“RSK directly “plugs in” to achieve a perfect merged-mining and to ensure that cryptographic work, that will be discarded in Bitcoin mining, is reused in the first smart contract open-source platform secured by the Bitcoin network. RSK has an agreement with Bitcoin miners: we share with them 80% of the fees arising from transactions made within the smart contract network.”
“RSK directly “plugs in” to achieve a perfect merged-mining and to ensure that cryptographic work, that will be discarded in Bitcoin mining, is reused in the first smart contract open-source platform secured by the Bitcoin network. RSK has an agreement with Bitcoin miners: we share with them 80% of the fees arising from transactions made within the smart contract network.”
A typical use case for a private blockchain is intra-business: when a company decides to implement blockchain as a business solution, they may opt for a chain to which only company members have access. This is useful if there’s no need for anybody outside of the company to become part of the chain, because private blockchains are more efficient than public and consortium chains. Also, because they are smaller and contained, it is easier for a consensus process or other technical stipulation to be altered on a blockchain. So, for example, if the developers or proprietors want to change the cryptographic method which runs its consensus process, it is much easier to do this on a private blockchain than a public or consortium chain.

The Blockstream Satellite network broadcasts the Bitcoin blockchain to the entire planet. The satellite network provides an opportunity for nearly 4 billion people without Internet access to utilize bitcoin while simultaneously ensuring bitcoin use is not interrupted due to network interruption. Utilizing the latest open source Software Defined Radio (SDR) technologies, the Blockstream Satellite network offers a breakthrough in the cost effectiveness of satellite communications.

Private blockchains, or as I like to call them, shared databases, have a place in improving efficiency for financial institution for back-office settlement processes. They should not be seen as controversial, or part of some dialectic struggle between punks and police. To the extent that the identifying shroud of AML/KYC can be placed into public blockchain metadata (possible in Omni Layer transactions over the Bitcoin blockchain) there may even be interoperability between these two sides of the train tracks. Right now, due to state-granted monopolies to issue credit, most of the world's liquidity is still in banks. However, we believe that in the long-term, public blockchains, especially those based on work, will come to take a more significant part in the ‘System D’ informal economy, which is where most of the global economic growth will originate.” 
2) Yes – I had to keep things short/simple in this intro article in order to get across the key ideas. But you’re right: the sidechains need to be secured. But how that happens is a matter for the sidechain. If somebody can produce a false “proof” that the locked Bitcoins should be released on the Bitcoin side then that’s a problem for the sidechain, of course (somebody presumably just had their coins stolen!) but it’s irrelevant (at a macro level) on the Bitcoin side.
"I see quite a few use cases for private blockchains, and they definitely have their place. Traditional institutions won't switch to a completely public blockchain from one day to the other. A private blockchain is a great first step towards a more cryptographic future. The biggest advantages of private blockchains in comparison to centralized databases are the cryptographic auditing and known identities. Nobody can tamper with the data, and mistakes can be traced back. In comparison to a public blockchain it is much faster, cheaper and respects the company's privacy. As a conclusion, it's better to rely on a private blockchain than no cryptographic system at all. It has merits and pushes the blockchain terminology into the corporate world, making truly public blockchains a bit more likely for the future." 
Sidechains allow cryptocurrencies to interact with one another. They add flexibility and allow developers to experiment with Beta releases of Altcoins or software updates before pushing them on to the main chain. Traditional banking functions like issuing and tracking ownership of shares can be tested on sidechains before moving them onto main chains. If the security mechanisms for sidechains can be bolstered, sidechain technology holds promise for massive blockchain scalability.

Por ello, con este escenario sobre la mesa y con el objetivo de aunar esfuerzos, algunos se han preguntado: ¿Sería posible crear blockchains que sean utilizadas para casos de usos concretos, pero conectadas en todo momento a la de Bitcoin? ¿Podemos crear piezas de software que desde una blockchain se pueda saltar a otra de manera transparente, segura y descentralizada? Esto generaría, para que te hagas una imagen mental, algo así como las ruedas dentadas interconectadas de un motor, cada rueda una blockchain, todas trabajando juntas.
Jump up ^ Redrup, Yolanda (29 June 2016). "ANZ backs private blockchain, but won't go public". Australia Financial Review. Archived from the original on 3 July 2016. Retrieved 7 July 2016. Blockchain networks can be either public or private. Public blockchains have many users and there are no controls over who can read, upload or delete the data and there are an unknown number of pseudonymous participants. In comparison, private blockchains also have multiple data sets, but there are controls in place over who can edit data and there are a known number of participants.
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.
People believe that permissioned means that only a select group of people can access the data and that’s the security feature. But it’s not. Since there is no real user data on the blockchain, (you) as a member of the public, can’t verify the actual content of it. This means that data resides in a location where corruption can stay undetected and data can be easily modified. So why does it even exist? Mainly because of the phenomena known as “hype surfing”; essentially reusing old technology and strapping a blockchain sticker on it gets IBM salesmen a foot in the door to institutions who can’t evaluate the technology accurately in the first place. Unfortunately, even some teams doing public token offerings started to sell this deeply flawed approach to the public.

Using Rootstock as an example, in order to transfer assets from one chain to the other a user on the parent first has to send their coins to a special output address where they will consequently become locked and un-spendable. Once the transaction is completed, SPV then confirms it across the chains and after waiting out a contest period, which is just a secondary method to help prevent double spending, the equivalent amount will be credited and spendable on the Sidechain and vice versa.
A blockchain is a decentralized, distributed and public digital ledger that is used to record transactions across many computers so that the record cannot be altered retroactively without the alteration of all subsequent blocks and the consensus of the network.[1][18] This allows the participants to verify and audit transactions inexpensively.[19] A blockchain database is managed autonomously using a peer-to-peer network and a distributed timestamping server. They are authenticated by mass collaboration powered by collective self-interests.[20] The result is a robust workflow where participants' uncertainty regarding data security is marginal. The use of a blockchain removes the characteristic of infinite reproducibility from a digital asset. It confirms that each unit of value was transferred only once, solving the long-standing problem of double spending. Blockchains have been described as a value-exchange protocol.[13] This blockchain-based exchange of value can be completed quicker, safer and cheaper than with traditional systems.[21] A blockchain can assign title rights because, when properly set up to detail the exchange agreement, it provides a record that compels offer and acceptance.
By contrast, the Bitcoin blockchain is not Turing complete since it has little to no ability for data manipulation. It has no ability for a user to deploy if else or goto statements. This is a bit of a simplification but anytime you hear someone say something is “Turing complete” you can do a quick check to see if there is functionality for data changes, memory changes and if/else statements. If there is, that’s usually what they mean.
Peer-to-peer blockchain networks lack centralized points of vulnerability that computer crackers can exploit; likewise, it has no central point of failure. Blockchain security methods include the use of public-key cryptography.[4]:5 A public key (a long, random-looking string of numbers) is an address on the blockchain. Value tokens sent across the network are recorded as belonging to that address. A private key is like a password that gives its owner access to their digital assets or the means to otherwise interact with the various capabilities that blockchains now support. Data stored on the blockchain is generally considered incorruptible.[1]
By the end of this post, you’ll be able to freely participate in conversations like the above. This is not a coding tutorial, as we’ll just be presenting important concepts at a high level. However, we may follow up with programming tutorials on these ideas. This article will be helpful to both programmers and non-programmers alike. Let’s get going!
The main point of a side-chain is to allow cryptocurrency networks to scale and interact with one-another. For example alt-coins and Bitcoin run on separate chains, however side chains allow for these separate currencies to be transferred through these two-way 'portal's or interfaces via a fixed conversion amount. Added benefits of side-chains are different asset classes like,stocks, bonds etc being integrated through a converted price onto the main chain, along with additional functionality like smart contracts,unique D-Apps, micro-payments and security updates that can be later incorporated into the primary network from these side-chains.
Federated Blockchains operate under the leadership of a group. As opposed to public Blockchains, they don’t allow any person with access to the Internet to participate in the process of verifying transactions. Federated Blockchains are faster (higher scalability) and provide more transaction privacy. Consortium blockchains are mostly used in the banking sector. The consensus process is controlled by a pre-selected set of nodes; for example, one might imagine a consortium of 15 financial institutions, each of which operates a node and of which 10 must sign every block in order for the block to be valid. The right to read the blockchain may be public, or restricted to the participants.
When blockchain technology was introduced to the public in 2008 (via Satoshi Nakamoto’s famous white paper), it would have been hard to predict that private or consortium blockchains would become popular. But recently, there’s been a lot of buzz about this in the digital currency community. Many companies are beginning to experiment with blockchain by implementing private and consortium chains, although some people are critical of this. This discussion not only centers on use cases and benefits, but whether non-public blockchains are an appropriate application of the protocol to begin with.
“Not only is decentralization, open protocols, open source, collaborative development and living in the wild a feature of Bitcoin, that’s the whole point. And if you take a permissioned ledger and say, that’s all nice, we like the database part of it, can we have it without the open decentralized P2P [peer-to-peer] open source non-controlled distributed nature of it, well you just threw out the baby with the bathwater.” 
Consortium blockchains: a consortium blockchain is a blockchain where the consensus process is controlled by a pre-selected set of nodes; for example, one might imagine a consortium of 15 financial institutions, each of which operates a node and of which 10 must sign every block in order for the block to be valid. The right to read the blockchain may be public, or restricted to the participants, and there are also hybrid routes such as the root hashes of the blocks being public together with an API that allows members of the public to make a limited number of queries and get back cryptographic proofs of some parts of the blockchain state. These blockchains may be considered "partially decentralized".
Of course, the drawbacks of public and private blockchains are still very much present in the case consortium chains. This all depends on the way each consortium is constructed: a more public consortium chain will bear the burdens of public chains, while a more private one might suffer from the relative lack of openness and disintermediation. The right configuration depends on the needs and vision for each specific chain. Strategy and tailoring are always necessary to get the best solution.
Put simply, sidechaining is any mechanism that allows tokens from one blockchain to be securely used within a completely separate blockchain but still moved back to the original chain if necessary. By convention the original chain is normally referred to as the "main chain", while any additional blockchains which allow users to transact within them in the tokens of the main chain are referred to as "sidechains". For example, a private Ethereum-based network that had a linkage allowing ether to be securely moved from the public Ethereum main chain onto it and back would be considered to be a sidechain of the public network.

Another promise of sidechains is the ability to have a stronger and faster mainchain, as transactions can happen on one of the sidechains. If users or developers are dissatisfied with the costs of sending a transaction and the transaction speed of the mainchain, they can use and or deploy their dapp on one of the sidechains. This leads to a more diversified network and a stronger, faster and more robust mainchain.
The sidechains vision of the future is of a vast globe-spanning decentralized network of many blockchains, an intertwined cable rather than a single strand, each with its own protocol, rules, and features — but all of them backed by Bitcoin, and protected by the Bitcoin mining network, as the US dollar was once backed by gold. Sidechains can also be used to prototype changes to the fundamental Bitcoin blockchain. One catch, though: this will require a small tweak to the existing Bitcoin protocol.

Space-O is one stop solution for all your mobile software development needs. From concept to development to marketing to ongoing maintenance, Space-O delivers. We are now one of the top mobile app development companies in India by following the success mantra of “Design-led-Engineering”. We work with best-of-the-best fine art grads from top design institutes such as NID and best-of-the-best engineers. Space-O's ability ... Read more
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 consensus mechanism is centralized in the hands of a single entity which mission is to verify and add all transactions to the blockchain. A network based on a private blockchain, therefore does not need to use a mechanism such as “Proof of Work” or “Proof of Stake” which are complicated to implement and expensive. The problems of security being much more simple in the case of private blockchains, it is possible to apply the mechanisms of consensus lighter, more effective and therefore easy to deploy such that the BFT.
Let's explore if there is a hybrid blockchain concept (third type). A consortium blockchain would be a mix of both the public and private. Wherein the ability to read & write could be extended to a certain number of people/nodes. This could be used by groups of organization/firms, who get together, work on developing different models by collaborating with each other. Hence, they could gain a blockchain with restricted access, work on their solutions and maintain the intellectual property rights within the consortium.

The first question to answer is “What is public blockchain?” The very name of this type of networks implies that they are open and permissionless. It means that anyone in the world can join the network, add blocks and view the information stored there. Indeed, public blockchains are totally transparent as any of their members can audit them. For this reason, independent participants can easily agree on transactions without middlemen and the fear of deception.

A public blockchain has absolutely no access restrictions. Anyone with an internet connection can send transactions[disambiguation needed] to it as well as become a validator (i.e., participate in the execution of a consensus protocol).[84][self-published source?] Usually, such networks offer economic incentives for those who secure them and utilize some type of a Proof of Stake or Proof of Work algorithm.


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.
Nikolai Hampton pointed out in Computerworld that "There is also no need for a '51 percent' attack on a private blockchain, as the private blockchain (most likely) already controls 100 percent of all block creation resources. If you could attack or damage the blockchain creation tools on a private corporate server, you could effectively control 100 percent of their network and alter transactions however you wished."[9] This has a set of particularly profound adverse implications during a financial crisis or debt crisis like the financial crisis of 2007–08, where politically powerful actors may make decisions that favor some groups at the expense of others,[51][52] and "the bitcoin blockchain is protected by the massive group mining effort. It's unlikely that any private blockchain will try to protect records using gigawatts of computing power—it's time consuming and expensive."[9] He also said, "Within a private blockchain there is also no 'race'; there's no incentive to use more power or discover blocks faster than competitors. This means that many in-house blockchain solutions will be nothing more than cumbersome databases."[9]
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.
Setting up an environment to test and research blockchain requires an ecosystem with multiple systems to be able to develop research and test. The big players in the cloud industry like Amazon(AWS), Microsoft(Azure), IBM(BlueMix) have seen the potential benefits of offering blockchain services in the cloud and started providing some level of BaaS to their customers. Users will benefit from not having to face the problem of configuring and setting up a working blockchain. Hardware investments won’t be needed as well. Microsoft has partnered with ConsenSys to offer Ethereum Blockchain as a Service (EBaaS) on Microsoft Azure. IBM(BueMix) has partnered with Hyperledger to offer BaaS to its customers. Amazon announced they would be offering the service in collaboration with the Digital Currency Group. Developers will have a single-click cloud-based blockchain developer environment, that will allow for rapid development of smart contracts.
Plasma is a proposed framework for incentivized and enforced execution of smart contracts which is scalable to a significant amount of state updates per second (potentially billions) enabling the blockchain to be able to represent a significant amount of decentralized financial applications worldwide. These smart contracts are incentivized to continue operation autonomously via network transaction fees, which is ultimately reliant upon the underlying blockchain (e.g. Ethereum) to enforce transactional state transitions.
By definition, blockchain is a ledger of all transactions that have been executed and could be seen as a write-only platform, wherein transactions once executed cannot be modified later. This platform has been further divided into Public and Private blockchain. Is there a third one? a hybrid mode such as a ‘Consortium blockchain’ as represented by Vitalik Buterin, founder of Ethereum, a decentralized web 3.0 publishing platform.
Loom Network is a Platform as a Service built on top of Ethereum that allows developers to run large-scale decentralized applications. This lets developers build DApps with the trust and security of the world’s most secure public blockchain, along with the computing resources necessary to run commercial-scale services. Like how Filecoin tokenized disk space, Loom aims to be the tokenized application protocol of the new decentralized web.
In October 2014, the MIT Bitcoin Club, with funding from MIT alumni, provided undergraduate students at the Massachusetts Institute of Technology access to $100 of bitcoin. The adoption rates, as studied by Catalini and Tucker (2016), revealed that when people who typically adopt technologies early are given delayed access, they tend to reject the technology.[85]
The first question to answer is “What is public blockchain?” The very name of this type of networks implies that they are open and permissionless. It means that anyone in the world can join the network, add blocks and view the information stored there. Indeed, public blockchains are totally transparent as any of their members can audit them. For this reason, independent participants can easily agree on transactions without middlemen and the fear of deception.
2) Yea, blockchain could be a suboptimal MQ Series, a slower append only persistent wire that has a lot of ready-made tools for audit and security analysis (ecosystem argument). As blockchain ecosystem grows all kinds of data transformation tools will appear (e.g. we are working on such). Inside blockchain could be tuned to be less PoW intensive and to cut blocks faster. Besides, the variations of PoS or a hybrid PoW + PoS scheme are emerging which could use the fact that inside, as you say, all network participants can have clear identities, unlike on the public bitcoin’s blockchain.
Bitcoin and Ethereum blockchains use the ‘proof of work’ (POW) consensus algorithm to provide maximum security. It relies on a process called ‘mining’, which involves nodes trying to find the cryptographic hash of the last recorded block in order to create a new block. This is a massive number-crunching operation. It’s computing-power and energy-intensive, and becomes increasingly costly as the blockchain length grows. Read more about POW in this article “Proof of work vs proof of stake comparison”. This makes such blockchains impractical in a large business context.
The public blockchain is open to anyone who wants to deploy smart contracts and have their executions performed by public mining nodes. Bitcoin is one of the largest public blockchain networks today. As such, there is limited privacy in the public blockchain. Mining nodes in the public blockchain requires a substantial amount of computational power to maintain the distributed ledger at a large scale. In the Ethereum public blockchain, smart contract codes can be viewed openly.

– A cost per transactions which can be high: Miners only participate in the process of mining because they hope to get the reward (coinbase and fees) allocated to minors who have added a block to the blockchain. For them it is a business, this reward will finance the costs they have incurred in the process of mining (electricity, computer equipment, internet connection). Tokens that are distributed to them are directly issued by the Protocol, but the fees are supported by the users. In the case of the bitcoin, for example, minors receive 12.5 bitcoins for each block added, to which are added fees paid by the users to add their transactions to the blocks. These fees are variable and the higher the demand to add transactions, the higher the fees.
Security issues. Like the blockchain, the sidechain needs the work of miners to stay safe from attacks. Without sufficient power, the sidechain is vulnerable for assault. If hacked, only the sidechain will be damaged, while the main chain remains untouched and ready to continue work. If the main chain comes under the attack, the sidechain still operates, but without the value of the peg.
"I see quite a few use cases for private blockchains, and they definitely have their place. Traditional institutions won't switch to a completely public blockchain from one day to the other. A private blockchain is a great first step towards a more cryptographic future. The biggest advantages of private blockchains in comparison to centralized databases are the cryptographic auditing and known identities. Nobody can tamper with the data, and mistakes can be traced back. In comparison to a public blockchain it is much faster, cheaper and respects the company's privacy. As a conclusion, it's better to rely on a private blockchain than no cryptographic system at all. It has merits and pushes the blockchain terminology into the corporate world, making truly public blockchains a bit more likely for the future." 
×