The buyTokensUSDC function aggregates a user’s multiple purchases in the same phase into a single record, resulting in a loss of granular transaction details. Subsequent purchases overwrite the purchase timestamp and sum token and USDC amounts, hindering transparency, auditing, and dispute resolution. Moreover, vesting calculations may suffer inaccuracies from relying on aggregated data. This design makes it difficult to track individual events. To mitigate these issues, the contract should store each purchase as a distinct entry—using an array of records per user per phase—preserving unique timestamps and amounts for every transaction, thereby enhancing auditing precision and enabling accurate vesting computations.

The updatePresaleDates function allows the contract owner to modify the presale start and end dates while the presale is active. This means that even in the middle of a sale, the owner can adjust the sale period by providing new start and end timestamps. While this offers flexibility to respond to changing conditions, it also introduces a centralization risk: participants may be impacted by unexpected changes to the sale schedule. Mitigating this risk involves transparent communication with participants and possibly implementing additional governance mechanisms or time locks to restrict arbitrary changes.

This function grants the owner the authority to transfer any ERC20 tokens held by the contract to themselves. It accepts a token address as a parameter, checks the contract’s balance for that token, and if there’s any balance, transfers all of it to the owner. This means the owner could potentially withdraw tokens that were meant for presale participants, including presale tokens, posing a centralization risk. To mitigate this, mechanisms such as restricting withdrawal permissions for presale tokens, implementing time locks, or introducing governance oversight could be considered to ensure fairness and maintain participant trust.

Arbitrary price and sale limit adjustments represent a centralization risk where the owner can unilaterally modify critical sale parameters. In this contract, functions such as setTokenPrice and setTokensaleLimits allow the owner to change the token price and the total tokens allocated for a sale phase at any time. This means the owner could potentially lower the token price to benefit from increased sales or increase the token allocation to manipulate supply, thereby disadvantaging participants. Such flexibility undermines fairness, as buyers might purchase tokens under one set of conditions only for those conditions to be altered later without their consent, potentially leading to market manipulation and loss of investor trust. To mitigate this risk, implementing decentralized governance or multisignature approval for such adjustments is advisable. Time-locks or predetermined, immutable parameters could also be employed, ensuring any changes are transparent and subject to community oversight, thereby protecting participant interests.