address of a new contract deployed using CREATE (0xf0) opcode is assigned following this scheme keccak256(rlp([sender, nonce])). Therefore you need to use the same address that was originally used at the main chain to deploy the mock contract at a transaction with the nonce that matches that on the original chain. Example: If you have deployed your main contract with address 0x010101 at your 2021th transaction then you need to increase your nonce of 0x010101 address to 2020 at the chain where your mock contract will be deployed. Then you can deploy your mock contract with your 2021th transaction, and it will receive the same address as your mainnet contract.

4. Conclusion

The audited smart contract can be deployed. Only low severity issues were found during the audit.

It is recommended to adhere to the security practices described in pt. 4 of this report to ensure the contract’s operability and prevent any issues that are not directly related to the code of this smart contract.


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