This knowledge base is for developers, node operators, and those who want to learn more about the Radix project and distributed ledger technology.
Daniel Hughes, founder & CTO of Radix DLT invented the Radix platform and ‘Tempo’ - it’s underlying engine comprised of the consensus algorithm and data architecture.
In 2011, he discovered Bitcoin and was instantly hooked by the underlying elegance of its decentralized protocol. As he dug deep, he quickly realized it's limitations and proposed various solutions on the Bitcoin Talk Forum, only to be met with criticism. Ultimately, he decided to build his own decentralized ledger that could scale to support mass market decentralized applications with millions of users simultaneously. This obsession with building a truly scalable distributed ledger led him to build and test various suitable consensus algorithms and data architectures like blockchains, block-trees, directed acyclic graphs (DAG) and state channels. Having tested their limits, he found they all had a fundamental inability to scale. So he dedicated his time developing a new architecture and consensus algorithm. Five years in R&D and after many iterations he eventually invented ‘Tempo’ - a novel distributed ledger architecture and consensus algorithm for decentralized systems, that is sharded to scale in an efficient, unbounded linear fashion. It uses vector clocks for generating a partial ordering of events in a distributed system to detect and prevent causality violations.
This system is both “asynchronous”, meaning there is no block time, and byzantine fault detective, meaning that it can detect and stop false transactions and double spends within a system that anyone can join.
Tempo does this by preserving the total order of events, allowing for the trustless transfer of value, timestamping and other functionality. It is a semi-structured, shardable architecture that limits state transfer information to only those members of the network that need it. This reduces overhead and increases performance.
It does not require large amounts of computing power (PoW) or large amounts of capital (PoS) to secure it. It is suitable for both public and private deployments, without modification, and requires no special hardware or equipment.Combined with a huge, overlapping shard space, the scalability of Radix is only constrained by the number of Nodes operating within the network.
Radix is a new platform, like Bitcoin or Ethereum, but scalable and easy to build on. Instead of using blockchain, we started from scratch with a completely new design so that every person and device in the world could use the Radix ledger without centralization or compromise. We created building blocks for developers, making applications, tokens and coins as easy to deploy as possible. It’s fast, it works and our test net is already live.
It is a speedy alternative to blockchains and DAGs. It uses both the passage of logical time and database sharding to create an immensely secure and scalable system for the storage and accessing of immutable data and decentralized logic.
Decentralized Ledger Technology (DLT) offers a powerful new platform for the storage, verification and use of digital identity. One that is cryptographically strong, very difficult to hack and steal, and one in which the infrastructure it works on is antifragile; a term that means it is resilient even in the event of massive disruption.
Prior to the creation of Radix, the predominant technology for building and deploying DLT was blockchain, a technology that allows many computers to agree on a single version of events, without any centre to the system.
This is a powerful concept as there is no one place to attack or disrupt. It provides certainty of data integrity, and trust in the transactions conducted using it. But it has a major drawback - it does not scale very well.
This has not been a major problem for the relatively niche use cases that it has been used for so far. However as the applications that can be built using the technology have broadened, the technical limitations have become clear. Specifically the block size limit, which means the maximum throughput a blockchain can cope with is around 500 transactions per second. If you compare that to Visa, which is 2,000 transactions per second, blockchain is clearly not ready for mainstream applications.
Limitations of current decentralized ledgers:-
They cannot scale to meet demand
Consensus is inefficient and resource intensive
Networks are prone to miner centralization
Smart Contracts are complex and expensive to use
Volatile crypto currencies cannot be used as cash
The Radix ledger eliminates all of these limitations.
It has been the result of 6 years of research and development into a number of unsolved computer science problems. It is a decentralized ledger which is redundantly replicated but without the drawbacks of inefficient uses of large amount of power, and blockchain’s inability to scale to millions of simultaneous users, without significant compromise or centralizing.
For a decentralized protocol to be mass adopted, it should be designed to be fast, scalable, efficient and secure, but without compromising on security or decentralization. It is also critical to incentivize network participants with a low volatile crypto currency that eventually becomes stable and thus usable as a peer-to-peer version of electronic cash originally envisioned by Satoshi Nakamoto. Finally, it is crucial to build a developer friendly platform that everyone can build on.
To achieve this, Radix created 'Tempo' a combined distributed ledger architecture and consensus algorithm that is massively sharded to scale to 7 billion people and 30 billion devices simultaneously.
Radix is both asynchronous byzantine fault tolerant (aBFT) to guard against 51% network split attacks and asynchronous byzantine fault detective (aBFD) to detect malicious activity even with 99% bad actors in a system (or on a shard). It does this using the theory of sharding and the passage of logical time.
Radix is built on a combined architecture and consensus algorithm called Tempo, which is fully outlined in the Tempo white paper that can be found here: http://bit.ly/2ADK8LA
The aim of Tempo is to create a secure and reliable consensus on a decentralized public ledger. To do this it must be:
Asynchronous - any process on the network can start or end whenever it needs to - e.g. it does not need to wait for a “block” to be mined.
Highly concurrent - many processes can be done simultaneously, without bottlenecks - e.g. there is not a limit to the number of transactions that can be fit into a “block”
Scalable - there is not an upper limit restricting the total throughput of the network, such as the limits CAP Theorem puts on Blockchains and DAGs.
To achieve this, Tempo relies on a two simple ideas, and one logical leap:
The use of a basic digital clock called a “logical clock”
Telling your neighbors what has been happening, a process called “Gossip”
To stop double spends across shards, your shard address should be based on your wallet public key
A logical clock is a counter that is incremented by 1 every time something new happens. On Radix, “something new” is when one Node speaks to another in the Radix network. This gives every Node their own relative time, based on network activity, and one they can use to create a simple order of events.
Gossip protocols are well established in computer science and are one of the fastest ways in which information can be reliably shared across a network. It works simply by a Node choosing a couple of other Nodes to tell something new to, and they, in turn, tell two other Nodes, and so on and so on. This causes information to spread at an exponential rate.
On Tempo, we add the Node logical clocks, signed by the Nodes in question, to the gossip they are spreading around the network. This allows everyone to see both new information, and at what logical clock time that information was seen by other members of the network.
To allow high scalability a Tempo ledger is split into a very large shard space, allowing a huge degree of concurrency. To avoid a double spend across any of the shards, the shard a wallet lives on is determined by its public key. This makes sure that any spend from a wallet will always start on the same shard.
When combined with the logical clocks and gossip, this Tempo to always find the total ordering of related events, allowing double spends to be quickly detected and ignored.
Radix is used by decentralized applications that demand fast transactions with near-instant finality. Mass market applications like payment networks, games, marketplaces, and exchanges are some examples.
Asynchronous, <5 seconds transaction finality time. Transactions settle as fast as fiat transactions.
Massive sharded to scale linearly with no upper bound - solves the trilemma of decentralization
Negligible transaction fees projected to cost up to 1¢
Secure algorithm that achieves consensus with even 99% malicious nodes on a shard
Reduces energy footprint by 98% as algorithm is not based on Proof of Work
Reduces the barrier to entry by making it simple to deploy a node
Node runs on standard commercial hardware
Avoids network centralization by not requiring high computing power or capital to secure the network
Does not discriminate low powered devices by enabling them to support the network partially as per their resource capacity and providing an equal chance of earning rewards.
Low Volatility Token (XRD) - enables a true cryptocurrency that protects consumers and merchants by dampening volatility and preserving long-term price value curve.
Private/Public Network deployments uses the same technology.
Constraints Machine allows for validating state transitions instead of computing them
Modular - allows for multiple layer constraints and development opportunities
Constraints - allows accounts and tokens to have multiple layers of permission sets on functions of account ownership, account recovery, send/receive tokens
API - allows for building most DLT use-cases without the use of smart contracts
All token types are first class citizens - allows paying for services without having XRD token via the decentralized exchange
Decentralized exchange for price discovery and allowing peer to peer trading of assets
Scrypto is a state machine which provides security and functional abstraction to virtual-machines that live on top of it. This enables any VM to interface (providing it can) and execute any script in any language.
It is an idiomatic, user friendly way which will allow anybody with little to no development experience to write their own DAPPs on the Radix distributed ledger.
The Decentralized Identifiers (DIDs) v0.11 specification defines a standard for a decentralized, self-sovereign identity layer on the internet that can be implemented by any DLT. It defines how identification is structured, how communications are established and permissioned. Radix is developing a decentralized identity solution based on these standards.
The Radix Name service will provide flexible resolution of short, human-readable names to service and resource identifiers.
A decentralized smart/debit card compatible with existing point-of-sale systems for enabling merchants to accept Radix assets faster and helping users spend them anywhere.
The Radix platform is now in our Alpha stage of development, with a live Alpha testnet that you can connect to and try building against. Find out more here:
And start building here: https://github.com/radixdlt/
All our libraries are open source. The core code is not as we have not yet launched the main net and are not doing an ICO. Since our Roadmap is still quite a long one, we have made the difficult decision not to open source immediately as we do not believe someone would not fork before we even get a chance to launch ourselves.
However, once launched, all the Radix code will absolutely be 100% open source. We believe that to build a platform for the world to build on, it must be an open one.
In the next section we discuss the design philosophy of 'Tempo' and how it works to enable a fast, scalable and simple DLT platform to build on.