It might seem that this technology is beneficial for any business, but it is not. Quite often projects fail to justify their will of public or private blockchain implementation. The key reason to use blockchain is the inefficiency of existing centralized solution that is slow, expensive, and lacks transparency and reliability. In other cases, blockchain isn’t required.
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.
These in-channel payments would be instant, unlike current Bitcoin payments, which require an hour to be fully verified on the blockchain. What’s more, payments would be routable across multi-hop paths, like packets across the Internet — so instead of having to create a channel to every new counterparty, you could maintain a few channels to a small number of well-connected secure intermediaries and send/receive money through them.
A consortium blockchain is often said to be semi-decentralized. It, too, is permissioned but instead of a single organization controlling it, a number of companies might each operate a node on such a network. The administrators of a consortium chain restrict users' reading rights as they see fit and only allow a limited set of trusted nodes to execute a consensus protocol.

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.


Sidechains offer a way for new, more radical settings and technologies to be implemented without affecting the main chain. This ensures that the main chain is as secure as possible whilst providing the freedom to explore options which would never be considered for use on the main chain. Sidechains should be quite powerful as they provide cases like anonymity, transparency, confirmation times and turing complete options like rootstock all whilst utilizing bitcoins rather than relying on the hashing power (security) of some far less secure alt coin. That being said… there is quite some controvery regarding blockstream’s funding of most of the core development team and their inflexiblity regarding the max blocksize. This inflexibility has directly contributed to the success of ethereum and it remains to be seen whether the dream of bitcoin maximalism will survive long enough for sidechains with all of the promised functionality to be rolled out. I am skeptical.
“Such a move could allow retailers to lower prices and incentivize consumers to shop at one retailer over a competitor,” Cohen noted. “This idea is not as ludicrous as it might seem. Amazon recently registered three cryptocurrency-related domain names, suggesting a potential move into the cryptocurrency space. If large companies like Amazon, Walmart or Starbucks issued digital coins that inspired public trust, blockchain-based cryptocurrencies might gain acceptance by the public and other retail giants.”
New distribution methods are available for the insurance industry such as peer-to-peer insurance, parametric insurance and microinsurance following the adoption of blockchain.[71][72] The sharing economy and IoT are also set to benefit from blockchains because they involve many collaborating peers.[73] Online voting is another application of the blockchain.[74][75]

A consortium blockchain is part public, part private. This split works at the level of the consensus process: on a consortium chain, a pre-selected group of nodes control the consensus process, but other nodes may be allowed to participate in creating new transactions and/or reviewing it. The specific configuration of each consortium chain (i.e., which nodes have the power to authorize transactions via the consensus process, which can review the history of the chain, which can create new transactions, and more) is the decision of each individual consortium.
Saying that, Interoperability has been the missing link in conquering the obstacles faced by both private and public blockchains by empowering them to interact and exchange values across platforms seamlessly. Developers use of the Gallactic blockchain technology, that allow for private and public blockchains within its eco-system, will drive the potential to combine both public and private blockchains with innovative new solutions, designed to accomplish cross-chain exchange and greater compatibility is the way forward for all parties and their concerns.
Bitcoin’s block interval is ten minutes so it takes about five ten minutes on average for a new transaction to find its way into a block, even if it pays a high fee. This is too slow for some people so they have experimented with alternative cryptocurrencies, based on the Bitcoin code-base, which employ quicker block intervals   [UPDATED 2014-10-27 to correct my embarrassing misunderstanding of mathematics…]

Fully private blockchains: a fully private blockchain is a blockchain where write permissions are kept centralized to one organization. Read permissions may be public or restricted to an arbitrary extent. Likely applications include database management, auditing, etc internal to a single company, and so public readability may not be necessary in many cases at all, though in other cases public auditability is desired.
A company called Blockstream has been focusing on these developments and has announced the release of Sidechain Elements, which is an open-sourced framework for sidechain development. It includes a functioning code and a testing environment for working with sidechains with several components: the core network software to build an initial testing sidechain, eight new features not currently supported by bitcoin, a basic wallet and the code for moving coins between blockchains.
Sidechains interactuando con blockchain. Blockstream explica en su paper como, a las sidechains, se les añade una nueva pieza llamada two-way peg. Two-way peg es “el conector” entre ambas cadenas y se encarga de hacer la “magia” para que los bitcoins “salten” a la otra cadena. Juntando ambas cosas obtenemos las pegged sidechain: cadenas laterales conectadas en todo momento. En la imagen puedes observar como, incluso, las sidechain pueden interactuar entre ellas. ¿Llegaremos a un escenario de blockchains interactuando con aspecto fractal?
In the context of the two-way peg, the DMMS is represented by the Simplified Payment Verification Proof (SPV Proof), which is a DMMS confirming that a specific action on a PoW blockchain occurred. The SPV Proof functions as the proof of possession in the initial parent chain for its secure transfer to a sidechain. Symmetric two-way pegs are the primary type of two-way peg so we will only be referring specifically to the symmetric (compared to asymmetric) peg in this piece.
In a cooperative consensus algorithm, there is a fixed number of voters. Voters cannot leave and join randomly. All voters know each other and every voter has only one vote. If the majority agree on the value of the data, then the system is working as designed. This can handle over 30,000 transactions per second. Scaling the number of voters can be an issue, because every vote proposed by a voter must be delivered to every other voter in the consortium.
“Private blockchains are valuable to solve efficiency, security and fraud problems within traditional financial institutions, but only incrementally. Private blockchains will not revolutionize the financial system. Public blockchains, however, hold the potential to replace most functions of traditional financial institutions with software, fundamentally reshaping the way the financial system works.” 
The original Litecoin we started out with are now Rootstock Litecoin, which I can use for creating smart contracts and as previously mentioned Sidechains can exist for all types of digital assets with propositions of not only smart contracts but the ability to provide more freedom for experimentation with Beta releases of core software and Altcoins, as well as the taking over of traditional banking instruments such as the issuing and tracking of shares, bonds and other assets.
• ‘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.
A federation is a group of servers that act as an in-between point between the main chain and a sidechain. The Federation decides when the user’s coins are locked as well as when they are released. The developers of the sidechains can choose the members of the federation. The downside to using federations is that they add another layer between the sidechains and the parent chain.
Eris Industries, aims to be the provider of shared software database using blockchain technology. Blockstack, aims to provide financial institutions back office operations, including clearing & settlement on a private blockchain. Multichain, provider an open source distributed database for financial transactions. Chain Inc., a provider of blockchain API's. Chain partnered with Nasdaq OMX Group Inc., to provide a platform that enables trading private company shares with the blockchain.
Nodes can be trusted to be very well-connected, and faults can quickly be fixed by manual intervention, allowing the use of consensus algorithms which offer finality after much shorter block times. Improvements in public blockchain technology, such as Ethereum 1.0's uncle concept and later proof of stake, can bring public blockchains much closer to the "instant confirmation" ideal (eg. offering total finality after 15 seconds, rather than 99.9999% finality after two hours as does Bitcoin), but even still private blockchains will always be faster and the latency difference will never disappear as unfortunately the speed of light does not increase by 2x every two years by Moore's law.

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.


Perhaps blocks are created faster on that sidechain. Perhaps transaction scripts are “turing complete”. Perhaps you have to pay fees to incent those securing that sidechain. Who knows. The rules can be whatever those running that sidechain want them to be. The only rule that matters is that the sidechain agrees to follow the convention that if you can prove you put some Bitcoins out of reach on the Bitcoin network, the same number will pop into existence on the sidechain.
Let’s switch gears quickly before we get back to talking about trust mechanisms. We’ll define what a “smart contract” is. The first blockchain that was popularized is obviously the Bitcoin blockchain. But the functionality of Bitcoin is very limited. All it can do is record transaction information. It’s only useful to keep track of the fact that Alice sent Bob 1 Bitcoin.
However, the Lightning Network would, again, require a change to the existing Bitcoin protocol. (Though again it would be a “soft fork,” i.e. the existing blockchain would remain fully valid.) And/or — you guessed it — a Lightning sidechain. What’s more, one of the changes it requires, the elimination of transaction malleability, is handled by the Segregated Witness work in Sidechain Elements. (correction: all of of the changes required are incorporated into Elements Alpha — it’s Lightning-ready out of the box.)
Ethereum is an open-source blockchain platform that allows anyone to build and use decentralized applications running on blockchain technology. Ethereum is a programmable blockchain - it allows users to create their own operations. These operations, coded as Smart Contracts, are deployed and executed by the Ethereum Virtual Machine (EVM) running inside every node.

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]


Bitcoin se acerca a los 10,000 millones de capitalización, con una infraestructura y usuarios que requieren que todas las ideas e innovación que se desarrolla a su alrededor cumpla con un nivel de seguridad y testeo tan elevados como el propio Bitcoin. Es por esto que, al menos hasta no ser algo totalmente definnido y fiable en la blockchain test de Bitcoin, no se podrá empezar a presionar para una posible implementación en la blockchain live.
The Bitcoin White Paper was published by Satoshi Nakamoto in 2008; the first Bitcoin block got mined in 2009. Since the Bitcoin protocol is open source, anyone could take the protocol, fork it (modify the code), and start their own version of P2P money. Many so-called altcoins emerged and tried to be a better, faster or more anonymous than Bitcoin. Soon the code was not only altered to create better cryptocurrencies, but some projects also tried to alter the idea of blockchain beyond the use case of P2P money.
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.” 
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