Hack The Chain

Smart Contract Security Challenges

Find and solve vulnerabilities in real-world smart contract scenarios.

Transient Storage
Easy Solidity

Transient Storage

This exercise demonstrates a vulnerability in reentrancy protection. The SimpleBank contract allows users to deposit and withdraw funds, but its nonReentrant modifier contains an obvious flaw.

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Variable Modification
Easy Solidity

Variable Modification

A simple exercise to learn how to modify state variables in a smart contract.

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