Author: Gamals Ahmed, CoinEx Business Ambassador
ABSTRACT
The DFINITY blockchain computer provides a secure, performant and flexible consensus mechanism. At its core, DFINITY contains a decentralized randomness beacon, which acts as a verifiable random function (VRF) that produces a stream of outputs over time. The novel technique behind the beacon relies on the existence of a unique-deterministic, non-interactive, DKG-friendly threshold signatures scheme. The only known examples of such a scheme are pairing-based and derived from BLS.
The DFINITY blockchain is layered on top of the DFINITY beacon and uses the beacon as its source of randomness for leader selection and leader ranking. A “weight” is attributed to a chain based on the ranks of the leaders who propose the blocks in the chain, and that weight is used to select between competing chains. The DFINITY blockchain is layered on top of the DFINITY beacon and uses the beacon as its source of randomness for leader selection and leader ranking blockchain is further hardened by a notarization process which dramatically improves the time to finality and eliminates the nothing-at-stake and selfish mining attacks.
DFINITY consensus algorithm is made to scale through continuous quorum selections driven by the random beacon. In practice, DFINITY achieves block times of a few seconds and transaction finality after only two confirmations. The system gracefully handles temporary losses of network synchrony including network splits, while it is provably secure under synchrony.
1.INTRODUCTION
DFINITY is building a new kind of public decentralized cloud computing resource. The company’s platform uses blockchain technology which is aimed at building a new kind of public decentralized cloud computing resource with unlimited capacity, performance and algorithmic governance shared by the world, with the capability to power autonomous self-updating software systems, enabling organizations to design and deploy custom-tailored cloud computing projects, thereby reducing enterprise IT system costs by 90%.
DFINITY aims to explore new territory and prove that the blockchain opportunity is far broader and deeper than anyone has hitherto realized, unlocking the opportunity with powerful new crypto.
Although a standalone project, DFINITY is not maximalist minded and is a great supporter of Ethereum.
The DFINITY blockchain computer provides a secure, performant and flexible consensus mechanism. At its core, DFINITY contains a decentralized randomness beacon, which acts as a verifiable random function (VRF) that produces a stream of outputs over time. The novel technique behind the beacon relies on the existence of a unique-deterministic, non-interactive, DKG-friendly threshold signatures scheme. The only known examples of such a scheme are pairing-based and derived from BLS.
DFINITY’s consensus mechanism has four layers: notary (provides fast finality guarantees to clients and external observers), blockchain (builds a blockchain from validated transactions via the Probabilistic Slot Protocol driven by the random beacon), random beacon (provides the source of randomness for all higher layers like smart contract applications), and identity (provides a registry of all clients).
DFINITY’s consensus mechanism has four layers
Figure1: DFINITY’s consensus mechanism layers
1. Identity layer:
Active participants in the DFINITY Network are called clients. Where clients are registered with permanent identities under a pseudonym. Moreover, DFINITY supports open membership by providing a protocol for registering new clients by depositing a stake with an insurance period. This is the responsibility of the first layer.
2. Random Beacon layer:
Provides the source of randomness (VRF) for all higher layers including ap- plications (smart contracts). The random beacon in the second layer is an unbiasable, verifiable random function (VRF) that is produced jointly by registered clients. Each random output of the VRF is unpredictable by anyone until just before it becomes avail- able to everyone. This is a key technology of the DFINITY system, which relies on a threshold signature scheme with the properties of uniqueness and non-interactivity.
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3. Blockchain layer:
The third layer deploys the “probabilistic slot protocol” (PSP). This protocol ranks the clients for each height of the chain, in an order that is derived determin- istically from the unbiased output of the random beacon for that height. A weight is then assigned to block proposals based on the proposer’s rank such that blocks from clients at the top of the list receive a higher weight. Forks are resolved by giving favor to the “heaviest” chain in terms of accumulated block weight — quite sim- ilar to how traditional proof-of-work consensus is based on the highest accumulated amount of work.
The first advantage of the PSP protocol is that the ranking is available instantaneously, which allows for a predictable, constant block time. The second advantage is that there is always a single highest-ranked client, which allows for a homogenous network bandwidth utilization. Instead, a race between clients would favor a usage in bursts.
4. Notarization layer:
Provides fast finality guarantees to clients and external observers. DFINITY deploys the novel technique of block notarization in its fourth layer to speed up finality. A notarization is a threshold signature under a block created jointly by registered clients. Only notarized blocks can be included in a chain. Of all RSA-based alternatives exist but suffer from an impracticality of setting up the thresh- old keys without a trusted dealer.
DFINITY achieves its high speed and short block times exactly because notarization is not full consensus.
DFINITY does not suffer from selfish mining attack or a problem nothing at stake because the authentication step is impossible for the opponent to build and maintain a series of linked and trusted blocks in secret.
DFINITY’s consensus is designed to operate on a network of millions of clients. To en- able scalability to this extent, the random beacon and notarization protocols are designed such as that they can be safely and efficiently delegated to a committee
1.1 OVERVIEW ABOUT DFINITY
DFINITY is a blockchain-based cloud-computing project that aims to develop an open, public network, referred to as the “internet computer,” to host the next generation of software and data. and it is a decentralized and non-proprietary network to run the next generation of mega-applications. It dubbed this public network “Cloud 3.0”.
DFINITY is a third generation virtual blockchain network that sets out to function as an “intelligent decentralised cloud,”¹ strongly focused on delivering a viable corporate cloud solution. The DFINITY project is overseen, supported and promoted by DFINITY Stiftung a not-for-profit foundation based in Zug, Switzerland.
DFINITY is a decentralized network design whose protocols generate a reliable “virtual blockchain computer” running on top of a peer-to-peer network upon which software can be installed and can operate in the tamperproof mode of smart contracts.
DFINITY introduces algorithmic governance in the form of a “Blockchain Nervous System” that can protect users from attacks and help restart broken systems, dynamically optimize network security and efficiency, upgrade the protocol and mitigate misuse of the platform, for example by those wishing to run illegal or immoral systems.
DFINITY is an Ethereum-compatible smart contract platform that is implementing some revolutionary ideas to address blockchain performance, scaling, and governance. Whereas
DFINITY could pose a credible threat to Ethereum’s extinction, the project is pursuing a coevolutionary strategy by contributing funding and effort to Ethereum projects and freely offering their technology to Ethereum for adoption. DFINITY has labeled itself Ethereum’s “crazy sister” to express it’s close genetic resemblance to Ethereum, differentiated by its obsession with performance and neuron-inspired governance model.
Dfinity raised $61 million from Andreesen Horowitz and Polychain Capital in a February 2018 funding round. At the time, Dfinity said it wanted to create an “internet computer” to cut the costs of running cloud-based business applications. A further $102 million funding round in August 2018 brought the project’s total funding to $195 million.
In May 2018, Dfinity announced plans to distribute around $35 million worth of Dfinity tokens in an airdrop. It was part of the company’s plan to create a “Cloud 3.0.” Because of regulatory concerns, none of the tokens went to US residents.
DFINITY be broadening and strengthening the EVM ecosystem by giving applications a choice of platforms with different characteristics. However, if DFINITY succeeds in delivering a fully EVM-compatible smart contract platform with higher transaction throughput, faster confirmation times, and governance mechanisms that can resolve public disputes without causing community splits, then it will represent a clearly superior choice for deploying new applications and, as its network effects grow, an attractive place to bring existing ones. Of course the challenge for DFINITY will be to deliver on these promises while meeting the security demands of a public chain with significant value at risk.
1.1.1 DFINITY FUTURE
- DFINITY aims to explore new blockchain territory related to the original goals of the Ethereum project and is sometimes considered “Ethereum’s crazy sister.”
- DFINITY is developing blockchain-based infrastructure to support a new style of the internet (akin to Ethereum’s “World Computer”), one in which the internet itself will support software applications and data rather than various cloud hosting providers.
- The project suggests this reinvented software platform can simplify the development of new software systems, reduce the human capital needed to maintain and secure data, and preserve user data privacy.
- Dfinity aims to reduce the costs of cloud services by creating a decentralized “internet computer” which may launch in 2020
- Dfinity claims transactions on its network are finalized in 3–5 seconds, compared to 1 hour for Bitcoin and 10 minutes for Ethereum.
1.1.2 DFINITY’S VISION
DFINITY’s vision is its new internet infrastructure can support a wide variety of end-user and enterprise applications. Social media, messaging, search, storage, and peer-to-peer Internet interactions are all examples of functionalities that DFINITY plans to host atop its public Web 3.0 cloud-like computing resource. In order to provide the transaction and data capacity necessary to support this ambitious vision, DFINITY features a unique consensus model (dubbed Threshold Relay) and algorithmic governance via its Blockchain Nervous System (BNS) — sometimes also referred to as the Network Nervous System or NNS.
1.2 DFINITY COMMUNITY
The DFINITY community brings people and organizations together to learn and collaborate on products that help steward the next-generation of internet software and services. The Internet Computer allows developers to take on the monopolization of the internet, and return the internet back to its free and open roots. We’re committed to connecting those who believe the same through our events, content, and discussions.
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1.3 DFINITY ROADMAP (TIMELINE) February 15, 2017
February 15, 2017
Ethereum based community seed round raises 4M Swiss francs (CHF)
The DFINITY Stiftung, a not-for-profit foundation entity based in Zug, Switzerland, raised the round. The foundation held $10M of assets as of April 2017.
February 8, 2018
Dfinity announces a $61M fundraising round led by Polychain Capital and Andreessen Horowitz
The round $61M round led by Polychain Capital and Andreessen Horowitz, along with an DFINITY Ecosystem Venture Fund which will be used to support projects developing on the DFINITY platform, and an Ethereum based raise in 2017 brings the total funding for the project over $100 million. This is the first cryptocurrency token that Andressen Horowitz has invested in, led by Chris Dixon.
August 2018
Dfinity raises a $102,000,000 venture round from Multicoin Capital, Village Global, Aspect Ventures, Andreessen Horowitz, Polychain Capital, Scalar Capital, Amino Capital and SV Angel.
January 23, 2020
Dfinity launches an open source platform aimed at the social networking giants
2.DFINITY TECHNOLOGY
Dfinity is building what it calls the internet computer, a decentralized technology spread across a network of independent data centers that allows software to run anywhere on the internet rather than in server farms that are increasingly controlled by large firms, such as Amazon Web Services or Google Cloud. This week Dfinity is releasing its software to third-party developers, who it hopes will start making the internet computer’s killer apps. It is planning a public release later this year.
At its core, the DFINITY consensus mechanism is a variation of the Proof of Stake (PoS) model, but offers an alternative to traditional Proof of Work (PoW) and delegated PoS (dPoS) networks. Threshold Relay intends to strike a balance between inefficiencies of decentralized PoW blockchains (generally characterized by slow block times) and the less robust game theory involved in vote delegation (as seen in dPoS blockchains). In DFINITY, a committee of “miners” is randomly selected to add a new block to the chain. An individual miner’s probability of being elected to the committee proposing and computing the next block (or blocks) is proportional to the number of dfinities the miner has staked on the network. Further, a “weight” is attributed to a DFINITY chain based on the ranks of the miners who propose blocks in the chain, and that weight is used to choose between competing chains (i.e. resolve chain forks).
A decentralized random beacon manages the random selection process of temporary block producers. This beacon is a Variable Random Function (VRF), which is a pseudo-random function that provides publicly verifiable proofs of its outputs’ correctness. A core component of the random beacon is the use of Boneh-Lynn-Shacham (BLS) signatures. By leveraging the BLS signature scheme, the DFINITY protocol ensures no actor in the network can determine the outcome of the next random assignment.
Dfinity is introducing a new standard, which it calls the internet computer protocol (ICP). These new rules let developers move software around the internet as well as data. All software needs computers to run on, but with ICP the computers could be anywhere. Instead of running on a dedicated server in Google Cloud, for example, the software would have no fixed physical address, moving between servers owned by independent data centers around the world. “Conceptually, it’s kind of running everywhere,” says Dfinity engineering manager Stanley Jones.
DFINITY also features a native programming language, called ActorScript (name may be subject to change), and a virtual machine for smart contract creation and execution. The new smart contract language is intended to simplify the management of application state for programmers via an orthogonal persistence environment (which means active programs are
not required to retrieve or save their state). All ActorScript contracts are eventually compiled down to WebAssembly instructions so the DFINITY virtual machine layer can execute the logic of applications running on the network. The advantage of using the WebAssembly standard is that all major browsers support it and a variety of programming languages can compile down to Wasm (not just ActorScript).
Dfinity is moving fast. Recently, Dfinity showed off a TikTok clone called CanCan. In January it demoed a LinkedIn-alike called LinkedUp. Neither app is being made public, but they make a convincing case that apps made for the internet computer can rival the real things.
2.1 DFINITY CORE APPLICATIONS
The DFINITY cloud has two core applications:
- Enabling the re-engineering of business: DFINITY ambitiously aims to facilitate the re-engineering of mass-market services (such as Web Search, Ridesharing Services, Messaging Services, Social Media, Supply Chain, etc) into open source businesses that leverage autonomous software and decentralised governance systems to operate and update themselves more efficiently.
- Enable the re-engineering of enterprise IT systems to reduce costs: DFINITY seeks to re-engineer enterprise IT systems to take advantage of the unique properties that blockchain computer networks provide.
At present, computation on blockchain-based computer networks is far more expensive than traditional, centralised solutions (Amazon Web Services, Microsoft Azure, Google Cloud Platform, etc). Despite increasing computational cost, DFINITY intends to lower net costs “by 90% or more” through reducing the human capital cost associated with sustaining and supporting these services.
Whilst conceptually similar to Ethereum, DFINITY employs original and new cryptography methods and protocols (crypto:3) at the network level, in concert with AI and network-fuelled systemic governance (Blockchain Nervous System — BNS) to facilitate Corporate adoption.
DFINITY recognises that different users value different properties and sees itself as more of a fully compatible extension of the Ethereum ecosystem rather than a competitor of the Ethereum network.
In the future, DFINITY hopes that much of their “new crypto might be used within the Ethereum network and are also working hard on shared technology components.”
As the DFINITY project develops over time, the DFINITY Stiftung foundation intends to steadily increase the BNS’ decision-making responsibilities over time, eventually resulting in the dissolution of its own involvement entirely, once the BNS is sufficiently sophisticated.
DFINITY consensus mechanism is a heavily optimized proof of stake (PoS) model. It places a strong emphasis on transaction finality through implementing a Threshold Relay technique in conjunction with the BLS signature scheme and a notarization method to address many of the problems associated with PoS consensus.
2.2 THRESHOLD RELAY
As a public cloud computing resource, DFINITY targets business applications by substantially reducing cloud computing costs for IT systems. They aim to achieve this with a highly scalable and powerful network with potentially unlimited capacity. The DFINITY platform is chalk full of innovative designs and features like their Blockchain Nervous System (BNS) for algorithmic governance.
One of the primary components of the platform is its novel Threshold Relay Consensus model from which randomness is produced, driving the other systems that the network depends on to operate effectively. The consensus system was first designed for a permissioned participation model but can be paired with any method of Sybil resistance for an open participation model.
“The Threshold Relay is the mechanism by which Dfinity randomly samples replicas into groups, sets the groups (committees) up for threshold operation, chooses the current committee, and relays from one committee to the next is called the threshold relay.”
Threshold Relay consists of four layers (As mentioned previously):
- Notary layer, which provides fast finality guarantees to clients and external observers and eliminates nothing-at-stake and selfish mining attacks, providing Sybil attack resistance.
- Blockchain layer that builds a blockchain from validated transactions via the Probabilistic Slot Protocol driven by the random beacon.
- Random beacon, which as previously covered, provides the source of randomness for all higher layers like the blockchain layer smart contract applications.
- Identity layer that provides a registry of all clients.
2.2.1 HOW DOES THRESHOLD RELAY WORK?
Threshold Relay produces an endogenous random beacon, and each new value defines random group(s) of clients that may independently try and form into a “threshold group”. The composition of each group is entirely random such that they can intersect and clients can be presented in multiple groups. In DFINITY, each group is comprised of 400 members. When a group is defined, the members attempt to set up a BLS threshold signature system using a distributed key generation protocol. If they are successful within some fixed number of blocks, they then register the public key (“identity”) created for their group on the global blockchain using a special transaction, such that it will become part of the set of active groups in a following “epoch”. The network begins at “genesis” with some number of predefined groups, one of which is nominated to create a signature on some default value. Such signatures are random values — if they were not then the group’s signatures on messages would be predictable and the threshold signature system insecure — and each random value produced thus is used to select a random successor group. This next group then signs the previous random value to produce a new random value and select another group, relaying between groups ad infinitum and producing a sequence of random values.
In a cryptographic threshold signature system a group can produce a signature on a message upon the cooperation of some minimum threshold of its members, which is set to 51% in the DFINITY network. To produce the threshold signature, group members sign the message
individually (here the preceding group’s threshold signature) creating individual “signature shares” that are then broadcast to other group members. The group threshold signature can be constructed upon combination of a sufficient threshold of signature shares. So for example, if the group size is 400, if the threshold is set at 201 any client that collects that many shares will be able to construct the group’s signature on the message. Other group members can validate each signature share, and any client using the group’s public key can validate the single group threshold signature produced by combining them. The magic of the BLS scheme is that it is “unique and deterministic” meaning that from whatever subset of group members the required number of signature shares are collected, the single threshold signature created is always the same and only a single correct value is possible.
Consequently, the sequence of random values produced is entirely deterministic and unmanipulable, and signatures generated by relaying between groups produces a Verifiable Random Function, or VRF. Although the sequence of random values is pre-determined given some set of participating groups, each new random value can only be produced upon the minimal agreement of a threshold of the current group. Conversely, in order for relaying to stall because a random number was not produced, the number of correct processes must be below the threshold. Thresholds are configured so that this is extremely unlikely. For example, if the group size is set to 400, and the threshold is 201, 200 or more of the processes must become faulty to prevent production. If there are 10,000 processes in the network, of which 3,000 are faulty, the probability this will occur is less than 10e-17.
2.3 DFINITY TOKEN
The DFINITY blockchain also supports a native token, called dfinities (DFN), which perform multiple roles within the network, including:
- Fuel for deploying and running smart contracts.
- Security deposits (i.e. staking) that enable participation in the BNS governance system.
- Security deposits that allow client software or private DFINITY cloud networks to connect to the public network.
Although dfinities will end up being assigned a value by the market, the DFINITY team does not intend for DFN to act as a currency. Instead, the project has envisioned PHI, a “next-generation” crypto-fiat scheme, to act as a stable medium of exchange within the DFINITY ecosystem.
Neuron operators can earn Dfinities by participating in network-wide votes, which could be concerning protocol upgrades, a new economic policy, etc. DFN rewards for participating in the governance system are proportional to the number of tokens staked inside a neuron.
2.4 SCALABILITY
DFINITY is constantly developing with a structure that separates consensus, validation, and storage into separate layers. The storage layer is divided into multiple strings, each of which is responsible for processing transactions that occur in the fragment state. The verification layer is responsible for combining hashes of all fragments in a Merkle-like structure that results in a global state fractionation that is stored in blocks in the top-level chain.
2.5 DFINITY CONSENSUS ALGORITHM
The single most important aspect of the user experience is certainly the time required before a transaction becomes final. This is not solved by a short block time alone — Dfinity’s team also had to reduce the number of confirmations required to a small constant. DFINITY moreover had to provide a provably secure proof-of-stake algorithm that scales to millions of active participants without compromising any bit on decentralization.
Dfinity soon realized that the key to scalability lay in having an unmanipulable source of randomness available. Hence they built a scalable decentralized random beacon, based on what they call the Threshold Relay technique, right into the foundation of the protocol. This strong foundation drives a scalable and fast consensus layer: On top of the beacon runs a blockchain which utilizes notarization by threshold groups to achieve near-instant finality. Details can be found in the overview paper that we are releasing today.
The roots of the DFINITY consensus mechanism date back to 2014 when thair Chief Scientist, Dominic Williams, started to look for more efficient ways to drive large consensus networks. Since then, much research has gone into the protocol and it took several iterations to reach its current design.
For any practical consensus system the difficulty lies in navigating the tight terrain that one is given between the boundaries imposed by theoretical impossibility-results and practical performance limitations.
The first key milestone was the novel Threshold Relay technique for decentralized, deterministic randomness, which is made possible by certain unique characteristics of the BLS signature system. The next breakthrough was the notarization technique, which allows DFINITY consensus to solve the traditional problems that come with proof-of-stake systems. Getting the security proofs sound was the final step before publication.
DFINITY consensus has made the proper trade-offs between the practical side (realistic threat models and security assumptions) and the theoretical side (provable security). Out came a flexible, tunable algorithm, which we expect will establish itself as the best performing proof-of-stake algorithm. In particular, having the built-in random beacon will prove to be indispensable when building out sharding and scalable validation techniques.
2.6 LINKEDUP
The startup has rather cheekily called this “an open version of LinkedIn,” the Microsoft-owned social network for professionals. Unlike LinkedIn, LinkedUp, which runs on any browser, is not owned or controlled by a corporate entity.
LinkedUp is built on Dfinity’s so-called Internet Computer, its name for the platform it is building to distribute the next generation of software and open internet services.
The software is hosted directly on the internet on a Switzerland-based independent data center, but in the concept of the Internet Computer, it could be hosted at your house or mine. The compute power to run the application LinkedUp, in this case — is coming not from Amazon AWS, Google Cloud or Microsoft Azure, but is instead based on the distributed architecture that Dfinity is building.
Specifically, Dfinity notes that when enterprises and developers run their web apps and enterprise systems on the Internet Computer, the content is decentralized across a minimum of four or a maximum of an unlimited number of nodes in Dfinity’s global network of independent data centers.
Dfinity is an open source for LinkedUp to developers for creating other types of open internet services on the architecture it has built.
“Open Social Network for Professional Profiles” suggests that on Dfinity model one can create “Open WhatsApp”, “Open eBay”, “Open Salesforce” or “Open Facebook”.
The tools include a Canister Software Developer Kit and a simple programming language called Motoko that is optimized for Dfinity’s Internet Computer.
“The Internet Computer is conceived as an alternative to the $3.8 trillion legacy IT stack, and empowers the next generation of developers to build a new breed of tamper-proof enterprise software systems and open internet services. We are democratizing software development,” Williams said. “The Bronze release of the Internet Computer provides developers and enterprises a glimpse into the infinite possibilities of building on the Internet Computer — which also reflects the strength of the Dfinity team we have built so far.”
Dfinity says its “Internet Computer Protocol” allows for a new type of software called autonomous software, which can guarantee permanent APIs that cannot be revoked. When all these open internet services (e.g. open versions of WhatsApp, Facebook, eBay, Salesforce, etc.) are combined with other open software and services it creates “mutual network effects” where everyone benefits.
On 1 November, DFINITY has released 13 new public versions of the SDK, to our second major milestone [at WEF Davos] of demoing a decentralized web app called LinkedUp on the Internet Computer. Subsequent milestones towards the public launch of the Internet Computer will involve:
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On boarding a global network of independent data centers.
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Fully tested economic system.
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Fully tested Network Nervous Systems for configuration and upgrades
2.7 WHAT IS MOTOKO?
Motoko is a new software language being developed by the DFINITY Foundation, with an accompanying SDK, that is designed to help the broadest possible audience of developers create reliable and maintainable websites, enterprise systems and internet services on the Internet Computer with ease. By developing the Motoko language, the DFINITY Foundation will ensure that a language that is highly optimized for the new environment is available. However, the Internet Computer can support any number of different software frameworks, and the DFINITY Foundation is also working on SDKs that support the Rust and C languages. Eventually, it is expected there will be many different SDKs that target the Internet Computer.
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