Under-optimized smart contracts

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Smart Contract Vulnerabilities: As programs running on a blockchain, smart contracts can have security vulnerabilities due to software flaws. For example, one study found that 8,833 of 19,366 Ethereum smart contracts were vulnerable due to factors such as transaction request dependency, timestamp dependency, improper exception handling, and code reentrancy.

When a user interacts with a smart contract in Ethereum, they italy mobile database pay a certain amount of “gas” to do so. Gas and ether (Ethereum’s cryptocurrency) can be exchanged for each other. This creates dead code, opaque predicates, and expensive operations in loops.

Underpriced operations. Ethereum determines its gas price based on execution time, throughput, RAM usage, and other parameters. In general, the gas price is proportional to the computational resources consumed by the operation. However, it is difficult to accurately measure how much resources a particular operation consumes, and therefore some gas price estimates are incorrect. For example, the gas price for some I/O-intensive operations is set too low, allowing a large number of such operations to be executed in a single transaction. This allows an attacker to initiate a DoS attack on Ethereum.