Mastering Ethereum

Chapter 8. Smart Contracts and Vyper

Vyper is an experimental, contract-oriented programming language for the Ethereum Virtual Machine that strives to provide superior auditability, by making it easier for developers to produce intelligible code. In fact, one of the principles of Vyper is to make it virtually impossible for developers to write misleading code.

In this chapter we will look at common problems with smart contracts, introduce the Vyper contract programming language, and compare it to Solidity, demonstrating the differences.

Vulnerabilities and Vyper

A recent study analyzed nearly one million deployed Ethereum smart contracts and found that many of these contracts contained serious vulnerabilities. During their analysis, the researchers outlined three basic categories of trace vulnerabilities:

Suicidal contracts

Smart contracts that can be killed by arbitrary addresses

Greedy contracts

Smart contracts that can reach a state in which they cannot release ether

Prodigal contracts

Smart contracts that can be made to release ether to arbitrary addresses

Vulnerabilities are introduced into smart contracts via code. It may be strongly argued that these and other vulnerabilities are not intentionally introduced, but regardless, undesirable smart contract code evidently results in the unexpected loss of funds for Ethereum users, and this is not ideal. Vyper is designed to make it easier to write secure code, or equally to make it more difficult to accidentally write ...