Mint and configure tokens and accounts.
The ability to verify smart contracts is crucial for various applications, especially in the DeFi sector. Introducing Smart Contract Verification on Hedera bolsters transparency and security between smart contract owners and users. This verification process is integral in establishing trust in the smart contracts deployed on the Hedera network.
The publicly reported transaction count on Hedera does not include the intra-node gossip communication needed to reach consensus. Only transactions submitted and paid for by external parties are included in the TPS count. Read this article to learn how to calculate TPS count from on-chain data anyone can access.
Contributors to the Hedera codebase continually innovate based on how well the system responds to real-world traffic load and scenarios. Read this article to learn how recent efforts have resulted in an optimization in the core algorithms, specifically optimizing how nodes select events as other-parents to ensure a more efficient hashgraph is created during the consensus process.
With Hedera becoming increasingly EVM-equivalent, the need to maintain a separate library like hethers.js is diminishing. Hedera core contributors are announcing the deprecation of the hethers.js library by October 20, 2023.
In this step-by-step guide, we'll show you how to create a Hedera DApp using React, Material UI, Ethers, and TypeScript. With the help of the Create React App (CRA) Hedera DApp template, you'll be able to seamlessly integrate popular wallets like MetaMask, Hashpack, and Blade. You'll learn how to query the mirror node and incorporate HTS features, enabling users to effortlessly manage and transact with HTS tokens.
AI and blockchain are two technological trends that have captured everyone’s attention. The learning aspect of AI, coupled with Blockchain's immutable nature, introduces a revolutionary change in how data can be processed and utilized. In this article, you'll see how to combine the strengths of AI and blockchain technology by creating a ChatGPT plugin that interacts with Hedera.
Hedera consensus nodes must strike a delicate balance between Hedera security and EVM security models. The latest security model for Hedera smart contracts provides greater clarity and additional protections relative to its predecessor.
The security model of the Hedera Smart Contract Service has been updated with the mainnet services release v0.35.2 (March 2023). The updated model aligns the behaviors of the Hedera Smart Contract Service token system contracts with those of EVM and typical token APIs such as ERC 20 and ERC 721. Read this article to learn specifically what changed, what it means for developers, and what actions you should take.
In this step-by-step tutorial, you will create a simple counter dApp on the Hedera network using Solidity, React JS, MetaMask, and Ethers JS. The goal with this example is to help you understand the fundamentals of dApp development, making it easier for you to create more complex dApps in the future.
In this tutorial, we'll walk you through the process of connecting to MetaMask using create react app. We'll also guide you through the steps to transfer HBAR to the MetaMask wallet. By the end of this tutorial, you'll have a solid understanding of how to seamlessly integrate MetaMask into your Hedera decentralized application. So, let's get started! 🎉
The vision of Soulbound tokens is visionary, expansive, and controversial. The name “Soulbound” entices excitement and groans in most conversations. I would argue that there are a few reasons why neither kind of Identity Token described above realizes the Soulbound Token vision as it has been articulated.
Learn more about the possibilities of token keys and their edge cases. In this blog post, you'll find technical examples showing you what token keys can do.
This tutorial helps smart contract developers understand the traceability information for contract transactions that is provided by the mirror nodes. Specifically, you will learn how to view contract actions, state changes, and logs.
Learn how you can get your contracts ready to make rent payments and avoid expiration
This blog post explains Hedera's pricing structure and renewal windows for contract rent payments. Smart contract rent is a key topic of discussion by Leemon and others in the layer 1 network space. Rent fees are an economically and technically viable approach to manage smart contract state storage.
Metadata determines the health of your NFT. How to structure your metadata correctly to make it easier for NFT tooling to scrape and interpret your NFT.
The ability to write tests for Smart Contracts using solidity allows for more efficient testing leading to catching more bugs early on and providing security to your users. Learn how to set up Foundry on your Hedera project to start testing now!
NFT royalty fees allow you to charge a fractional fee when transferring NFTs between users or set a fallback fixed fee. But what about NFT royalty fee edge cases? This blog post looks at questions such as what happens when a user is not associated with the fallback fee and no fungible value is exchanged, or the user doesn't have any fallback fee balance.
The implementation of HIP-573 in mainnet release v0.31 (November 10th, 2022) enables token creators whose tokenomics require custom fees and different collection accounts to exempt collectors from paying custom fees when exchanging token units. Learn now how to create a fungible token with multiple fee collectors and discover what happens when you transfer some tokens from one collector to another.
In use cases like DeFi, contracts often need to mint, burn, or transfer 0 units of a token due to integer rounding. The implementation of HIP-564 in release 0.31 of Hedera Services enables smart contract developers to specify a zero value for contract functions performing token operations. In this article, you will learn how to use this capability on Hedera.
In this tutorial learn how to auto-create Hedera accounts by sending HBAR and tokens to an alias.
The Hedera Portal is where developers create test accounts that enable building applications in development, risk-free, and cost-free environments (testnet, preview, or local network). The portal is a vital part of the Hedera ecosystem because it is effectively an onramp onto Hedera test networks and a faucet for test HBAR. This article provides an overview of the Hedera Portal and shows how you can start creating testnet accounts that use different types of keys.
This November, token information returned by getAccountInfo, getAccountBalance and getContractInfo will be deprecated. For exchanges, wallets and dapp developers, users will need to use the mirror node REST API to access this information.
The JSON-RPC Relay provides excellent usability for developers with existing workflows dependent on Ethereum developer tools like Truffle, Web3js, Ethers, and Hardhat to seamlessly build on Hedera. In addition, it makes it easy to integrate with Metamask.
Learn how to send and receive HBAR to and from Hedera contracts. Part 1 of the series focused on using the Hedera SDKs. This second part goes over transferring HBAR to and from contracts using Solidity.
In this article, you will learn how to transfer a Hedera Token Service (HTS) token from a contract to another contract using solidity. You will then use the same contract to transfer a token to a Hedera account using an ERC Standard Call.
The Hedera JSON RPC Relay enables developers to use their favorite EVM-compatible tools such as Truffle, Hardhat, Web3JS, EthersJS, to deploy and interact with smart contracts on the Hedera network. The relay provides applications and tools seamless access to Hedera while masking implementation complexities and preventing reductions in performance, security, and scalability.
This tutorial shows you how to deploy smart contracts on Hedera using Truffle and the JSON RPC Relay.
The Hedera network provides a powerful decentralized platform, supporting native tokenization, robust smart contracts, and more. HIP-329 introduced the ability to use the CREATE2 opcode on the Hedera network. The power of CREATE2 comes from the deterministic nature of the deployment, meaning the address is easy to compute even before a smart contract gets deployed to the address. Pairing the predictable low fees and scalability of Hedera with the power of the CREATE2 opcode enables users to build incredible user experiences. Read this article for an introduction to the CREATE2 opcode.
Learn how to exchange Hedera Tokens between entities using the SDK. We'll start by creating an account as a token treasury, then explain how to associate tokens to contracts, how to update contracts, and finally, how to transfer tokens.
In this tutorial, you will learn how to configure staking options for Hedera accounts and contracts programmatically. Perhaps you need to integrate these staking capabilities with wallets, decentralized applications, marketplaces, or other cool things you may be building on Hedera.
Smart contracts on Hedera can hold and exchange value in the form of HBAR, Hedera Token Service (HTS) tokens, and even ERC tokens. This is fundamental for building decentralized applications that rely on contracts in areas like DeFi, ESG, NFT marketplaces, DAOs, and more. In this tutorial, you will learn how to send and receive HBAR to and from Hedera contracts. Part 1 focuses on using the Hedera SDKs.
Learn how to create a completely keyless contract to manage your Hedera Tokens. You will create a fungible token that has a contract as treasury and auto-renew account using two different methods.
Learn how to create a non-fungible token using Hedera SDK and a Solidity Smart Contract! In this article, you will discover how to create a token by simply calling a Hedera SDK method and how to do the same thing by compiling and executing a contract.
Learn how to create a fungible token using Hedera SDK and a Solidity Smart Contract! In this article, you will discover how to create a token by simply calling a Hedera SDK method and how to do the same thing by compiling and executing a contract.
There is a new buzzword in Web3 Identity - “Soulbound Tokens” - a very expressive name for non-transferable non-fungible tokens (NFTs) intended to represent an aspect of someone's identity, skills, or qualifications. In this posting, we consider what an early implementation of Soulbound Tokens might look like, and how they can be easily implemented on the Hedera network, leveraging the powerful capabilities of the Hedera Token Service (HTS).
The Hedera Local Node is available for developers to start testing and debugging their applications. This article will focus on setting up your local network, starting it, and ensuring that it is operating correctly by submitting transactions and then querying your local mirror node.
Core contributors are now focused on an important pricing update for the Hedera Smart Contract service, recently approved by the Coin Committee of the Hedera Governing Council. This update rolls Smart Contract Hedera API (HAPI) fees into gas fees and removes the cover charge for HAPI fees when making a ContractCall transaction.
The JSON-RPC Relay makes it easy for existing libraries, development tools, and wallets to work effortlessly on Hedera. Examples include support for wallets, such as Metamask, libraries, such as ethers.js and web3.js, and developer tools, such as Truffle and Hardhat.
For Earth Day 2022, Envision Blockchain is proud to announce the release of the 2.0 version of the Guardian. Guardian v2.0 delivers new features to expand on what was built and grow the Hedera Guardian ecosystem.
Gamers spend on average 14.8 hours per week gaming, with many going even further beyond that—to the point of it becoming a second job. What if this hobby could become profitable for the average gamer? Previous articles covered the subjects of HCS-based game records and its possible use cases. This third article synthesizes these concepts into a new subject: multi-game economies.
HashConnect is an open source library that is developed by the HashPack team. This library enables decentralized applications (dApps) to connect to a user’s wallet and send transactions for them to sign and submit to the Hedera network nodes.
To build dApps, one has the raw power of the official SDK at their disposal; but what if that's sometimes too much? What if there was a more human-centric way of writing code similar to other mature, well-known tools in this space of Smart Contract development? Tools such as the likes of ethers, hardhat or ganache, to name but a few? Well now you can! Succinct, bold and expressive; programming on Hedera has never been this easy!
All Hedera entities will require renewal fees. Solidity smart contracts are the first. Get to know the lifecycle of entities and your options to design self-sustaining Solidity smart contracts.
“Play-to-Earn” gaming has grown to a $3 Billion dollar market in less than a year, and investors are taking notice. The era of play-to-earn gaming has begun, presenting an exciting new frontier for game development – as well as several potential pitfalls. All the risks associated with decentralized finance are also present in play-to-earn, namely smart contract exploits. But the Hedera Consensus Service (HCS) offers a solution to these inherent problems.
The Smart Contracts 2.0 service utilizes the Hyperledger Besu EVM. As part of the preparation a number of performance optimizations were contributed by Hedera to the Hyperleger codebase. Hedera’s implementation is completely open-source but developers of the service have received questions around the specific optimizations implemented and we wanted to summarize what’s been improved.
Events in Solidity provide a way to log things and actions that take place in your smart contracts. In this article, you will learn how to get human-readable event information from contract logs using transaction records and mirror nodes.
Dallas, TX - Feb 3, 2022 - Hedera Hashgraph, the most used, sustainable, enterprise-grade public network for the decentralized economy, today announced a significant upgrade through the mainnet launch of the Hedera Smart Contracts 2.0.
The Hedera Smart Contract Service enables you to build decentralized applications and protocols that scale with Solidity smart contracts. Recent updates to this service include Ethereum Virtual Machine (EVM) upgrades, database architecture modifications, and support for Hedera Token Service. Whether you’re new to smart contract development or migrating from another smart contract platform, use Hedera to develop and deploy fast, low-cost, and carbon-negative smart contracts. In this article you will learn how to write a getter-setter smart contract in Solidity and deploy it on the Hedera network.
In Part 1, you learned how to write a getter-setter smart contract in Solidity and deploy it on the Hedera network. Now let’s write and deploy a Solidity smart contract that integrates with the Hedera Token Service (HTS). Whether you’re new to smart contract development or migrating from another smart contract platform, use Hedera to develop and deploy fast, low-cost, and carbon-negative smart contracts.
Solidity is the world's most popular way to write smart contracts. Hedera Smart Contracts 2.0 is a more scalable way to run smart contracts on the Hedera network. Understand the basics of Solidity and the Ethereum Virtual Machine.
Smart contracts play a critical role in building the trust layer of the internet. Used to manage autonomous logic that doesn’t rely on a centralized intermediary, server, or custom governance model, smart contracts can power core infrastructure like decentralized finance. While the Hedera Smart Contract Service is EVM compatible and runs Solidity, with the availability of Smart Contracts 2.0 on the Hedera testnet it now does so with a few added bonuses as only Hedera and the soon to be open-sourced hashgraph can.
With the high number of transactions that the Hedera Network is able to process every second, keeping this transaction history in all the network nodes for all time would eventually turn those nodes into massive data centers. Mirror nodes help address that issue by separating the consensus operations and the record keeping. In this article you will learn about mirror nodes and how to use them for your applications.
In this blog post, you will learn how you can start developing on the Hedera network today. After reading this article you will have everything you need to start developing, understand the essentials to begin, and know where to get help.
In this article, we hear from community member John Conway on his experience building a Chess Application on the Hedera Consensus service. John goes into the tech stack he used, the development process, and what he learned.
Learn how to use HTS capabilities that help you manage your tokens. More specifically, you will see how to pause a token, freeze an account, wipe a token, and delete a token.
Learn how to take advantage of the flexibility you get when you create and configure your tokens with HTS. More specifically, you will enable and disable a KYC flag for a token, update token properties, and schedule transactions (like a token transfer).
Hedera Token Service (HTS) enables you to configure, mint, and manage tokens on the Hedera network without the need to set up and deploy a smart contract. Tokens are as fast, fair, and secure as hbar and cost a fraction of 1¢ USD to transfer. Let’s look at some of the functionality available to you with HTS.
At Hedera, we’re often asked how Hedera Token Service (HTS) tokens map to the most ubiquitous fungible and non-fungible token models: ERC20, ERC721, and ERC1155. Let’s dive deeper into the Hedera Token Service and highlight how Hedera token models and ERC token models overlap.
Developers looking to utilize NFTs on Hedera can reference this developer quick-start tutorial to start building NFTs right into their application. We’ll dive into a few real-world use cases and learn how to mint an NFT for them using code examples.
HIP-17: NFT (Non-Fungible Token) Support and HIP-18: Custom Hedera Token Service Fees are available in Hedera Services Code v0.17.4 on testnet and mainnet. In addition, NFT metadata standards for the Hedera Token Service, found in HIP-10: Token Metadata JSON Schema, have become a recommended best practice.
Scheduled Transactions is a new capability available on Hedera that enables multiple parties to easily, inexpensively, and natively schedule and execute any type of Hedera transaction together.
How can we create a decentralized eBay that remains affordable, environmentally friendly, and fast? For this challenge, we’ve built an open-source NFT auction using Hedera Token Service and Hedera Consensus Service. We'll test it out with a live auction soon.
Fees for the CryptoCreate Hedera API call have increased to $0.05 USD. Additionally, a new process using Hedera Improvement Proposals (HIPs) has been implemented to ensure the developer community has input and transparency in key network decisions.
Hedera21 has officially ended with over 600 participants and 60 projects submitted. We had 8 challenges from our sponsors Google, eftpos, Bitgo, DLA Piper, BCW, Chopra Foundation, UCL, Armanino — each bringing an exciting opportunity for hackers to build something new with the Hedera Token Service. Now that you’ve finished your Hedera21 project, here is a step-by-step guide to migrating to the public Hedera mainnet.
For tokenization to reach its potential, fees must be both small relative to the value transfer and predictable. The Hedera Token Service provides both.
For individuals, being willing to change your mind is generally seen as a good thing – it suggests flexibility and a willingness to accept new data or evidence, even if it contradicts a previously held belief. Not so for a consensus node in a distributed ledger.
In part 2 of the tutorial, we'll continue using the .NET SDK to manage our Hedera Token Service custom token, PLAYTOKEN, checking our balance and transferring tokens between accounts.
In this tutorial, you'll learn how to use the new Hedera Token Service with the community-maintained .NET SDK. We'll mint a PLAYTOKEN on the Hedera testnet and in so doing learn some of the basic definition and functionality available to custom tokens on Hedera.
The Hedera Token Service (HTS) is used via a robust set of APIs for the configuration, minting, and management of tokens on Hedera, without needing to set up and deploy a smart contract. In Part 3 of this series, let's look at the different types of compliance functionalities that are available within the Hedera API (HAPI):
The Hedera Token Service (HTS) is used via a robust set of APIs for the configuration, minting, and management of tokens on Hedera, without needing to set up and deploy a smart contract. In Part 2 of this series, let's look at the different types of administration functionalities that are available within the Hedera API (HAPI):
The Hedera Token Service (HTS) is used via a robust set of APIs for the configuration, minting, and management of tokens on Hedera, without needing to set up and deploy a smart contract. Let’s take a look at why you’d consider using it versus something like a fungible token with a smart contract on the Ethereum Blockchain, and the different types of functionalities that are available within the Hedera API (HAPI):
If you’re utilizing the Hedera API (HAPI) to build applications on the testnet or mainnet, you’ll need to review deprecations and additions coming in v0.8.0 and v0.9.0 of the Hedera Services Codebase.
Verifiable Credentials (VC) and Decentralized Identifiers (DIDs) are two different but related identity standards progressing in the W3C – both of which allow for a Decentralized Ledger Technology (DLT) to provide supporting infrastructure.
At Hedera, we’re constantly looking at ways that we can improve our onboarding experience for new developers and enthusiasts within our community - always with a goal to become the most widely used distributed public ledger in the market. I’m excited to share the first of a variety of new changes to the Hedera website, portal, and documentation that we’ve made as part of these ongoing efforts.
While you may be familiar with Hedera’s unique consensus algorithm, hashgraph, which (even while throttled) allows us to process 10,000+ cryptocurrency transactions per second - or our Governing Council, which LG and Avery Dennison recently joined, there are a number of notable differences in functionality between our network and the likes of Ethereum, Polkadot, or EOS. Let’s dive into a few of the lesser-known things that you can do with Hedera “out of the box”.
Hedera recently hosted its very first monthly “Engineering Insights” webinar, hosted by Donald Thibeau, Director of Product Management, and attended by members of the Hedera developer community.
The Hedera previewnet will use a codebase that's still under development by the Hedera team. It’s designed to offer developers early exposure to features and functionalities that will eventually make their way to the mainnet.
Everyone now has access to real-time and historical raw data files for the Hedera testnet and mainnet via public AWS and GCP buckets. In addition, the Hedera-ETL tool and beta mirror node software is available, including one-click deploy in GCP Marketplace.
Hedera has brought verifiability and transparency to the PDFs on Hedera.com with "Trust Bucket" — a hackathon submission for Hedera20 that offers verifiable object storage for Amazon S3 using the Hedera Consensus Service.
In Proof of Stake (PoS) systems, 'slashing' refers to the possibility of a node determined to be breaking the rules of the protocol being punished by the loss of some or all of the stake (coins) they had put forward.
Regulations like the General Data Protection Regulation (GDPR) in the EU and the California Consumer Privacy Act (CCPA) specify strict rules for how businesses collect, store, and share individuals’ personal data. Hedera Consensus Service can uniquely compliantly manage this data while also providing evidence of a businesses' response to meet these growing requirements.
Hedera mirror nodes store transactions that have occurred on the Hedera network, exposing them to consumers and developers alike through user interfaces (explorers) and APIs. We’re excited to see that the Hedera ecosystem is constantly growing, with each new service providing unique offerings.
Nodes in a hashgraph network apply a 2/3 threshold in the virtual voting procedure – as soon as more than this fraction of consistent votes (or vote stake) are counted on the fame of a particular witness, then that election is complete. So why 2/3 and not some other fraction? It turns out that requiring nodes count just over 2/3 votes is the best compromise between defending against two different types of attacks.
The final part of the series, part 4 goes further into the application network beginning with mirror nodes. We'll finish the core concepts required for the Java tokenized asset on HCS demo application.
The beginning of the end, part 3 starts the focus on the code. We'll provide a Java demo application to help map an ERC-20-like example to an application network using Hedera Consensus Service.
Part 2 of the 4-part series looks at the more decentralized architecture models and options for managing a token using Hedera Consensus Service application networks. In this article, you'll learn more about their potential trade-offs before diving into the code.
Tokens are an exciting new way to manage assets. To date, they've mainly been created through the use of Solidity smart contracts. This 4-part blog series provides an early look at how we can start to achieve similar use cases with Hedera Consensus Service for improved speed and lower costs.
Are you a developer looking to get started building on the Hedera Hashgraph public network? Throughout this post, I’ll show you how to get your account credentials and on your way to deploying your application to the mainnet.
Learn how to get started with the Hedera community supported SDK for .NET. This tutorial walks you through creating an account on the Hedera testnet or mainnet and transferring HBAR cryptocurrency.
Today we kicked off Hedera20, our first fully virtual hackathon. Throughout the 6 week challenge, teams of up to 5 have the opportunity to build on the new Hedera Consensus Service (HCS), which brings a decentralized publish-subscribe architecture to any application. We couldn’t be more excited to see what gets developed, and we’re thrilled to provide a few new developer tools that can help you build with HCS during and beyond the hackathon.
Hedera is pleased to announce the early availability of beta tools that Hedera developers can use to manage the lifecycle of Decentralized Identifiers (DIDs) and Verifiable Credentials via the Hedera Consensus Service. We welcome feedback from the community on these tools.
Hedera Hashgraph is a public ledger. Nodes on the network collectively establish and maintain a consensus state for a set of application data. Clients interact with that state through API calls sent to the nodes of the network.
Many applications require knowing either the time at which a business transaction happened (for instance, submitting federal taxes before the deadline) or its order relative to other transactions (for instance, competing bids in markets or auctions) or both. Time, or order, will generally be used to assess validity of a transaction or priority relative to other transactions.
In this post, Developer Evangelist Cooper Kunz will show you how to build a web-based chat application that is decentralized on the Hedera Consensus Service (HCS).
For some consensus algorithms, it is possible to prove that they are Asynchronous Byzantine Fault Tolerant (ABFT). But what does that mean, and what are the practical implications? This blog will explore what an ABFT proof can guarantee about the correctness, finality, and liveness of a consensus algorithm.
Having up-to-date and accurate HBAR to USD conversion values is an important aspect of network operations at Hedera. We utilize the current price of HBAR across various applications and services. If you’ve ever wondered how we do that conversion, look no further.
Hedera enables a flexible and dynamic permissioning model for entities in consensus state via a hierarchical m-of-n transaction signature based authorization model. The ability to require multiple signatures for operations on entities in state is critical for security and usability of public ledgers.
Latency is the time from when a transaction is first sent out from one node, until a node has received it and calculated its consensus order and consensus timestamp, averaged over all nodes and all transactions. On the Hedera mainnet we are currently seeing a latency of approximately 2.5 seconds for transactions. This post will break down that 2.5 seconds.
Once a crypto account is created, hbars can be moved out of the account (causing the balance to drop) only if the transactions directing such movements are cryptographically signed by the private key(s) associated with the public keys.
Hedera charges fees based on the burden a particular smart contract transaction or query places on the nodes of the network. Although the concept originated from Ethereum, there are subtle yet key differences on Hedera.
The guiding principle of the fee model is that transactions and queries will have a fee that both reflects the amount of bandwidth, processing, and storage resources they consume, as well as the duration of that consumption.
Distributed ledger technologies (DLT) aren’t just built on code; they’re about community too. And while we might wish for universal agreement, any community worth the name will have its share of disagreement and dispute.
The public Hedera network is dedicated to that which the underlying hashgraph algorithm is optimized for – securely and fairly ordering transactions. Without the burden of execution and storage, the nodes of the Hedera mainnet can perform that step with high throughput and low latency.
The fundamental value proposition of a distributed ledger is that participants need not have special trust in any single node maintaining the state. Hedera’s state proofs ensure that clients querying the state can be given the necessary confidence that any data, even if returned by a single node, does indeed accurately represent the consensus state as maintained by the full network.
A technical deep-dive into how the hashgraph consensus algorithm allows for practical cryptocurrency micropayments and the considerations made when designing our open source example applications for the community testing program, to scale to up to 100,000 unique community testers.
Proxy staking in Hedera hashgraph will allow the stake of millions of account holders to be used towards consensus even if not directly participating as a node. Nodes will receive significant compensation for staking, to incentivize them to do all the effort of being a node. Proxy stakers will also receive very small amounts in order to incentivize them to do the small amount of effort of choosing reliable nodes to which they can proxy stake.
Hedera charges rent for storing crypto accounts, files, and smart contracts in the consensus state maintained by all nodes to both guard against that state growing without bound and to fund payments to those nodes to compensate for their storage costs.
A deepfake is a growing problem, a fraudulent copy of an authentic video or image, manipulated to create an erroneous interpretation of the events. A distributed ledger can play a role in establishing the provenance of a video and therefore aid in combating deepfakes.
If smart contracts are to model real-world business processes and interactions, they must be connected to that world. Oracles — whether software, hardware, or human — enable that connection. Hedera provides a number of features that uniquely enables smart contract oracles.
After a client submits a transaction to Hedera, the client may seek confirmation that the transaction was added to consensus state and also to perhaps retrieve information associated with that addition. As an example, if the transaction is a transfer of hbars for the purchase of a coffee, then the coffee shop will likely want confirmation that its account received the customer’s payment before pouring the brew.
Online gaming architectures have historically relied on an intermediary to facilitate the game play — running centralized servers to which users would connect in order to find opponents and then managing the game state (e.g. where all characters are in a Massively Multiplayer Online (MMO) game, or how much gold each has, or where the pieces are in chess).
Distributed Ledger Technologies (DLTs) commonly have simple and inflexible forms of immutability. Hedera supports a more flexible form of controlled mutability, which allows certain changes under certain circumstances, but prevents other types of changes. One area where this is particularly important is for smart contracts.
Some consensus algorithms are fragile — they cannot adapt to changes, either in the membership of nodes, or in the influence of those nodes towards consensus. The result is that such changes cause consensus to be prevented or corrupted. This can be a problem for some types of distributed ledgers, but it is not a problem for Hedera.
The highest security standard for consensus algorithms is known as Asynchronous Byzantine Fault Tolerance (ABFT). The hashgraph algorithm, as used in the Hedera public ledger, achieves this gold standard, with a mathematical proof that it is ABFT. This proof-of-stake consensus system was first proved to be ABFT in a rigorous math proof published in 2016. That proof has now been verified by computer in a formal verification completed by a Carnegie Mellon University professor — and we think it is important to explain what that means.
It’s a wonderful bit of irony that the Fiddler on the Roof character singing the above is named ‘Hodel’.