📖
Web3 Encyclopedia
  • Welcome aboard!
  • Source
  • 😀Evolution from Web 1.0 to Web 3.0
    • Web 1.0 Web 2.0 Web 3.0
    • Key Features
    • Current Limitations
    • Future of Web 3.0
    • Learn: What Is Web3?
    • Learn: Will Every Brand Have a Web3 Strategy?
    • Learn: Big Ideas in 2023
    • Learn: The Web3 Paradox: Why Scaling Usage Alone Won't Lead to Mass Adoption?
    • Learn: Is Web3 A Marketing Buzz or Tech Revolution?
    • Learn: What is the relationship between blockchain and Web3?
    • Learn:Empowering Women in Web 3.0: The Role and Contributions of Women in Blockchain, DeFi, and dApp
    • Learn: Web 3.0 and the Future of E-Commerce
    • Learn: 12 ways ecosystem projects can attract more developers
    • Learn: How Web3 is Impacting Education?
    • Learn: Web3 And The Future Of Digital Advertising
    • Learn: Web3’s impact on personalization, trust and engagement
    • Learn: Web3-Powered Identity Management -- Unlocking the Benefits of Decentralization
    • Learn: Why Web2 companies fail in Web3 while others made it?
    • Learn: To Identify or Not in a Web3 World?
    • 🤫[Insider Series] McKinsey x Web3
    • TL;DR 👀
  • 💲Blockchain Fundamentals
    • Why is Blockchain So Popular?
    • Introduction to Blockchain
    • Blockchain Misconceptions
    • Blockchain vs Bitcoin, Database, Cloud
    • Consensus Mechanism
    • Public and Private Keys
    • Hash Functions and Cryptography
    • Sharding
    • Types of Blockchains: PoW, PoS and Private
    • Understanding Cryptocurrency
    • Coins vs Tokens
    • Blockchain Trilemma
    • Legality
    • Learn : Google’s Cloud Based Blockchain Node Service
    • Learn: How Blockchain, Digital assets, and Web3 Unlock Financial Inclusion Globally
    • Learn: Will Chinese-Made Crypto Soar Higher?
    • Learn: What Does MiCA Mean for Crypto in Europe?
    • Learn: Unraveling the Intricacies of Blockchain Forensics and Asset Tracking
    • Learn: Promising blockchain use cases in healthcare industry
    • Learn: The Role of Blockchain in Authenticating and Provenance Art
    • Learn: Blockchain-Based Digital Identity: Benefits, Risks, and Implementation Challenges
    • Learn: The Future of Energy Supply Chains
    • Learn: Revolutionizing smart contracts and cryptocurrency
    • Learn: Nigeria goes blockchain
    • Learn: A Game Changer for Online Gaming?
    • Learn: Is blockchain technology ready for high-storage applications?
    • Learn: Will Blockchain Technology Mark a Turning Point in Fraud Prevention?
    • Learn: Why ZK-rollups need data availability?
    • Learn: How will generative AI disrupt blockchain?
    • Learn: A New Blockchain for Generative AI?
    • TL;DR 👀
  • 🏟️Web3 Utilities
    • Decentralized Applications (dApps)
    • Cross-chain Bridges
    • DAO
    • Artificial Intelligence
    • Learn: Is Community-building Essential for Web3 Startups?
    • Learn: ‘Decentralization Theater’
    • Learn: Crypto and AI- A yay or nay combination?
    • Learn: Dissecting the DAO
    • Learn: What is motivating Lido DAO to rise?
    • Learn: How to Turn Your Community Into a DAO?
    • Learn: The Key to Decentralized Decision Making
    • Learn: How Web 3.0 can disrupt the supply chain industry?
    • TL;DR 👀
  • 🪙Bitcoin
    • What is Bitcoin
    • Bitcoin's Blockchain Technology
    • UTXO Model and Transaction Fees
    • Bitcoin Mining and Mempool
    • Learn: What is bitcoin mining?
    • What are Hard Forks and Soft Forks
    • What is SegWit and the Lightning Network
    • Bitcoin Ecosystem
    • Can Bitcoin be Destroyed? Game Theory and Network Attacks
    • Learn: Crypto token supplies explained
    • Learn: What is crypto tax-loss harvesting, and how does it work?
    • Learn: Can Crypto Go Green? How to Invest in Eco-Friendly Cryptocurrencies
    • Learn: Why Did FTX Collapse? Here’s What to Know.
    • Learn: How Sam Bankman-Fried swindled $8 billion in customer money?
    • Learn: How much is Bitcoin worth today?
    • Learn: The Costs of Running a Bitcoin Node In Nigeria
    • Learn: Has 2022 Left Any Crypto Positives?
    • Learn: How Crypto Exchanges Can Be Free of Risk?
    • Learn: Greed, Lies and FTX: Is Crypto a Force for Good or Evil?
    • Learn: Is Crypto a Cultural Movement?
    • Learn: What are the consequences of crypto’s ongoing regulatory process?
    • Learn: Beyond the Crash and Embracing NFTs?
    • Learn: Understanding crypto bag holders and their mindset
    • Learn: Inscriptions: Just A Fad, Or A Real Threat To Bitcoin Becoming Decentralized Money?
    • Learn: How Bitcoin Ordinals Can Change the Future Of Mining?
    • Learn: What is a supernet?
    • Learn: Bitcoin Miners Celebrate 10 Years Since First ASIC, What Changed Since Then?
    • Learn: Bill Vs. CBDC – Why This US Congressman Wants To Block The Fed From Issuing A Digital Dollar?
    • Learn: Why Bitcoin Will Blow People’s Minds In 2025?
    • Learn: How the Howey Test Sheds Light on Cryptocurrency's Regulatory Gray Area
    • Learn: Cryptocurrency vs AI: A Complex Debate
    • Learn: Where the U.S. Government Went Wrong in Regulating Crypto?
    • Learn: The Nostr Privacy Paradox
    • Learn: Do algorithmic stablecoins have a future as centralized coins are under scrutiny?
    • Learn: Is Bitcoin Set To Revolutionize The Financial World With Its Superior Purchasing Power?
    • Learn: What is Shibarium, and what does it mean for Shiba Inu?
    • Learn: What is a crypto dusting attack?
    • Learn: Is the Adoption of Central Bank Digital Currencies (CBDCs) the Future?
    • Learn: How Artificial Intelligence Could Revolutionize Crypto?
    • Learn: What’s next for EU’s crypto industry as European Parliament passes MiCA?
    • Learn: Why the EU Has MiCA and the U.S. Has Securities Law Confusion?
    • Learn: Six New Projects Looking to Mitigate Bitcoin Mining’s Energy Footprint
    • Learn: Who on Crypto Twitter chose not to pay for a blue checkmark?
    • Learn: What is the wash-sale rule in Crypto?
    • Learn: What is Pepecoin and can it flip memecoins Dogecoin and Shiba Inu?
    • Learn: Can you recover stolen Bitcoin from crypto scams?
    • Learn: What the ‘anti-mining bill’ means for the crypto industry in Texas?
    • Learn: Does the US have a crypto ‘tax loophole’ problem?
    • Learn: How users can stay protected?
    • Learn: How Crypto Revolutionize Cheaper and Faster Transactions?
    • Learn: Can NFTs and CFDs be BFFs?
    • Learn: A PR expert’s tips for memecoin projects
    • Learn: Why politicians aren't convinced about the Digital Euro?
    • Learn: How A 90-Year Old TA Theory Predicted The Sudden Bitcoin Boom?
    • Learn: Social Trading Platforms and CFDs: A New Paradigm in Investment
    • Learn: How could the Chinese economic crisis impact Bitcoin and crypto?
    • Learn: How do they compare: Bitcoin IRA vs. traditional IRA?
    • Learn: Why Tokenized Assets Are Safer During a Banking Crisis?
    • TL;DR 👀
  • 🛢️Ethereum
    • Bitcoin vs Ethereum
    • What can Ethereum do?
    • What is Ether (ETH)?
    • What's Unique About ETH?
    • What are Smart Contracts?
    • Energy Consumption?
    • Ethereum Virtual Machine (EVM)
    • Pros & Cons of Smart Contracts
    • Decentralized Applications (dApps)
    • Ethereum Token Standards (ERC-20, ERC-721 and ERC-1155)
    • Evolution of Ethereum
    • How to Get Your First Ethereum
    • Learn: Next Ethereum Upgrade — Shanghai Upgrade
    • Learn: Tipping Scale for Crypto Adoption: Usability vs. Accessibility
    • Learn: Major Publicly Traded U.S. Bitcoin Miner Files For Chapter 11 – Impact On The Market?
    • Learn: 5 altcoin projects that made a real difference in 2022
    • Learn: How Tether Can Be a More Stable Stablecoin?
    • Learn: Are the Ethereum Killers Still Deadly?
    • Learn: What Ethereum Tech Trends Are Weathering the Bear Market?
    • Learn: How Ethereum’s token burns are making it a deflationary cryptocurrency?
    • Learn: A few things to know about Ethereum's Shanghai Upgrade
    • Learn: The Role of Enterprise Ethereum
    • Learn: Understanding Layer 2 Scaling Solutions for the Ethereum Network
    • Learn: The Battle of Giants: Bitcoin vs Ethereum
    • Learn: Cryptography, Smart Contracts and Distributed Networks
    • Learn: The Memecoin Grift and How It Threatens Ethereum Culture
    • Learn: What Is Ethereum’s ‘Data Availability' Problem, and Why Does It Matter?
    • TL;DR 👀
  • 👛Wallet
    • What is a Blockchain Wallet?
    • Hardware / Software Wallet
    • How to Get Your First Cryptocurrency
    • Setting up Metamask Wallet
    • Learn: How to connect the Avalanche network to MetaMask?
    • Learn: How to pass on your crypto when you die?
    • Learn: What are hierarchical deterministic (HD) crypto wallets?
    • Learn: Pros and Cons of Digital Wallets
    • Learn : How Web 3.0 Wallets Are Redefining Digital Asset Security?
    • Learn: Open source: Buzzword or real security for crypto wallets?
    • TL;DR 👀
  • 🌕New & Rising Protocols
    • Binance
    • NEAR
    • Solana
    • Fantom
    • Polygon
    • Cardano
    • Polkadot
    • Cosmos
    • Harmony
    • Cronos
    • Optimism
    • Terra
    • Who Will Win the L1 Wars?
    • Learn: New Layer 1 Blockchains Are Expanding the DeFi Ecosystem But No Eth Killers Yet
    • Learn: Is an Increased Focus on Layer-2 Scaling and ZK Technology Justified?
    • Learn: What Are the Stakes in the SEC vs. Ripple Case?
    • Learn: What is The Graph, and how does it work?
    • TL;DR 👀
  • 📈Decentralized Finance (DeFi)
    • CEX vs DEX
    • CeFi vs DeFi
    • Algorithmic Stablecoins
    • Airdrop
    • Liquidity Pool
    • Impermanent Loss
    • Swapping
    • Wrapped Token
    • Arbitrage Opportunities
    • Staking
    • Yield Farming
    • Total Value Locked (TVL)
    • Gas Fees
    • Lending & Borrowing
    • Useful Tools
    • Activity: Uniswap & Pancake Swap
    • Learn: Automated Market Makers (AMMs) in DeFi
    • Learn: Crypto Moving towards ESG: What Is Regenerative Finance (ReFi)
    • Learn: What Is dYdX? Understanding the Decentralized Crypto Exchange
    • Learn: It's A Wrap - DeFi in 2022
    • Learn: Why DeFi should expect more hacks this year?
    • Learn: The Security Challenges of DeFi
    • Learn: The Promising Future of Decentralized Social Media on Web 3.0
    • Learn: Can CBDCs, Tokenized Deposits, Stablecoins and DeFi Coexist?
    • Learn: The Increasing Popularity of DeFi and Its Potential to Disrupt Traditional Finance
    • Learn: The future of DeFi is ReFi
    • Learn: DeFi aggregation
    • TL;DR 👀
  • 🙈Non-Fungible Token (NFT)
    • What are NFTs?
    • Case Study
    • Storage
    • Who are the Players?
    • NFT Marketplace
    • NFT Useful Resources
    • Activity: Mint Your Own NFT
    • Learn: How You Can Prevent Hackers From Stealing Your NFTs?
    • Learn: What Is an NFT Floor Price?
    • Learn: Should Bored Ape buyers be legally entitled to refunds?
    • Learn: China’s view of NFTs different from rest of the world’s
    • Learn: NFTs IRL: How Digital Collectibles Are Forging Offline Experiences
    • Learn: How NFT Brands Can Cut Through The Noise
    • Learn: How Web3 disrupts the music sector?
    • Learn: Unlockable content in NFTs
    • Learn: Why Meta Matters in NFTs?
    • Learn: Should NFT Marketplaces Become Centralized?
    • Learn: Hermès vs. MetaBirkins: The NFT Case That Could Have Major Trademark and Artistic Consequence
    • Learn: What are phygital NFTs, and how do they work?
    • Learn: What is NFT ticketing and how does it work?
    • Learn: Why Solana NFT marketplace is seeing less active users?
    • Learn: NFTs and Intellectual Property
    • Learn: How AI Is Changing Artistic Creation and Challenging IP Laws?
    • Learn: The Future of NFTs: Exploring Dynamic NFTs and Their Versatile Use Cases
    • Learn: NFTs in the event and ticketing industry
    • Learn: What is NFT rarity, and how to calculate it?
    • Learn: What happens to your NFTs when you die?
    • Learn: Dogecoin-Like Spike in Milady NFTs After Elon Musk’s Tweet, But Will It Last?
    • Learn: What are NFT royalties, and how do they work?
    • Learn: How developers aim to store crypto inside NFTs?
    • Learn: Generative Art NFTs: What Are They & Why Are They So Popular?
    • TL;DR 👀
  • 💗Metaverse
    • What is the Metaverse?
    • Metaverse Economy
    • Metaverse Companies
    • GameFi
    • Learn: Are We in the Metaverse Yet?
    • Learn: Can the Metaverse exist without blockchain?
    • Learn: Can the Metaverse Facilitate Sustainable Growth of Defi Systems?
    • Learn: What is the role of biometrics in the metaverse?
    • Learn: Can metaverse be the future court?
    • Learn: Metaverse Fashion Is on the Rise, but for Whom?
    • Learn: Sustainability in the Metaverse: Challenges and Opportunities
    • Learn: How To Build A Responsible Metaverse?
    • Learn: What is a VTuber, and how do you become one?
    • Learn: How proof-of-identity provides human experiences?
    • Learn: The “Metaverse” Next Frontier for Business: Impact And Challenges
    • Learn: The 5 Biggest Misconceptions About The Metaverse
    • Learn: Why culture and ownership are critical to the metaverse?
    • TL;DR 👀
  • 👾Career in Web3 (coming soon)
    • Developers
    • Moderators
    • Community Managers
    • UI/ UX Designers
    • Digital Fashion Designers
  • 🌱Sustainability (Coming Soon)
    • Industry Effort
    • Co-author
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  • What is a hash function?
  • What does a hash function do?
  1. Blockchain Fundamentals

Hash Functions and Cryptography

PreviousPublic and Private KeysNextSharding

Last updated 2 years ago

What is a hash function?

A term like 'hash function' can mean several things to different people depending on the context. For hash functions in cryptography, the definition is a bit more straightforward. A hash function is a unique identifier for any given piece of content. It’s also a process that takes plaintext data of any size and converts it into a unique ciphertext of a specific length.

The first part of the definition tells you that no two pieces of content will have the same hash digest, and if the content changes, the hash digest changes as well. Basically, hashing is a way to ensure that any data you send reaches your recipient in the same condition that it left you, completely intact and unaltered.

But wait –– doesn’t that sound a lot like encryption? Sure. They’re similar, but encryption and hashing are not the same things. They’re two separate cryptographic functions that aid in facilitating secure, legitimate communications. So, if you hear someone talking about “decrypting” a hash value, then you know they don’t know what they’re talking about because, well, hashes aren’t encrypted in the first place.

We’ll speak more about the difference between these two processes a little later. But for now, let’s stick with the topic of hashing. So, what does hashing look like?

Here's a basic illustration of how the hashing process works:

What does a hash function do?

One purpose of a hash function in cryptography is to take a plaintext input and generate a hashed value output of a specific size in a way that can’t be reversed. But they do more than that from a 10,000-foot perspective. You see, hash functions tend to wear a few hats in the world of cryptography. In a nutshell, strong hash functions:

  • Ensure data integrity

  • Secure against unauthorized modifications

  • Protect stored passwords

  • Operate at different speeds to suit different purposes

Ensure data integrity

The example above is of a digitally signed email that’s been manipulated in transit via a MitM attack. The hash digest changes completely when any of the email content gets modified after being digitally signed, signaling that it can’t be trusted.

So, now someone receives the message and they want to know it’s legitimate. What they can do then is use the hash value your digital signature provides (along with the algorithm it tells them you used) to re-generate the hash themself to verify whether the hash value they create matches the one you sent. If it matches –– great, it means that no one has messed with it. But if it doesn’t… well, red flags should go up, and they should know to not trust it.

Even if something tiny changes in a message — you capitalize a letter instead of using one that’s lowercase, or you swap an exclamation mark where there was a period — it’s going to result in the generation of an entirely new hash value. But that’s the whole idea here — no matter how big or small a change, the difference in hash values will tell you that it isn’t legitimate.

Secure against unauthorized modifications

One of the best aspects of a cryptographic hash function is that it helps you to ensure data integrity. But if you apply a hash to data, does it mean that the message can’t be altered? No. But what it does is inform the message recipient that the message has been changed. That’s because even the smallest of changes to a message will result in the creation of an entirely new hash value.

Think of hashing kind of like you would a smoke alarm. While a smoke alarm doesn’t stop a fire from starting, it does let you know that there’s danger before it’s too late.

Enable you to verify and securely store passwords

Nowadays, many websites allow you to store your passwords so you don’t have to remember them every time you want to log in. But storing plaintext passwords like that in a public-facing server would be dangerous because it leaves that information vulnerable to cybercriminals. So, what websites typically do is hash passwords to generate hash values, which is what they store instead.

Operate at different speeds, suiting different purposes

It’s also important to note that hash functions aren’t one-size-fits-all tools. As we mentioned earlier, different hash functions serve different purposes depending on their design and hash speeds. They work at different operational speeds — some are faster while others are much slower. These speeds can aid or impede the security of a hashing algorithm depending on how you’re using it.

An example of where you’d want to use a fast hashing algorithm is when establishing secure connections to websites. In this example, having a faster speed matters because it helps to provide a better user experience. However, if you were trying to enable your websites to store passwords for your customers, then you’d definitely want to use a slow hashing algorithm. At scale, this would require a password-cracking attack (such as brute force) that takes up more time and computing resources for cybercriminals. You don’t want to make it easy for them, right?

Source

Hash functions are a way to ensure data integrity in . Hash functions serve as a check-sum, or a way for someone to identify whether data has been tampered with after it’s been signed. It also serves as a means of identity verification.

For example, let’s say you’ve logged on to public Wi-Fi to send an email. (Don’t do that, by the way. It can be very insecure.) So, you write out the message, sign it using your digital certificate, and send it on its way across the internet. This is what you might call prime (MitM) territory — meaning that someone could easily intercept your message (again, because public wireless networks are notoriously insecure) and modify it to suit their purposes.

But password hashes on their own aren't enough to protect you against certain types of attacks, including brute force attacks. This is why you first need to add a salt. A is a unique, random number that’s applied to plaintext passwords before they’re hashed. This provides an additional layer of security and can protect passwords from password cracking methods like rainbow table attacks.

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public key cryptography
man-in-the-middle attack
salt
thesslstore
A simple illustration of what a hash function does by taking a plaintext data input and using a mathematical algorithm to generate an unreadable output.