This article talks about ways you can protect NFT smart contracts from hackers. The goal of a hacker is almost always to get access to your funds inside your crypto wallet. Before we start giving you security advice, lets recap what a smart contract actually is. Smart contracts are computer programs that are uploaded to the Ethereum blockchain (click here to see our article on smart contract development). Once on the blockchain, people can then interact with it when certain conditions have been met. The coding of the smart contract determines who is allowed to interact with it. Blockchain and smart contract technology is still quite new, which means advice to keep your contracts safe is rare at the moment. Protecting your smart contract from hackers is essential. Unfortunately, most people who crate or invest in NFTs do not know much about the technology behind them. If creators do not know anything about the technology, then it means their assets are vulnerable to attack. We have researched the best ways to keep your smart contract safe as possible.
Top Smart Contract Security Tips
Test Your Code
Test your smart contract before deploying it. If you are planning to use Opensea, then you can create a test account on Opensea by visiting the Opensea Testnets website. To use Opensea Testnets you must login using a test network such as Rinkerby, Kovan or Ropsten. These testnets similar the blockchain very well, because they are actually on a blockchain! You will also need to fund these accounts with Rinkerby, Kovan or Ropsten crypto currency which you can get for free from particular websites. When testing you contract you want to make sure transactions work as they should. Even test using a different wallet account. You also want to test that your meta data is being displayed on Opensea, if your smart contract is for digital objects like art.
Use an Easy Coding Language
The best way to program a smart contract is to use a blockchains own programming language. For example, Solidity is the programming language invented especially for the Ethereum blockchain.
Make the Code Simple as Possible
When coding in general, it is always best to try and keep things simple. Always remember that longer and complex code introduces more variables that could go wrong, or be hacked.
Incorporate a Fail Safe Mechanisms. For example, you could put in some code that will slow down unusual behaviour. This is called a speed bump, which helps to give the admin more time to correct the issue. Or you could have a rate limit on particular functions being called, encase the hacker is trying to use a bot to repeatably attack certain parts of your contract.
Design Secure Access
Your contract should be designed so that only the admin has the right to change the most important things. Ensure that there is multi level security measures when giving people access to certain functions.
Get a security audit done. Slither is a static analysis framework (written in Python 3), that can be used to test for bugs and security issues in smart contracts. The Solidity compiler produces Solidity AST from the source code, which is used as input for Slither.
Use Vulnerability Scanners
Automated Vulnerability Scanners can be used to automatically scan your smart contract for any obvious security issues. It can help you identify bugs in the code that can lead to security vulnerabilities.
Smart Contract Audit Tools
The SWC Registry is a website which contains data regarding smart contract weakness and vulnerabilities. The data is in the form of tables.
MythX is a smart contract security service for the Ethereum blockchain. This website is also integrated with developer tools, and outputs detailed analysis reports regarding security vulnerabilities.
Oyente is an open-source security analysis tool for smart contracts.
SmartCheck is an excellent static analysis tool to help identify Ethereum smart contract vunerabilities and other coding issues.
Octopus Deploy is a security analysis framework for smart contracts.
Smart contracts Best Practices
- Always make it clear to the user (and yourself!) what your smart contract does.
- The best way to understand your contract is to create a visual diagram of how it works. You can do this by creating something called a slither print. This basically prints a contracts information in the form of a logical diagram.
- If using Solidity, we recommend you do thorough code documentation using Ethereum Natural Language Specification Format (Natspec format).
The Bottom Line
We hope you have found this article on How To Protect NFT Smart Contracts from Hackers informative. Please write to us if you think we need to add anything more to this article. Our goal is to keep people safe as possible.