Currently, users of Bitcoin and other non-privacy coins are using mixing services. However, even for non-custodial services there are many risks, caused by dropping on networking traffic, adversarial partners or even mixing service.

As a solution, non-interactive mixer comes. In this case Alice just puts her coin on the blockchain and waits for Bob. Coin's contract allows Bob to spend Alice's coin as well as Bob's coin but only if two outputs of the transactions would be properly mixed and indistinguishable for external observer.

A paper on such a mixer (with my co-authorship) appeared online recently https://eprint.iacr.org/2020/560 , but for Ergo there's proof-of-concept mixer already (made ny anonymous dev "anon92048"): https://github.com/anon92048/ergo-mixer-web

For Bitcoin, a little bit similar scheme called SNICKER is coming, but currently in form of early draft. Also, it still requires for some offchain public bulletin board.

There are some wallets coming with such mixer built in, such as Cypra wallet: https://cypra.io/

Thus a gap between privacy and non-privacy coins become more narrow.

Please let me know what do you think on that.

Ergo is simple, solid and innovative cryptocurrency!

* While incorporating cutting-edge new ideas, Ergo’s foundation is a conservative Proof-of-Work cryptocurrency with limited supply. It aims to be as simple as Bitcoin wherever possible, though is not a Bitcoin fork but an entirely new cryptocurrency designed and implemented from scratch.

* Ergo has solid design specifications based on scientific research, drawing on a number of published academic papers (https://ergoplatform.org/en/documents/). At the same time, it also focuses on practical use cases. Ergo is designed and implemented by a team of experienced devs and researchers, with publications and PhDs in cryptography, compiler theory, blockchain technology, and cryptographic e-cash. The team also has a solid background in core development with such cryptocurrencies and blockchain frameworks as Nxt, Scorex and Waves.

* Ergo offers a series of innovations, including:
   - Extended UTXO model, offering the ability to write complex financial applications. Community members are currently implementing a DEX, and there are already applications for oracles and p2p crowdfunding, as well as example contracts for bonds, auctions, p2p interest-free loans, mutual credit systems, etc. 
   - Built-in support for complex signatures and cryptographic protocols via an efficient class of zero-knowledge proofs-of-knowledge (Sigma protocols). As an immediate result, ring,
threshold and composable signatures are easy to implement out-of-the-box. For applications, Ergo devs have already proposed a simple non-interactive mixing scheme called ErgoMix.
   - Custom token support at the core level (similar to RavenCoin).
   - Storage rent to stabilize mining income in the long term.
   - New Proof-of-Work scheme, Autolykos – a variant of Equihash with better ASIC-resistance and even a degree of pool-resistance.

Ergo is a community-driven project, with conversations occurring over Discord (https://discord.gg/uhr6cq), Telegram (https://t.me/ergoplatform) and the forum (https://www.ergoforum.org/).

To get Ergo, visit supporting exchanges (https://ergoplatform.org/en/exchanges/) or mine ERG with an NVidia or AMD GPU.

Please visit our welcoming and vibrant community to HODL and BUIDL together!

"While most active conversations today in the space are about wider adoption of the blockchain technology (which often means selling out to the Wall St.) and competition with systems like Visa and Mastercard (which often means giving up with decentralization or introducing unclear security assumptions in the name of efficiency), there is the obvious need to revisit the roots of the cryptocurrency movement, which are mostly about decentralization. Many questions to be answered in clear here. Is it okay when 90% of mining power in Bitcoin can gather in one room? Is it okay when 2 or 3 mining pools control majority of hashing power, so can do censorship? Is it okay when almost all the new nodes avoid processing a blockchain from its genesis block? Is it okay when a Proof-of-Work coin developers are doing a hard-fork changing the consensus algorithm to make it GPU-friendly again? Can we summarize all the issues with decentralization? Can we cover most of issues with technical means?"

With this motivation I've made an article on technical tools we can do for better decentralization (of PoW blockchains): https://ergoplatform.org/en/blog/2019_12_12_new_quest/ .

As a core developer and researcher, not a philosopher, I leave room for social aspects to others.

What do you think guys? How can we do better?

Ergo Mainnet Start war am 1.7.2019 (nachweislich ohne premine durch Einbeziehen der damaligen Bitcoin & Ethereum block hashes und der letzten Schlagzeilen aus The Guardian, Vedomosti und Xinhua)

Die Hauptkriterien im Überblick:
• Tiefgreifende Forschung und wissenschaftliche Herangehensweise: Ergo basiert auf origineller Forschung und wurde auf bekannten, peer-reviewten Konferenzen veröffentlicht. Die Liste der Veröffentlichungen ist unter  https://tinyurl.com/wleon3y verfügbar und geht über vorhandene Implementierungen von Use-cases über die Theorie weit hinaus.
• Programmierbares Geld: Die vorhandene Smart-Contract Platform hat eine neuartige, transaktionelle Sprache namens "ErgoScript" und wurde eigens dafür entwickelt. Zwei Tutorials sind auf der Webseite  https://ergoplatform.org/docs/ErgoScript.pdf und https://ergoplatform.org/docs/AdvancedErgoScriptTutorial.pdf vorhanden. Die Skriptsprache ist umfangreicher als Bitcoin ohne aber in Punkten Sicherheit Abzüge zu machen und ist schlank um Probleme wie Blockchain-Bloat im vorneherein auszuschließen. Während ErgoSkript nicht Turing-Vollständig ist, ermöglicht sie im Kontext der Plattform dennoch Turing-Vollständige Programme/Apps, wie der Veröffentlichung  https://arxiv.org/pdf/1806.10116v1.pdf gezeigt wurde.
• Der neue PoW Konsensus wurde in Kollaboration mit The Research Institute entworfen. Es ist der erste ASIC-resistente und Pool-resistente Konsensusalgorithmus der seine Anwendung findet (Mining pools sind damit nicht möglich und die Dezentralisierung sichergestellt). Technische Details zum Algo unter https://docs.ergoplatform.com/ErgoPow.pdf.
• Trustless Light Clients mit minimalen Ressourcen Anforderungen: Der Ergo Block Header unterstützt NiPoPoWs, welche es erlauben mit <1MB sich mit dem Netzwerk zu synchronisieren. Dies ist möglich da der Ergo State authentifiziert ist, wie aus diesem Paper 2017 bereits hervorgeht: https://eprint.iacr.org/2016/994.pdf.
• Neues Wirtschaftskonzept: Ein Schlüsselkonzept ist das Miner die Benutzer mit einer Gebühr belegen wenn die UTXO für mehr als 4! Jahre nicht bewegt wurde ("Zeitspeichergebühr"). Dies stellt einen stabilen Miner-Umsatz sicher (Miner ist letztendlich der User - da dezentralisierender Autolykos), unterbindet gefährlichen State Bloat und ermöglicht einen kurzen Emissionsplan: Die Ergo-Emission ist bereits vollständig nach 8 Jahren abgeschlossen. Details finden sich in  https://fc18.ifca.ai/bitcoin/papers/bitcoin18-final18.pdf.
• Dezentralisierung hat Priorität und ist ein zentraler Punkt von Team und der Community, wie auch unter "Ergo Vision" im Whitepaper festgehalten. Viele der genannten Eigenschaften sind ein Ziel dessen - Vires in numeri.
• Resilienz und Überlebensfähigkeit durch Dezentralisierung: Ergo wird durch seine netzartige Struktur indefinite überlebensfähig sein und die programmierbare Platform und deren Verträge überdauern mindestens eine Lebensspanne trotz sich ändernder, externaler Umgebungsbedingungen.
• 2+ Jahre Vollzeit Entwicklung: Seit über 2+ Jahren mit Anfängen in 2017 ist die Platform im Zuge der Ausgestaltung. Mit dem Mainnet-Start steht die Plattform für Entwickler, Miner und User bereits voll zur Verfügung.
• Des weiteren: Ergo ermöglicht es jedem seine eigenen nativen oder fremden Token auf der Plattform auszüschütten und dabei die Sicherheit und Dezentralisierung der Plattform zu genießen. Fortgeschrittene on-chain Verwaltung (governance) ist durch die Möglichkeit des Votings durch Miner gegeben um Parameter wie Blockgröße anzupassen (graduell in Schritten).

Ergo hat noch viel mehr zu bieten. Mehr, aktuelle Informationen und News findest du auf unseren Social Media Channels oder Frage einfach hier im Forum:

* Webseite: https://ergoplatform.org/
* Forum: https://www.ergoforum.org/
* Kurzer high-level Überblick (bündige 5 Seiten): https://docs.ergoplatform.com/teaser.pdf (Chinesisch: https://docs.ergoplatform.com/cn/teaser%E5%B0%94%E6%A0%BC%E5%B9%B3%E5%8F%B0%E7%AE%80%E4%BB%8B_%E4%B8%AD%E6%96%87%E7%89%88.pdf )
* Whitepaper I: https://ergoplatform.org/docs/whitepaper.pdf (Chinesisch: https://docs.ergoplatform.com/cn/whitepaper_cn.pdf )
* Twitter: @ergoplatformorg (https://twitter.com/ergoplatformorg)
* Telegram: https://t.me/ergoplatform
* Youtube: https://www.youtube.com/channel/UC7cht_rw6ofX3wTirrQG8kw
* Github: https://github.com/ergoplatform (weitere hochrelevante Links zu den Repositories finden sich auch auf unserer Webseite)
* Das Entwicklungs Team hat bereits 25+ Smart Contract Beispiele in ErgoScript bereit für den Einsatz: https://github.com/ScorexFoundation/sigmastate-interpreter/tree/master/sigmastate/src/test/scala/sigmastate/utxo/examples
* CUDA-basierter GPU Miner https://github.com/ergoplatform/Autolykos-GPU-miner
* AMD Miner https://github.com/mhssamadani/ergoAMDminer
* Russischer Thread: https://bitcointalk.org/index.php?topic=2170754
* Chinesische Telegram group: https://t.me/ergoplatform_CH

Wo gibt es Ergo zu kaufen und welche Wallets gibt es aktuell:

 * Exchanges: ProBit, Tidex, HotBit, Waves.Exchange, P2PB2B, Vite, GJ.com
 * Wallets: Magnum Wallet (Web), inbuilt into node (127.0.0.1:9053/panel)

Ergo Mainnet Launch happened on July, 1st, 2019 (with no premine proof made of latest block hashes from Bitcoin & Ethereum and latest headlines from The Guardian, Vedomosti and Xinhua).

What are the main points of Ergo?

• Rigorous research and scientific approach: Ergo is based on original research, published at known peer-reviewed conferences. List of scientific papers is available at https://apograf.io/c/7MEY3, but Ergo is not limited by research and it also implements other novel scientific ideas.
• Contractual money: a new advanced transactional language built from scratch by team, with a higher-level language for developers called “ErgoScript”. Two tutorials available on website: https://ergoplatform.org/docs/ErgoScript.pdf and https://ergoplatform.org/docs/AdvancedErgoScriptTutorial.pdf. It is more advanced scripting language than Bitcoin while maintaining security and not introducing blockchain bloat problems. Scripting language in itself is non-Turing complete but applications ran on the platform can be made to be Turing complete as demonstrated in this peer reviewed paper https://arxiv.org/pdf/1806.10116v1.pdf.
• New PoW consensus algorithm Autolykos, which was designed in collaboration with The Research Institute (https://researchinstitute.io/). It is the first ASIC-resistant and pool-resistant consensus algorithm to be deployed (mining pools won’t work in Ergo for sake of Decentralization!). Technical details in this paper: https://docs.ergoplatform.com/ErgoPow.pdf.
• Trustless Light Clients with Minimal Resource Requirements: Ergo block header supports NiPoPoWs that enable synchronizing network by downloading < 1Mb of data. This is further made possible by the fact Ergo state is authenticated as detailed in this paper from 2017: https://eprint.iacr.org/2016/994.pdf.
• New Economic Model: Key feature of the new model is miners charge users a fee for any UTXO that remains unmoved in state for 4 years (“storage rent fee”). This accomplishes stable mining revenue to secure network, prevents “state bloat” and enables a short release schedule – Ergo emission fully completes in just 8 years. Details in this paper: https://fc18.ifca.ai/bitcoin/papers/bitcoin18-final18.pdf.
• Mined from Zero via PoW with no ICO or Pre-mine. It is about a hope to achieve as fair distribution of Ergs as possible to enhance decentralization.
• Decentralization First: Core commitment of Development team and community. Top item in “Ergo Vision” section of white paper. Many of the above features’ main purpose is to achieve this goal.
• Resiliency and Survivability: Decentralization First is to accomplish this goal. Ergo should be alive and operational for an indefinite amount of time and Contractual Money contracts on Ergo should be able to survive for at least the length of a person’s life time despite a changing external environment.
• 2+ Years Full-time Development: Full-time development from scratch for 2+ years starting in 2017. Will launch as mainnet, ready for developers, miners and users to immediately start using Ergo.
• Other: Ergo offers anyone the ability to issue their own tokens (non-native tokens) on the platform and leverage off its security and decentralization. Advanced on-chain governance is built with miners being able to vote on a number of parameters including simple items like block size – gradual changes only to ensure stability.

The above is just a short summary. For more info, visit the website and ask questions here.

* Website: https://ergoplatform.org/

* Forum: https://www.ergoforum.org/

* Short high level intro (5 pages only): https://docs.ergoplatform.com/teaser.pdf (Chinese: https://docs.ergoplatform.com/cn/teaser%E5%B0%94%E6%A0%BC%E5%B9%B3%E5%8F%B0%E7%AE%80%E4%BB%8B_%E4%B8%AD%E6%96%87%E7%89%88.pdf )

* White Paper I: https://ergoplatform.org/docs/whitepaper.pdf (Chinese: https://docs.ergoplatform.com/cn/whitepaper_cn.pdf )

* Twitter: @ergoplatformorg (https://twitter.com/ergoplatformorg)

* Telegram: https://t.me/ergoplatform

* Youtube: https://www.youtube.com/channel/UC7cht_rw6ofX3wTirrQG8kw

* Github: https://github.com/ergoplatform (but important to note multiple other highly relevant Github Repository links can be found on website)

* Development Team already has 25+ Smart Contract Examples ready for Deployment by Developers: https://github.com/ScorexFoundation/sigmastate-interpreter/tree/master/sigmastate/src/test/scala/sigmastate/utxo/examples

* CUDA-based GPU miner https://github.com/ergoplatform/Autolykos-GPU-miner

* AMD miner https://github.com/mhssamadani/ergoAMDminer

* Russian thread: https://bitcointalk.org/index.php?topic=2170754

* Chinese Telegram group: https://t.me/ergoplatform_CH


How to get and store Ergo:

 * Exchanges: ProBit, Tidex, HotBit, Waves.Exchange, P2PB2B, Vite, GJ.com
 * Wallets: Magnum Wallet (Web), inbuilt into node (127.0.0.1:9053/panel)

After a long break from real systems development (only research and prototypes), I'm going back with a complete new design for a cryptocurrency / blockchain system.

Basic ideas:

- Lightweight non-mining full-node. Basic ideas and efficient authenticated dynamic dictionary implementation details are given in the paper https://eprint.iacr.org/2016/994.pdf, I also highly recommend this presentation by  Prof. Reyzin from RWC'17 https://www.youtube.com/watch?v=PHY7JnLrK5o
- For the mining nodes, it will be supposed that they are mostly running in the regime similar to Warp-mode in Parity, fast-mode in Geth, but stronger security guarantees, see this draft (more formal paper is on the way): https://arxiv.org/abs/1603.07926
- Instead of SPV, much more efficient light client regime, tens of kilobytes instead of tens/hundreds of megabytes to bootstrap! So really light mobile clients: Based on the work of Kiayias et al. http://fc16.ifca.ai/bitcoin/papers/KLS16.pdf

- New economic model, "space-scarce economy" https://eprint.iacr.org/2017/644

- New transactional language, superior to Bitcoin Script, for now only 1-page description is done and a prototype interpreter: https://github.com/ScorexFoundation/sigmastate-interpreter

It will be Proof-of-Work system, with some memory-hard Proof-of-Work to resist ASICs.


website is: https://ergoplatform.org/

development could be tracked on github: https://github.com/ergoplatform/ergo. The earliest testnet will be around in September, hopefully.

We made some free giveaway to Waves community, token is EFYT (Ergo First Year Token).

In the next chapters I will share details on the transactional language, as well as plans on governance, funding etc.

Please join the effort!

The idea that it is possible to get full-node security guarantees without holding the full state has been proposed before -- for example, by Bill White's paper "A Theory of Lightweight Cryptocurrency Ledgers" ( https://github.com/kushti/ledgertheory/blob/master/lightcrypto.pdf ), which the first one I know with this proposal.

Our contribution is developing this idea further and playing with possible authenticated dictionary designs to find a most efficient solution. We propose that only miners store a state (the UTXO set in case of Bitcoin) in RAM(we can assume miners can buy gigs/tens of gigs of RAM easily). They are providing proofs for state transformation correctness within transactions (or a batch proof within block). Other nodes are just verifying proofs. The verification process is fast(it is about just hashing) and consumes minimum RAM(no random disk IO as we have now with full state storing on commodity hardware e.g. 4GB RAM laptop where only 1GB could be given to a fullnode daemon). However, transactions are becoming bigger, so throughput is needed to be increased with some other proposal(there are a lot of them).

details are in the paper: https://eprint.iacr.org/2016/994 . would be happy to get feedback (please don't think it is a concrete proposal for Bitcoin though. We know that Bitcoin capabilities to upgrade are more than limited).

We are going to live in the post-DAO world, whether Ethereum will be (hard or soft)-forked or not.

One of the most important questions hasn’t been answered by the inner circle of Ethereum. And it is not being asked loud enough even. The question is what’s inside the Gordian knot of corrupt ties in the inner Circle.

Former Ethereum members founded Slock.it startup. Then the Slock.it team started The DAO venture, partly in order to get funding for Slock.it itself. The DAO was supported by many Ethereum core team members, including Vitalik.

As a result, a lot of tough question to be asked after the DAO crash. Would be (hard or soft)-fork proposed by Ethereum team if no Ethereum members participation in The DAO? Who are in the inner circle? What are the names of other projects to be saved with a fork in case of disaster?

Fortunately, I am not in the Ethereum world at all, so I do not know answers. Hopefully, some investigative journalists will dig there.

What’s interesting to me is how to avoid dubious scenarios in the future. I think we need to consider some moral ground for core developers and foundation members.

At least, it must be prohibited to work for a blockchain core and any for-profit project built on top of that at the same time, or even for some time after exiting working for a core.

Sometimes developers and foundation members are working for other projects because it is nearly impossible to pay bills developing a core product. For example, I left Nxt mostly because of pretty small rewards. For a developer with vast experience it is easy to find well-paid job. And core development requires highly skilled developers. So it is not easy to get away from multi-million ICOs. Highly-skilled developers team, security audits, consultations with academias and so on could not be cheaper than couple of USD millions. I don’t know about marketing, but I suspect it is not cheaper.

However, spendings must be transparent. Key meetings must be transparent as well, considerations behind key decisions should be described in details.

We need to re-consider governance models, again.

P.S. This post reflects my personal position only.

P.P.S. The title resembles “The Moral Character of Cryptographic Work” by P. Rogaway

A note: I worked for Nxt(core dev) in 2014 and now working on Scorex ( https://bitcointalk.org/index.php?topic=1103640 ).

Nxt core devs were sceptical about smart contracts inclusion into core. I myself was also sceptical about some things included into Nxt core  

Bitcoin developers switched off many opcodes for a reason ( http://bitcoin.stackexchange.com/questions/25225/what-was-the-vulnerability-in-v0-3-4-that-allowed-an-attacker-to-steal-coins ). Then Vitalik complicated security conundrum with its "Turing-complete" approach.

Now Ethereum guys are making the biggest error in their career going to do a hardfork, because not all the contracts are equal and some of them are too big to fail. There are some talks(copied from Bitcoin community) on "miners will decide", but it is unlikely miners will have any reasonable discussion. Instead, they will just follow the "digital Lenin".

It is time to go another path. The core must be as simple as that. But it also need to be powerful enough to support protocols and applications built outside the core.

There are many designs possible, and there are many open questions and concerns about them. Nevertheless, as the topic is going to be hot, I would like to propose one design in July or August (after Scorex 2.0 release).

From briefly observing Bitcoin/secp256k1 code of Schnorr sigs implementation, I've came to the conclusion it is assumed there multi-user Schnorr is about the same security as single-user. That was proven, but recently D. Bernstein did show the proof was incorrect, and multi-user Schnorr is provably secure only if key-prefixing. The paper is there: https://eprint.iacr.org/2015/996.pdf .

Please note absence of a provable security doesn't mean a practical attack exists. It could be found few years after though. Bitcoin devs please take care.

I am happy to propose an alternative Proof-of-Work consensus protocol. It is uploaded to Arxiv http://arxiv.org/abs/1603.07926 . Basically the idea reminds Permacoin but with archiving Merklized state snapshots collectively instead of a static dataset. I'm goingto copy the abstract below, but please read the paper before leaving a feedback ant please criticize it a lot in a constructive way!

Bitcoin is the first successful decentralized global digital cash system. Usefulness of the mining process requiring a lot of computational resources to be wasted, though, remains disputable. One of possible alternatives for useful Proof-of-Work schemes, Permacoin, is using non-interactive proofs of a static dataset retrievability thus providing a mechanism to store a huge dataset being spread across miners collectively.
In this paper we present a new consensus protocol for Bitcoin-like peer-to-peer systems, where the right to generate a block is given to the party which provides non-interactive proofs of retrievability for the past state snapshots. This Proof-of-Work scheme has better resistance to specialized hardware than Bitcoin and Permacoin. Unlike blockchain systems being used today, a network using the protocol of ours is safe if majority of nodes are rational in terms of storing full blocks. By using that we also show that one useful application of our protocol is the construction of a prunable blockchain system without a security loss.

A ledger in Bitcoin could be represented as unspent transaction outputs(UTXOs in Bitcoin jargon) list. Given a transaction it is easy to check whether it is valid: all the transaction inputs must be connected to unspent outputs, and also inputs must provide a valid solution(in form of stack machine script) to spending guard condition an UTXO has(in form of stack machine script as well). Also, sum of bitcoins associated with outputs must be no more than sum of bitcoins associated with inputs. Outputs spent are to be removed from ledger and new ones the transaction contains are to be added to it.

Abstracting the Bitcoin-like model, a state could be represented as a list of closed boxes. Each box has a value associated with it. A transaction contains keys to open some boxes and new closed boxes. A transaction is valid if all the keys in it are opening closed boxes in a ledger and sum of new closed box values is no more than sum of values of closed boxes to be open.

The question is, can we imagine an alternative solution(without a stack machine script) for a box? I cannot find anything really alternative.

Scorex is fully open (open-sourced under public domain license) modular blockchain framework: https://github.com/ScorexProject/Scorex .  Modular means you can swap a consensus or transactional part of a blockchain system or add a new p2p protocol as easy as possible. The project is supported by IOHK company (http://iohk.io/).

To prove that the framework is indeed modular we have implemented few modules: Proof-of-Stake consensus, Permacoin implementation, and simplest transactional module with just tokens transfers  from one pubkey to another(the only one kind of transactional modules unfortunately).

Permacoin is a consensus protocol based on non-interactive Proof-of-Retrievability scheme for a static dataset. Paper is made by Miller/Shi/Juels/Katz/Parno: http://cs.umd.edu/~amiller/permacoin.pdf .

We are launching first testnet release called Lagonaki. Lagonaki = Scorex + Permacoin + SimplestTransactions

Lagonaki Debian package and sources: https://github.com/ScorexProject/Lagonaki
Testnet seed node API is there: http://23.94.190.226:9081/

You can also run Lagonaki in a Docker(set wallet seed & wallet password in settings.json). Readme is in Scorex repository(you can temporarily run Lagonaki from there): https://github.com/ScorexProject/Scorex .

I'm filling wiki pages at the moment.

Please contribute by testing! We are also looking for contributors. In particular, it would be amazing to see Bitcoin and Ethereum-like transactional modules (possible by reusing BitcoinJ/EthereumJ code I guess). And please join developers maillist: https://groups.io/g/scorex-dev .

Few brightest minds in cryptography proposed how data archiving could be incentivized and used instead of Proof-of-Work via Proof-of-Retrievability   http://www.coindesk.com/cryptocurrency-mining-help-archive-societys-important-data/ (academic paper: http://cs.umd.edu/~amiller/permacoin.pdf ). Unfortunately, no open-sourced implementations of the Permacoin proposal are known to the moment.

To overcome this, Scorex devs(in partnership with IOHK) have implemented Permacoin implementation in the form of Scorex module. We have a plan to launch a public testnet in coming days.

Let's overcome IPOs fever and hack around blockchain for the sake of progress with Scorex! Attacks on consensus protocol are welcome.

Please join us by running nodes, attacking the consensus protocol, contributing to the code.

Maillist to be launched in next few days.

Github: https://github.com/ConsensusResearch/Scorex-Lagonaki



Acknowledgement: we would like to thank IOHK (new project of Charles Hoskinson et al, http://iohk.io/) for sponsorship, Andrew Miller for answering questions on Permacoin.

I would like to present a paper of mine on a new kind of pure Proof-of-Stake protocol, Interactive Proof-of-Stake. It is uploaded to Arxiv: http://arxiv.org/abs/1601.00275 . Simulation tools are on github https://github.com/kushti/common-pos .

I would like to got a feedback(heavy but constructive criticism is preferable). A next step is to develop hybrid PoW+IPoS consensus protocol, result will be like Bitcoin-NG, but with all the network(precisely, stakeholders) working on microblocks instead of a single miner.

Сабж. Готов поставлять битки, рублевые или долларовые BTC-e коды, и на постоянной основе тоже. За нал, север или центр СПб, или Курортный район. Пишите в личку

[Motivation]

Motivation

There are two huge problems around cryptocurrencies development project Scorex aims to help to solve:

* Bitcoin source code contains more 100K lines of code(80K of C++ only), Nxt is about more than 45K lines of Java code. All parts of the design(network/transactions/consensus layers) are mixed in a hard way.  So researchers & developers are definitely not in a good start position to make any experiments.  In opposite, Scorex is less than _4K lines of Scala code_. Transactions layer is as simple as just tokens transfers. Consensus algo  could be switched easily(with two consensus algos out of the box,  one could be replaced with an another with just one line of code edited!)

* Major coins forks are trying to make IPO immediately, often having just one or two pretty controversial features introduced. **Scorex is intentionally not production-ready**, so please participate in any  non-commercial experiments built on top of it, but don't buy tokens unless you are 100+% sure what are you doing.
 

Features

* Two 100% Proof-of-Stake consensus algos out of the box, Nxt-like and Qora-like. One algo could be replaced
with an another with just one line of code edited (in Constants.scala)
* Simplest transactions model
* Asynchronous network layer on top of TCP(with Akka I/O)
* JSON API
* Command line client for the JSON API
* Curve25519 for signatures
* CC0(Public Domain) license
* Compact, functional, actors-powered code
* Scala / Akka
 

Roadmap

This release is named Lagonaki (after picturesque mountains resort in West Caucasus https://yandex.ru/images/search?text=%D0%BB%D0%B0%D0%B3%D0%BE%D0%BD%D0%B0%D0%BA%D0%B8 ), the current version is 1.0. It is the initial release aiming to provide modular and simple product to improve.
     
There are some issues/todos to be solved in upcoming 1.1 then 1.2 versions.           
 
And new branch will be forked very soon, with a brand new Proof-of-Stake algo having no whitepaper atm. More details soon. Nxt forging algo improvement proposal will be derived then from testing results. 

Authors

Scorex is made by [Consensus Research microteam](https://github.com/ConsensusResearch) previously worked on Proof-of-Stake investigation:

Alexander Chepurnoy aka kushti - Nxt developer & smartcontract.com cofounder. Has few published papers in Computer Science field(finite state systems related), writing PHD at the moment.   

andruiman - serial entrepreneur with theoretical physics background, a big fan of Coq interactive theorem prover & functional programming.   


Contributions

We're highly welcome contributions in form of pull requests, testing, issues reporting, and forking for sure


Donations

Also we would be happy to get donations. You can buy our asset on Nxt Assets Exchange: https://trade.secureae.com/#5841059555983208287, Bitcoin wallet is **17YksFD7eRB4NhPfEtGrGnuvuwpkAeBd7f** .   
   


Repository URL

The main link to follow is the GitHub repository:

https://github.com/ConsensusResearch/Scorex-Lagonaki

 

[Motivation]

Motivation


There are two huge problems around cryptocurrencies development project Scorex aims to help to solve:

• Bitcoin source code contains more 100K lines of code(80K of C++ only), Nxt is about more than 45Kline of Java code. All parts of the design(network/transactions/consensus layers) are mixed in a hard way. So researchers & developers are definitely not in a good start position to make any experiments.In opposite, Scorex is less than 4K lines of Scala code. Transactions layer is as simple as just tokens transfers. Consensus algo could be switched easily (with two consensus algos out of the box,one could be replaced with an another with just one line of code edited!).
  
  
• Major coins forks are trying to make IPO immediately, often having just one or two pretty controversial features introduced. Scorex is intentionally not production-ready, so please participate in any non-commercial experiments built on top of it, but don’t buy tokens unless you are 100+% sure what are you doing.
  
  

Features

• Compact, functional, actors-powered code
• Two 100% Proof-of-Stake consensus algos out of the box, Nxt-like and Qora-like. One algo could be replaced with an another with just one line of code edited (in Constants.scala)
• Simplest transactions model
• Asynchronous network layer on top of TCP
• JSON API
• Command line client for the JSON API
• Curve25519 for signatures

Releases


There are two releases planned at the moment:

Lagonaki - initial release aiming to provide modular and simple product for hackers.

Kizhi - another branch in development with proof-of-stake consensus algo allows contribution to multiple branches following our papers, along with Nothing-at-Stake attack script etc.


Roadmap


Lagonaki release is mostly ready, there are about 30 todos in code to get done though. We’ll fix them within next few weeks. Some documentation will be written as well. At this point it will be an announcement(this message is the pre-announcement).

Then we’ll test Nxt forging algo improvements proposals with it(a proposal document will be published within next few weeks). And then we’ll work on Kizhi.


Authors


Scorex is made by Consensus Research microteam previously worked on Proof-of-Stake investigation:

Alexander Chepurnoy aka kushti - Nxt developer & smartcontract.com cofounder. Has few published papers in Computer Science field(finite state systems related), writing PHD at the moment.

andruiman - serial entrepreneur with theoretical physics background, big fan of Coq interactive theorem prover & functional programming.


Contributions


We’re highly welcome contributions in form of pull requests, testing, issues reporting, and forking for sure

Donations

Also we would be happy to get donations. You can buy our asset on Nxt Assets Exchange: https://trade.secureae.com/#5841059555983208287, Bitcoin wallet is 17YksFD7eRB4NhPfEtGrGnuvuwpkAeBd7f .


Repository URL is https://github.com/ConsensusResearch/Scorex-Lagonaki


P.S. Posted to my weblog as well: http://chepurnoy.org/blog/2015/05/scorex-ultracompact-cryptocurrency-engine-for-hackers/
P.P.S. Will be offline for next few days visiting Lagonaki  So replies will be posted on Monday. Sorry for that.

Event page is here http://www.meetup.com/SF-Bitcoin-Devs/events/221241204/

Nxt developer & smartcontract.com cofounder Alexander Chepurnoy will give a detailed description of an Nxt-like proof-of-stake consensus algorithm & possible known improvements of it. Different attacks on the algo (short & long private forks, history attacks, and the very famous Nothing-at-Stake attack) will be considered along with simulation results. An innovative approach for proof-of-stake consensus improvement will then be presented. Finally, after a brief overview of some formal models around blockchain properties being built, an ultra-compact cryptocurrency engine for hackers within just 4K lines of Scala code will be presented!

Paper on different attacks related to multibranching forging is published by Consensus Research https://github.com/ConsensusResearch/articles-papers/blob/master/multistrategy/multistrategy.pdf

TL/DR version and consequences:

- multibranch forging gives measurable possibility to earn more fees. I guess Nxt should not ignore it in long-term as the profitable activity will be implemented by somebody sooner or later

- there's no long-range attack against a blockchain V. Buterin described, only short-range. The short-range attack doesn't allow double-spending but gives multibranching forger possibility to earn more fees in singlebranch environment by producing few blocks in a row. However producing few blocks in a row could be an issue too (e.g. evil forger may postpones orders submissions etc) but not critical at the moment.

- not explicitly stated in the paper but easily derived, a long delay between blocks not only annoying but also a security problem as it's the moment for short-range attack could happens

- we have formally defined nothing-at-stake attack(again, using Buterin's informal definition) and made initial simulations. We haven't included their results in paper as they are seems to be too raw, but I can reveal them here: N@S attack could happens only in short-range, e.g. for within 20 blocks for 10% stake, so with 30 confirmations we haven't observed the successful attack. Also please note the attack has pretty unpredictable nature for attacker, so he can hardly enforce it, even in theory(in practice it's even harder to get it done properly). The correlation with stake size is still the open question, but it's nearly impossible to attack a proof-of-stake currency with "1% stake even" as stated by Buterin

- the N@S simulation tool is published also https://github.com/ConsensusResearch/MultiBranch  so feel free to make your own experiments



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Consensus Research is the micro-group of two researchers working on Proof-of-Stake consensus algorithm investigation at the moment. We're raising funds via NXT Assets Exchange ( https://trade.secureae.com/#5841059555983208287 ), have own GitHub https://github.com/ConsensusResearch/ and subforum on NXT forum: https://nxtforum.org/consensus-research/ , also check my personal blog please http://chepurnoy.org/