A public blockchain is ideal when the network must be truly decentralized, which means that no central entity controls the entry of the members on the network and the consensus mechanism is democratic. A democratic mechanism of consensus means that all members can become a minor and that these miners are in competition to add the blocks to the blockchain (at least when the mechanism of the evidence of the work is used).
Cuando esta transacción recibe las suficientes confirmaciones, se manda una notificación a la otra cadena de bloques (la que tú quieres utilizar) en el que se adjunta la prueba de que las monedas han sido enviadas por ti a esa dirección especial de la red. Tras ello, en la sidechain se creará, de forma automática, el mismo número exacto de activos que bitcoins se mandaron, dándote a ti el control de los mismos. Es decir, replica en el nuevo activo la cuantía que has enviado de la cadena principal a la sidechain. ¡Muy importante! Recordar que no se han creado o destruido nuevos bitcoins. Simplemente se han movido hasta que no estén usándose en la sidechain.
In simple terms, public blockchains can receive and send transactions from anybody in the world. They can also be audited by anybody, and every node has as much transmission power as any other. Before a transaction is considered valid, it must be authorized by each of its constituent nodes via the chain’s consensus process. As long as each node abides by the specific stipulations of the protocol, their transactions can be validated, and thus add to the chain
Developers and Cryptocurrency enthusiasts have been looking at expanding Bitcoins functionality as mainstream adoption increases. Side chains would increase the resilience of Bitcoin: If one of the sidechains was to be compromised, only the Bitcoins on that chain would be lost, while other sidechains and the Blockchain would continue like normal. This would further stabilize the Bitcoin network and increase security.
There is a whole other issue of identity theft that needs to be addressed. Just a short note here as this is a big subject: If the private key to identity object is stolen, the true owner of the identity needs to have a way to change the key. One approach to that would be to use the private key of the bitcoin transaction that created the first version of the identity object. Another way could be to prove the ownership of other public keys on the identity object, like the one used for encryption (PGP key management suggests a separate key for each purpose, signing, encryption, etc.). Other non-automatic ways could include a trusted third-party, social proof, etc.
Now, making experimental or rapid changes to Bitcoin is very risky and so change happens slowly. So if the one-size-fits-all architecture of Bitcoin doesn’t suit a particular use-case, you have a problem. You either have to use an entirely different cryptocurrency (or build one!). Or you have to use (or build) a centralized service, which brings new risks.
Cohen recently noted that before blockchain is practical in retail, brands have to understand its relevance. NPD said it’s not just about payment methods or sourcing transparency. It also has the potential to touch all areas of a company. Cohen highlights a few areas where blockchain has the ability to impact retail including revolutionizing supply chain management, preventing against counterfeiting, simplifying payments and creating safer data security.
Zestminds is an IT consulting and services provider, providing end-to-end consulting for global clients. Zestminds has partnered with several start-ups to SME in building their next generation information infrastructure for competitive advantage. The Zestminds portfolio of services includes legacy application maintenance, large application development, e-strategy consulting and solutions. The offshore Model of the company leverages talent and inf ... Read more
Blockchains that are private or permissioned work similarly to public blockchains but with access controls that restrict those that can join the network, meaning it operates like a centralised database system of today that limits access to certain users. Private Blockchains have one or multiple entities that control the network, leading to the reliance on third-parties to transact. A well-known example would be Hyperledger.
Sidechains as an idea have existed and had been floating around for quite some time now, the bases is to extend the decentralization of trust into other sectors and to other digital assets. However, while this all sounds great it's a perfect example of good in theory but not so much in practice. Nevertheless, this hasn't stopped people from trying with groups such as Blockstream exploring the idea and our friends over at Rootstock co-creating a Sidechain which is allowing Litecoin and Bitcoin to execute smart contracts and all without changing the core software of the original currency.
The first work on a cryptographically secured chain of blocks was described in 1991 by Stuart Haber and W. Scott Stornetta.[10][6] They wanted to implement a system where documents' timestamps could not be tampered with or backdated. In 1992, Bayer, Haber and Stornetta incorporated Merkle trees to the design, which improved its efficiency by allowing several documents to be collected into one block.[6][11]

“The reason why you put up private blockchains is potentially because you want to have control over the participants in the blockchain. So as we have banks and financial institutions, who have to worry heavily about regulations, they can’t use the public blockchains right now because they are open and permission-free, and anyone can participate, and that’s contradictory to the regulations to which they must abide.

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.
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.
Jump up ^ Shah, Rakesh (1 March 2018). "How Can The Banking Sector Leverage Blockchain Technology?". PostBox Communications. PostBox Communications Blog. Archived from the original on 17 March 2018. Banks preferably have a notable interest in utilizing Blockchain Technology because it is a great source to avoid fraudulent transactions. Blockchain is considered hassle free, because of the extra level of security it offers.
Public blockchains are open, and therefore are likely to be used by very many entities and gain some network effects. To give a particular example, consider the case of domain name escrow. Currently, if A wants to sell a domain to B, there is the standard counterparty risk problem that needs to be resolved: if A sends first, B may not send the money, and if B sends first then A might not send the domain. To solve this problem, we have centralized escrow intermediaries, but these charge fees of three to six percent. However, if we have a domain name system on a blockchain, and a currency on the same blockchain, then we can cut costs to near-zero with a smart contract: A can send the domain to a program which immediately sends it to the first person to send the program money, and the program is trusted because it runs on a public blockchain. Note that in order for this to work efficiently, two completely heterogeneous asset classes from completely different industries must be on the same database - not a situation which can easily happen with private ledgers. Another similar example in this category is land registries and title insurance, although it is important to note that another route to interoperability is to have a private chain that the public chain can verify, btcrelay-style, and perform transactions cross-chain.
A diferencia con la, hasta ahora, plataforma estrella de smart contracts Ethereum, otra de las diferencias más importantes de Lisk es que, en Lisk, cada aplicación corre sobre su propia sidechain y no sobre una única cadena, cómo es el caso de Ethereum. Por lo tanto, un entorno propio e independiente que podrá exprimir cada desarrollador para cada DAPP desarrollada con un backend en JS/NodeJS y un frontend HTML/CSS/JS.
thank you for the clear explanation of this. so in essence, by locking bitcoins to a particular address we’ve created an asset (collateral). then on the other sidechain (marketplace) we get issued shares against the asset, which we can sell. anyone holding a share can then redeem it against the asset. I think that’s an analogy that finance types would get

To scale Blockchain, sidechain or childchain solutions cannot be undermined. Sidechains are separate Blockchains that are linked to the main Blockchain using a two-way peg. They are an auxiliary network that executes the complementary function of: faster transactions, lower transaction costs and greater scalability in terms of the number of transactions that can be supported in a network at a given time.
Public blockchains provide a way to protect the users of an application from the developers, establishing that there are certain things that even the developers of an application have no authority to do. From a naive standpoint, it may be hard to understand why an application developer would want to voluntarily give up power and hamstring themselves. However, more advanced economic analysis provides two reasons why, in Thomas Schelling's words, weakness can be a strength. First, if you explicitly make it harder or impossible for yourself to do certain things, then others will be more likely to trust you and engage in interactions with you, as they are confident that those things are less likely to happen to them. Second, if you personally are being coerced or pressured by another entity, then saying "I have no power to do this even if I wanted to" is an important bargaining chip, as it discourages that entity from trying to compel you to do it. A major category of pressure or coercion that application developers are at risk of is that by governments, so "censorship resistance" ties strongly into this kind of argument.
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Jump up ^ Kopfstein, Janus (12 December 2013). "The Mission to Decentralize the Internet". The New Yorker. Archived from the original on 31 December 2014. Retrieved 30 December 2014. The network's 'nodes'—users running the bitcoin software on their computers—collectively check the integrity of other nodes to ensure that no one spends the same coins twice. All transactions are published on a shared public ledger, called the 'block chain.'
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)”.
Since extension blocks can be implemented via soft forks, the features of the extension blocks are essentially opt-in for users. Even in the case of extension blocks with a larger block size limit, users are not forced to upgrade and validate or propagate blocks that are much larger in size. Those who wish to enjoy the level of decentralization offered by 1MB blocks can continue to do so, while those who would like to experiment with much larger block size limits can do so on an opt-in basis.
As you know, we at LTP have been doing a lot of research to understand other use cases of blockchain apart from Bitcoin-based payments. Recently we had released a comprehensive analysis of 50+ startups and 20 use-cases of blockchain. Though there have been news of large companies accepting bitcoin (Ex.: Amazon, Microsoft, Dell) and the overall acceptance reaching a 100,000+ merchants figure, upon deeper examination we realize that large corporations do not store the Bitcoin payments. They generally partner with a Bitcoin payment processor who converts the Bitcoins to cash as and when they receive a payment and this converted amount is what the corporates take into their account. What a bummer!
@Tradle. Thanks for elaborating. I’m also thinking about these things – and hear lots of other people talk about them – but I *really* struggle with the concept. It all comes down to the table I drew in this post: https://gendal.me/2014/12/19/a-simple-model-to-make-sense-of-the-proliferation-of-distributed-ledger-smart-contract-and-cryptocurrency-projects/
Anyway, new blocks do not appear on the blockchain all of a sudden – the network must achieve consensus. In other words, each transaction must be validated by the rest of the network members, so-called “nodes.” Their contribution to the final decision on consensus is equal. Each node solves a complex cryptographic problem, and when a solution is found a new block appears on the blockchain. Such algorithm is called “proof-of-work consensus protocol.”
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.
As you know, we at LTP have been doing a lot of research to understand other use cases of blockchain apart from Bitcoin-based payments. Recently we had released a comprehensive analysis of 50+ startups and 20 use-cases of blockchain. Though there have been news of large companies accepting bitcoin (Ex.: Amazon, Microsoft, Dell) and the overall acceptance reaching a 100,000+ merchants figure, upon deeper examination we realize that large corporations do not store the Bitcoin payments. They generally partner with a Bitcoin payment processor who converts the Bitcoins to cash as and when they receive a payment and this converted amount is what the corporates take into their account. What a bummer!
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.

If you want a deeper look at Proof of Stake check out our detailed POS post. In short, while Proof of Work is an effective mechanism to secure the blockchain and provides a trustless consensus paradigm, it’s extremely energy intensive because of all the computing power required to solve hash problems. Also, while it was meant to be decentralized, it’s actually becoming more centralized as miners consolidate and massive mining setups eat up larger shares of winning blocks.

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?

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, eg. 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. Of course, one can argue that one can do this on a public blockchain by giving the government a backdoor key to a contract; the counter-argument to that is that such an approach is essentially a Rube Goldbergian alternative to the more efficient route of having a private blockchain, although there is in turn a partial counter-argument to that that I will describe later.
Sometimes separate blocks can be produced concurrently, creating a temporary fork. In addition to a secure hash-based history, any blockchain has a specified algorithm for scoring different versions of the history so that one with a higher value can be selected over others. Blocks not selected for inclusion in the chain are called orphan blocks.[22] Peers supporting the database have different versions of the history from time to time. They keep only the highest-scoring version of the database known to them. Whenever a peer receives a higher-scoring version (usually the old version with a single new block added) they extend or overwrite their own database and retransmit the improvement to their peers. There is never an absolute guarantee that any particular entry will remain in the best version of the history forever. Because blockchains are typically built to add the score of new blocks onto old blocks and because there are incentives to work only on extending with new blocks rather than overwriting old blocks, the probability of an entry becoming superseded goes down exponentially[23] as more blocks are built on top of it, eventually becoming very low.[1][24]:ch. 08[25] For example, in a blockchain using the proof-of-work system, the chain with the most cumulative proof-of-work is always considered the valid one by the network. There are a number of methods that can be used to demonstrate a sufficient level of computation. Within a blockchain the computation is carried out redundantly rather than in the traditional segregated and parallel manner.[26]

• ‘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.

There are many critics of payment channels. Finding the quickest path between unconnected nodes is no trivial exercise. This is a classic “traveling salesman” problem that has been worked on by top computer scientists for decades. Critics argue that it is highly unlikely payment channels like Bitcoin’s Lightning and Ethereum’s Raiden will work as expected in practice due to complexities like the traveling salesman problem. The key for you is just to know that these projects and potential solutions to blockchain scalability issues exist. Many of the smartest minds in the industry are working actively to bring them to life.
There are many critics of payment channels. Finding the quickest path between unconnected nodes is no trivial exercise. This is a classic “traveling salesman” problem that has been worked on by top computer scientists for decades. Critics argue that it is highly unlikely payment channels like Bitcoin’s Lightning and Ethereum’s Raiden will work as expected in practice due to complexities like the traveling salesman problem. The key for you is just to know that these projects and potential solutions to blockchain scalability issues exist. Many of the smartest minds in the industry are working actively to bring them to life.
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.”