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Solidity News Tuesday, March 6 Smart contracts, Trigger code execution, Japan science & more…

Solidity News TLDR / Table of Contents

  • // INSECURE – mapping (address = uint) private userBalances; – – function withdrawBalance() public { – uint amountToWithdraw = userBalances[msg.sender]; – // At this point, the caller’s code is executed, and can call withdrawBalance again – userBalances[msg.sender] = 0; – }HereThe user balance is not set to 0 till we…
  • However, if you cant remove the external call, you should only call the external function after youve finished all the internal work that needs to happen: – mapping (address = uint) private userBalances;function withdrawBalance() public { – uint amountToWithdraw = userBalances[msg.sender]; – userBalances[msg.sender] = 0; // The right place to…
  • Cross-function Race ConditionsAnother potential attack caused by having two functions share the same state – Sharing space (CC Doris Metaf)// INSECURE – mapping (address = uint) private userBalances;function transfer(address to, uint amount) { – if (userBalances[msg.sender] = amount) { – userBalances[to] += amount; – userBalances[msg.sender] -= amount; – } -…
  • The following implementation is insecure: – // INSECURE – mapping (address = uint) private userBalances; – mapping (address = bool) private claimedBonus; – mapping (address = uint) private rewardsForA;function withdraw(address recipient) public { – uint amountToWithdraw = userBalances[recipient]; – rewardsForA[recipient] = 0; – recipient) public { – // Each recipient…
  • Every place you have a call to an external functionyou can decorate with unsafe so in the case above, you can change withdraw() to unsafeWithdraw() that way when calling it, it implies that this function call an unsafe external contractmore about that here.

Tags: smart contracts, trigger code execution, Blockchain smart contracts, numerous smart contracts, unsafe external contract

  • At the heart of its work are the Annual Awards, which recognise the achievements of outstanding staff and volunteers working in prison, probation, and community and youth justice settings.
  • It also works closely with its Award recipients to enable them to develop their work further, as well as helping to spread good practice more widely across the sector.
  • Prospectus is currently looking to recruit an Operations Coordinator on a part-time basis to join the Trust’s small and experienced team.
  • This essential role will be responsible for providing broad office and administrative support to the Director, Operations Manager and various consultants in carrying out the Trust’s work.
  • This person will also be responsible for making travel arrangements and booking accommodation for staff and consultants, helping the book-keeper to record and process finances, and other general office administration tasks.

Tags: part-time basis, Annual Awards, youth justice settings, demonstrable office-based admin, successful candidate

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  • Compile a basic smart contract
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