“The consortium or company running a private blockchain can easily, if desired, change the rules of a blockchain, revert transactions, modify balances, etc. In some cases, e.g. national land registries, this functionality is necessary; there is no way a system would be allowed to exist where Dread Pirate Roberts can have legal ownership rights over a plainly visible piece of land, and so an attempt to create a government-uncontrollable land registry would in practice quickly devolve into one that is not recognized by the government itself….

The problem with Ethereum is that transactions are executed one after another. However, Aelf differs in its parallel computing blockchain capability. It scales transaction computing power inside a single side chain. Now imagine the power when you have thousands of side chains. For any unrelated transactions, it is safe to execute them concurrently.

“The consortium or company running a private blockchain can easily, if desired, change the rules of a blockchain, revert transactions, modify balances, etc. In some cases, e.g. national land registries, this functionality is necessary; there is no way a system would be allowed to exist where Dread Pirate Roberts can have legal ownership rights over a plainly visible piece of land, and so an attempt to create a government-uncontrollable land registry would in practice quickly devolve into one that is not recognized by the government itself….


@gendal, good question. Think of the identity hash as a bitcoin address, it is indeed public. So to assert anything with this identity you need to sign the object you are creating or changing with the identity’s private key. Specifically it is a private key that corresponds to a public key that you published in your identity’s object (json). The signature is not placed on the bitcoin transaction, as OP_RETURN has only 40 bytes. The signature is added to a [json] object that is modified with this identity. If you see any fault with this, please let me know.
Congratulations! You’ve just educated yourself on the most common advanced topics in blockchain that you’ll hear about. By understanding these concepts, you have a firmer grasp on the fundamental tradeoffs and latest research on the blockchain than most industry “experts”! Better yet, next time you hear your colleagues around the water cooler talking about state channels, the Lightning Network and Byzantine fault tolerance, not only will you know what they’re talking about but you might be able to teach them a thing or two!
Side chains have two main advantages. Their first advantage they have is that they are permanent. You do not have to create a new sidechain every time you need to use one. Once a side chain is built, it is maintained and can be used by anyone doing a specified task off the main chain. The other advantage of sidechains is that they allow interaction between different cryptocurrencies. Developers get the opportunity to test software upgrades as well as beta coin releases before they are released on the main chain.
The witnesses who put more funds in escrow have a greater chance of mining (or minting) the next block. The incentives line up nicely here. There are only a few witnesses and they get paid to be witnesses, so they are incentivized to not cheat. If they do cheat and get caught, they not only get voted out in favor of the next eagerly awaiting witness, they lose all the funds they had in escrow.
The top 10 Ethereum decentralized apps (DApps) have daily active user counts in the thousands. Compare this with a centralized platform like Facebook, which has over a billion daily users, and you can see just how small scale blockchain use still remains. For a detailed comparison, read “State of the DApps: 5 Observations From Usage Data (April 2018)”.
Sidechain is a blockchain that runs parallel to the main blockchain. It extends the functionality of interplorable blockchain networks. Interpolable blockchain networks signifies the ability to share data between different computer systems on different machines. It means that data can be sent and received between interconnected networks eliminating the possibility of negative impact to the networks. Sidechain enables this to be done in a decentralised manner to transfer and synchronise tokens between two chains.
A blockchain is so-called “public” (or open) when anyone can become a member of the network without conditions of admission. In other words, anyone wishing to use the service proposed by the network can download the protocol locally without having to reveal his or her identity or meet predetermined criteria. A protocol is a computer program that could be compared to a Charter in that it defines the rules of operation of a network based on a blockchain. For example, the members of the bitcoin network download the Bitcoin protocol (through the intermediary of their “wallet”) to be able to join the network and exchange bitcoins, but the only condition is to have an Internet connection.

Plasma, a project by Ethereum, uses this side chain concept. It encourages transactions to happen on side chains (or child chains). An authority governs each of the child chains. If the authority starts acting maliciously, anyone on the child chain can quit the child chain and take back their pegged assets on the main chain. It’s in its early stages of development but shows a lot of promise in handling some of Ethereum’s scalability issues.
In September 2015, the first peer-reviewed academic journal dedicated to cryptocurrency and blockchain technology research, Ledger, was announced. The inaugural issue was published in December 2016.[91] The journal covers aspects of mathematics, computer science, engineering, law, economics and philosophy that relate to cryptocurrencies such as bitcoin.[92][93]
A sidechain is a separate blockchain that is attached to its parent blockchain using a two-way peg. The two-way peg enables interchangeability of assets at a predetermined rate between the parent blockchain and the sidechain. The original blockchain is usually referred to as the ‘main chain’ and all additional blockchains are referred to as ‘sidechains’. The blockchain platform Ardor refers to its sidechains as ‘childchains’.

This is justified by observing that, in our pre-sidechain world, miners always want things to be correct. In theory, the incentives of miners and investors are very strongly aligned: both are compensated most when the exchange rate is highest. And, in practice, we do not see large reorganizations (where miners can “steal”, by first depositing BTC to major exchanges, then selling that BTC for fiat (which they withdraw), and finally rewriting the last 3 or 4 days of chain history, to un-confirm the original deposits). These reorgs would devastate the exchange rate, as they would cast doubt on the entire Bitcoin experiment. The thesis of Drivechain is that sidechain-theft would also devastate the exchange rate, as it would cast doubt on the entire sidechain experiment (which would itself cast doubt on the Bitcoin experiment, given the anti-competitive power of sidechains).


If one group of nodes continues to use the old software while the other nodes use the new software, a split can occur. For example, Ethereum has hard-forked to "make whole" the investors in The DAO, which had been hacked by exploiting a vulnerability in its code.[31] In this case, the fork resulted in a split creating Ethereum and Ethereum Classic chains. In 2014 the Nxt community was asked to consider a hard fork that would have led to a rollback of the blockchain records to mitigate the effects of a theft of 50 million NXT from a major cryptocurrency exchange. The hard fork proposal was rejected, and some of the funds were recovered after negotiations and ransom payment.[32]
This list is not exhaustive. There are plenty of public blockchains, and they are actively adopted by such industries as FinTech, gaming, logistics, and beyond. However, it not always makes sense to move certain processes and businesses to the public network as the latter are characterized by comparatively low speed of transactions execution and high costs. Indeed, every transaction requires a consensus of the entire network. Unfortunately, it takes time and resources.
Terasol's mission is to create apps that would help people learn and grow with tech. Every member of Terasol shares the same dream of working towards building apps that would not only create history but also give people the opportunity of experiencing tech they did not know could become essential part of their lives. A lot has changed since we developed our first app; we have grown with each project and refined our skills to serve nothin ... Read more

This is justified by observing that, in our pre-sidechain world, miners always want things to be correct. In theory, the incentives of miners and investors are very strongly aligned: both are compensated most when the exchange rate is highest. And, in practice, we do not see large reorganizations (where miners can “steal”, by first depositing BTC to major exchanges, then selling that BTC for fiat (which they withdraw), and finally rewriting the last 3 or 4 days of chain history, to un-confirm the original deposits). These reorgs would devastate the exchange rate, as they would cast doubt on the entire Bitcoin experiment. The thesis of Drivechain is that sidechain-theft would also devastate the exchange rate, as it would cast doubt on the entire sidechain experiment (which would itself cast doubt on the Bitcoin experiment, given the anti-competitive power of sidechains).
Imagine there is a Bitcoin-like system out there that you’d like to use. Perhaps it’s litecoin or ethereum or perhaps it’s something brand new.   Maybe it has a faster block confirmation interval and a richer scripting language. It doesn’t matter.   The point is: you’d like to use it but would rather not have to go through the risk and effort of buying the native tokens for that platform. You have Bitcoins already. Why can’t you use them?
The consensus mechanism involves ascertaining transaction validity and uniqueness. Smart contracts address the validity portion. To ensure uniqueness, the protocol program in Corda checks whether any other transaction has used any of the input states of this transaction. If no other transaction has used any of the input states, that this transaction is unique.
Walmart recently filed patents that could allow the retailer to store vendor and consumer e-commerce payment data using blockchain technology to improve security. This application would encrypt payment information in digital shopping systems and create a network able to automatically conduct transactions on behalf of a customer. The payments would be received by one vendor or more, depending on the services and who provided them.
NPD said the next step for retailers is to develop their own cryptocurrency to prevent customers from having to use credit cards when shopping online. NPD said the practice makes sense for the retailer, because if the customer could send the payment transfer via blockchain, it would avoid third-party clearing house fees retailers pay for processing card payments.

Blockstream has also released an “Alpha” sidechain with all of those features up and running except the last, coupled to the Bitcoin testnet. (Used for testing Bitcoin software without putting real value at risk.) In the absence of the Bitcoin protocol change that will cryptographically secure the programmatic transfer of value between Bitcoin and sidechains, they’re cooperating with several external organizations to perform and validate those transfers. If and when that protocol change happens, though, pegged sidechains will be as permissionless, and as decentralized, as Bitcoin itself.


Incorporated in 2009 and headquartered in the USA, Techtic Solutions Inc. is an leading web and mobile app development company known for delivering innovative solutions for any complex problem. Our mission remains the same; “PRODUCE UNPARALLELED TECH ENABLED SOLUTIONS BENCHMARKING LATEST TECHNOLOGY STANDARDS” Facts & Figures: A service provider in over 30 countries with offices in: USA & India 250+ mobile applicatio ... Read more
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A blockchain is so-called “public” (or open) when anyone can become a member of the network without conditions of admission. In other words, anyone wishing to use the service proposed by the network can download the protocol locally without having to reveal his or her identity or meet predetermined criteria. A protocol is a computer program that could be compared to a Charter in that it defines the rules of operation of a network based on a blockchain. For example, the members of the bitcoin network download the Bitcoin protocol (through the intermediary of their “wallet”) to be able to join the network and exchange bitcoins, but the only condition is to have an Internet connection.
• ‘Difficulty’: In the Bitcoin network, miners solve an asymmetric cryptographic puzzle to mine new blocks. Over time the puzzle becomes easier, resulting in it eventually taking less than 10 minutes for each new block generation. Hence, the community updates the puzzle every 14 days and makes it more difficult, thus requiring even more computing power to handle the POW algorithm. The ‘difficulty’ parameter controls the complexity of the cryptographic puzzle. This parameter is also used in the Ethereum blockchain as well. Developers should assign a low value (between 0-10,000) to this parameter for this project thus enabling quicker mining.
When you send Bitcoins somewhere, you lay down the challenge for the next owner. Usually, you’ll simply specify that they need to know the public and private keypair that correspond to the Bitcoin address the coins were sent to. But it can be more complicated than that. In the general case, you don’t even know who the next owner is… it’s just whoever can satisfy the condition.

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In order to spend them, you have to prove you’re entitled to do so. And you do that by providing the solution to a challenge that was laid down when they were sent to you in the first place. This challenge is usually just: “prove to the world that you know the public key that corresponds to a particular Bitcoin address and are in possession of the corresponding private key”. But it can be more sophisticated than that.
A private blockchain network requires an invitation and must be validated by either the network starter or by a set of rules put in place by the network starter. Businesses who set up a private blockchain, will generally set up a permissioned network. This places restrictions on who is allowed to participate in the network, and only in certain transactions. Participants need to obtain an invitation or permission to join. The access control mechanism could vary: existing participants could decide future entrants; a regulatory authority could issue licenses for participation; or a consortium could make the decisions instead. Once an entity has joined the network, it will play a role in maintaining the blockchain in a decentralized manner.