The concept of a new generation of cryptocurrencies that are missing miners and transaction fees, and do networks have a highly scalable (at least theoretically), is rapidly gaining popularity. While such networks a bit, and the minimum operating level was not achieved in IOTA
(token XRB), although competitors and various clones are already starting to appear in development is a pretty interesting concept Radix, and the structure of the Tangle underlying IOTA, developing a project Spectre, who is still at the stage of theoretical developments.
Despite the external similarity, their principles of operation differ considerably. In General, the concept of fast and free cryptocurrency network is incredibly attractive, even though the already working network still are at an early and experimental stage of development, and their future does not seem clear. For example, one of the key developers of the Ethereum Foundation, Nick Johnson (Nick Johnson), back in September highlighted the vulnerability of the IOTA Protocol, the decisions of which have not been found so far.
How these network
In order to send the transaction to the network IOTA, the sender needs with easy PoW algorithm confirm the two previous transactions of arbitrary senders. Calculate PoW take from several seconds to several minutes, depending on the GPU (algorithm PoW in IOTA is optimized for GPU) and some luck. Once the decision PoW received, the data of the sender transmitted to the network and are awaiting confirmation from the following transactions. As soon as the transaction to get sufficient confirmations from other senders, it is confirmed.
In theory, the more network transactions, the sooner they can be confirmed. In the early stages of the development of IOTA it was, however, now, network congestion cause various kinds of delays. There is some controversy, because the marketing service IOTA constantly emphasize its «infinite scalability». The problem lies in the imperfection of the codes of the nodes. Updates code components and purses on December 23, has brought considerable relief to the users.
A significant increase in productivity can bring porting code from Java nodes to Rust or other high-level programming language. Java is a simple and common object-oriented language, however, his code should run on the JVM (virtual machine, allowing the migration of any computer system), which is bad for performance.
Architecture Raiblocks called «lattice units». This is not a one-dimensional blockchain, like Bitcoin or Ethereum; rather, it is a database in which each user (or address) gets its own blockchain. User sends funds, creating two blocks: (a) block the sender on its own blockchain; and (b) the unit of the recipient on the recipient blockchain. To obtain tokens, the user does not have to be online (early versions Raiblocks). As soon as the user opens access to their funds, the wallet automatically «puts it in his pocket» (pocket) all funds received. This procedure effectively means signing unit of the recipient with his private key, which finally adds it to a personal blockchain to the recipient.
The algorithm of consensus
In IOTA, the transaction is added to the structure of the Tangle, which is a directed acyclic graph (DAG). Complicated name, in practice, means a data structure that guarantees the absence of loops, i.e., starting from one node, it is impossible to return to it again. As soon as a greater number of transactions added to the Tangle, the «weight» of the parent transaction. When a transaction is gaining enough weight, she acquires the status of confirmed.
In Raiblocks uses a system of evidence-based confidence «to» addresses with large balances that serve as the arbitrators when choosing between conflicting units and prevent double-spending. Despite the fact that extensive examinations on the basis of game theory have not been conducted, it can be assumed that in this system, similar to the kind delikatesnogo PoS is a serious security vulnerability in such system in their current performance usually have a tendency to the formation of oligopoly, where the whole system is controlled by a small group of «whales,» which possess the maximum token balance.
Motivation to support the network
The most common question that arises when discussing networks that do not charge commissions: «Who pays for the maintenance of full nodes on the network»? In the traditional cryptocurrencies, such as Bitcoin or Ethereum, miners have sufficient motivation in order to maintain full nodes, because they get the reward; however, in IOTA and Raiblocks miners do not exist. A comprehensive answer to this question yet. Currently, developers and cryptocurrency exchanges contain full nodes. Even if we assume that each exchange has 5 nodes (it is a little, because you need to consider the balance sheets, and carry out upgrades), and both systems have already managed to gain popularity, some 100 exchanges around the world give 500 nodes.
In addition, nodes contain commercial companies that provide services to the IoT as the Internet of Things is still the most attractive place of application systems supporting micropayments. Forbes believes that by 2025, the number of IoT devices will exceed 75 billion. Even if 0.001% of these devices for any reason will maintain full nodes, they will have 750 thousand.
A unique feature of IOTA – create the transaction offline (offcam), and attach them to Tangle later, at a convenient time, i.e., the system has a high resistance to separation. IoT devices can interact with each other while offline and transfer the entire batch of transactions after connecting to the network. However, this feature is also a weak point: believe it or not the recipient that is not a transaction double-spending, without confirmation of all nodes in the network? So while the usefulness of this feature remains questionable.
In Raiblocks ofcan transactions impossible. For the transaction, the sender must be online.
The number of coins in circulation
Tokens as IOTA and Raiblocks fully generated preminum the number of coins set at startup of the network and the additional issues will be.
In circulation is about 2.8 quadrillion coins IOTA (for comparison, the maximum number of Satoshi in Bitcoin is about 2.1 quadrillion). For simplicity, the exchange would prefer to nominate coins in million IOTA – MIOTA.
The minimal unit Raiblocks raw (similar to Satoshi). The total number of raw is 2 to 128 degrees (the reason for such a high ceiling that the balance is represented as a 128-bit integer. 1 token XRB contains 10 to 30 degrees raw, then the total number XRB can be written as 133 248 290 XRB.
Robust decentralization is the weak point of both systems.
IOTA is constantly under fire for the existence of an element called «Coordinator», which has full authority and is under the control of the developers, which, however, promise to remove it from the system in 2018.
Another problem with IOTA – peering. Until recently, operators of the nodes had to manually add the IP addresses of other nodes in their configuration, but the latest developments should solve the issue.
Raiblocks based on a system of delegative PoS, a certain tendency to centralization. However, DpoS Raiblocks different from the traditional, and the developers claim that for a successful attack, the attacker must concentrate more than 50% of the token system, but an independent examination has not been undertaken.
Both systems have entered a period of intensive development. At the moment, the IOTA team consists of 30 developers. Team Raiblocks less – there is only 5 people.
And different purposes: while IOTA announces more and more new products (private transactions, smart contracts, markets), Raiblocks prefers to focus on the mantra «Do one thing, but doing it well» and aims to create the best coin with free transactions.
A key element of any cryptocurrency platform wallet. Here, both networks are similar in their wallets are extremely inconvenient interface, and the action sequences seem designed to serve to confuse users. However, this can be attributed to the initial period of development.
IOTA and Raiblocks, being completely different in structure, however, definitely have common application area.
Each team has its own vision of the future, and it is impossible to say whether there will be one winner or each project will find its niche. In any case, the emergence of a «perfect» coins at the least, unlikely. However, now it is equally impossible to say anything definite about whether it is possible to create robust cryptocurrency with unlimited scalability and the lack of transaction fees.