
Overview of decentralized technologies. Part 1

Blockchain
Blockchains are a technology of distributed computing and general consensus of users created by the mysterious Satoshi Nakamoto. It lacks central management, and P2P networks, codifications, and cryptography are used to verify transactions. Moreover, transactions can be managed using programmable contracts. In the Bitcoin blockchain, any transactions are not considered legitimate (confirmed) until the information about them is grouped into special structures - blocks. The structure and information in the blocks obeys the given rules and can be quickly checked. Each block always contains information about one previous block. This allows you to build all existing blocks in one chain, which is a distributed database and contains information about all transactions ever made with bitcoin.
Bitcoin is the first and most successful application of blockchain technology, but there are many, many other cryptocurrencies known as altcoins. Moreover, there are many examples of how new blockchains are used not only for cryptocurrency purposes - Ethereum, Ripple and Storj.io, we will talk about them today in the first part of our series of articles on decentralized services. In light of recent events , the aim of the article is also to show that
Ethereum

Zug, a Swiss-based company, is developing a software platform that will use a network of computers similar to the Bitcoin network to decentralize any kind of economic activity. Developers will be encouraged to create software applications that purposefully use such a network and its transparent public register - “blockchain”, in order to get rid of intermediaries and reduce the cost of exchanging funds, assets and information between people or companies.
Among the ideas that have arisen, there is an Ethereum-based, decentralized, Facebook-like product where users will have full control over their personal pages, which will allow them to independently generate revenue from advertising, instead of sending them to a centralized company. Among other ideas: securities markets operating without a stock exchange or a clearing center, agreements for the implementation of which do not require the services of lawyers or tamper-resistant polling and polling platforms that carry out flawless vote counting without the participation of a sociological center or the processing of ballots by an electoral body .
This concept aroused great interest among techies, which may well explain the success of the pre-sale of ether - digital, coin-like title marks from Ethereum, which are characterized on its website as the "fuel" necessary for applications to work on this platform.

The issue of these signs, not secured by any rights or profits from ownership, has not yet begun, but the campaign for their pre-sale in unlimited quantities has already passed, in accordance with the sliding tariff scale, where the prices are indicated in Bitcoin. Ultimately, more than 60 million units of currency were sold. As part of the first round, which lasted two weeks, a price of 2000 ethers for bitcoin was set. Further, the value decreased by 30 units until the very end of sales. Total sales exceed almost all such fundraising campaigns on popular crowdfunding sites such as Kickstarter and amount to more than $ 14 million.
According to information from one of the founders of Ethereum, Joseph Lubin, early orders came from software developers and financial institutions who plan to develop their applications on the basis of Ethereum, as well as from buyers who relied on the demand for signs in the future.
According to Swiss law, pre-sale is not considered a public issue of securities or currency, but is regarded as a release of the product. That is, ether is considered as a form of software, on the basis that developers will need title characters to implement their software applications.
Mr. Lubin said third-party developers are currently creating “hundreds” of promising applications based on the Ethereum platform, including digital currency exchanges, digital wallets, decentralized messaging programs, reputation-based trading floors and self-regulatory “smart legal contracts”.
Ethereum is the embodiment of the idea of Vitalik Buterin, who created a draft version of the technical documentation of the project last year, at the age of 19 years. Buterin’s idea was modeled on the core of the Bitcoin infrastructure, the decentralized network of which, together with the blockchain register, eliminates the need to work with “trusted” third-party intermediaries, such as banks, between individuals.
However, Mr. Buterin considered that the Bitcoin infrastructure is too limited to support the whole variety of applications that these projects can offer, so he came up with Ethereum, which offers a completely new, independent blockchain and its network of miners.

Ethereum is now available in beta. With it, you can create an application or release your own cryptocurrency - according to Buterin, this requires minimal programming skills. A full working version will be released later this year. You can already find videos on YouTube where the first developers for Ethereum show how to write code for their applications with it.
Repository - github.com/ethereum
Ripple

called ripples (XRP). The Ripple network aims to make it possible to conduct “safe, instant and maximum free financial transactions of any amount without recalling all over the world.” It supports working with any fiat currencies (dollars, yen, etc.), cryptocurrencies (bitcoin, litecoin, etc. .), goods or other units of value (miles of air travel, minutes of conversation over cellular communications, etc.).
At the heart of Ripple is a collective and open database - register. In addition to data on the balance sheet, the register contains information on offers to buy or sell foreign currency or assets, thus forming the world's first distributed exchange. Network members agree to the changes made to the register through a process called consensus, which occurs every 2-5 seconds. “Consensus” allows you to make payments, exchanges and transfers without the need for a single clearing center. Compared to cryptocurrencies such as Bitcoin, where security is ensured by the mining process, maintaining a register based on “consensus” allows the Ripple network to withstand any attacks steadily and while maintaining the effective operation of the system.
In the Ripple system, users make payments between themselves using cryptographically signed transactions expressed either in Ripple's internal currency, XRP, or in other arbitrarily selected assets (including real assets such as dollars, gold, flight miles, etc.). For transactions expressed in XRP, Ripple can use its internal register. For payments denominated in any other assets, the Ripple register only records the number of units that one user has lent to another. Thus, all such assets are presented as debt. This approach requires trust, as Ripple only keeps records in a register and has no regulatory power in the real world. Users must determine which participants they trust and quantify this trust.

When two users who trust each other make a non-XRP payment, their mutual credit balance is adjusted. Payments are made subject to user-defined limits. In order to send assets between users who have not established trusting relationships with each other, the system tries to find a path between them, each gap of which would be a pair of participants trusting each other. In the event of such a transaction, all balances are adjusted simultaneously as a whole. This mechanism for making payments through a network of trusted participants is called “rippling”. It is a digital version of the hawala settlement system that has existed since ancient times and is also called “Facebook for money”.
When processing each transaction on the Ripple network, 0.00001 XRP is deducted (approximately one
hundred thousandth cent in dollar terms). This is not a commission charged for anyone else's benefit, XRP is debited and ceases to exist. A similar transaction fee is also set in a very small amount for users. But when the network is under heavy load, for example, when it is attacked, the size of this commission increases rapidly. The purpose of such a network device is to quickly bankrupt attackers and ensure the smooth operation of the network. Attacking a Ripple network can be very expensive in a very short time, but for ordinary users it essentially remains “free.”
The creator of Ripple is Ripple Labs. Since the Ripple network is based on free and open source code, the development company does not receive revenue from the use of the network. Ripple Labs hopes to make money on XRP if the world becomes convinced that the Ripple network is useful and accepts the protocol en masse.
With the creation of the Ripple protocol, 100 billion XRPs were released. Ripple Labs plans to provide 55 billion XRPs to charities, users, and ecosystem ecosystem strategic partners over time. The company will retain part of XRP with the hope of creating a reliable and liquid market with the goal of monetizing its only asset sometime in the future.
Ripple ruble gateway - rippleru.com
Introductory course on Ripple in Russian -ripple.com/ripple_primer_ru.pdf
Repositories - dev.ripple.com
Storj.io

Each interested participant in the system can, for a fee, expressed in SJCX, use the storage and put their data there. Access to this component of the platform is through Metadisk- A web client created specifically for user interaction with the repository.
Users can also participate in the work of the system as owners of nodes, giving free space on their disk and bandwidth to the Internet channel using the special DriveShare client, which will be available for Windows, Linux and Mac. In exchange for this, owners of DriveShare nodes will earn SJCX or other cryptocurrency.
The developers of the platform are convinced that the emergence of such a system will create competition for centralized cloud storage, such as Amazon S3 or Dropbox. In the project blog, they provide an analysisDropbox pricing policy, concluding that its users pay monthly or annually for the possibility of using a certain fixed amount of storage, while often overpaying for gigabytes of data that they actually do not use. Dropbox pricing consists of the costs of using third-party servers (Amazon), maintaining infrastructure, renting premises, paying salaries to employees and profit to investors.

The cost of 100% storage utilization of 100 GB in size for 1 year.
Dark blue shows storage costs, blue - the cost of extracting all stored data from Metadisk.
The cost of using Storj, on the contrary, is made up of objective factors: it is assumed that the user pays only for the actually used space, the cost of which is determined by the "provider" Storj, for which Ordinary owners of nodes who provide the space of their disks for use will speak. However, who will set tariffs and how exactly pricing will take place among a huge number of nodes throughout the system is currently unknown.
According to the developers, the cost of the service will fall by dozens, or even hundreds of times, making it much cheaper compared to classic centralized competitors. Data is provided according to which the owner of a PC node, with an average Internet access speed of 2.1 Mbps and using Dropbox's pricing policy, will be able to earn about $ 150 per month.

Safe decentralized storage according to Storj version.
Security and anonymity of the service are guaranteed by the elimination of intermediaries (decentralization), as well as the use of encryption to protect data during transmission through communication channels. At the same time, the authors of the project strongly oppose the possibility of seizing or copying user data at the request of law enforcement agencies or manual intervention in the operation of the system if the user violates the rules of the user agreement. The concept of Storj implies the complete autonomy and non-interference of any human intermediaries in resolving conflict situations.
Storj developers claim that in addition to using the public Bitcoin register, the system will inherit its public and private key encryption mechanism and the use of cryptographic hash functions.
The project publicly announced itself in March this year at the Bitcoin Hackaton Conference in Texas, receiving a winner’s award there. The developers spent a crowd buyback of 500 million SJCX, which however was unsuccessful: Storj was unable to gain even 10% of the desired amount of 9800 BTC.
Such a weak result is explained by the distrust of the community, based on the almost complete absence of any technical information. The Storj team did not provide any specific platform specification. The only technical document available todaylooks more like an advertising presentation of Metadisk and contains general information, criticism of traditional cloud services, the theoretical concept of Metadisk, but does not answer questions about how the system works at the level of program code and does not provide details about the operation algorithms and technologies used.
A team of 16 people works on Storj, the names and photos of which, together with data on their role in the project, are published on a special page on the official website. The source code for the various Metadisk and Storj modules is available in the Storj github repository.. In fact, work on Storj is at the concept development stage: the written software components are not even ready for full testing, not to mention the launch of the service. Everything that is available for study now is an idea, supported by code sketches.
In order to achieve a successful project, the Storj team will have to answer many questions. How to provide protection against malicious attacks (for example, Sybil attacks) or the operation of a large number of system nodes in one person? How to satisfy the growing demand for storage volumes if it is successful, without resorting to centralized providers? How to deal with the distribution of prohibited content, using the service for terrorist purposes or for money laundering, taking into account a policy of complete anonymity and non-interference?
Storj is not the first project aimed at implementing the idea of a decentralized, secure and anonymous cloud storage that allows you to run full-fledged web applications on its basis. To one degree or another, he is a competitor to Ethereum, Maidsafe, Permacoin and some other projects that are also working on this promising idea, but have not yet achieved its full implementation.
Repository - github.com/Storj
Conclusion
In this article we examined only a small part of interesting decentralized services that are currently being actively developed, in the next part we will consider other equally interesting new services and technologies that are so poorly covered on the Russian-speaking Internet.
The second part - geektimes.ru/post/241426