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’.
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!
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.

You cannot be a crypto investor or entrepreneur without having a real understanding of the differences between these types of blockchains as well as their implications. Even if they are based on similar principles, their operation is, in fact, different to all levels. So the tokens issued by these blockchains will not be assessed in the same manner.
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.
In this article, I will intent to do a public vs private (permissioned) blockchain comparison. This will include an examination of what exactly the roles of these two types of blockchain really are and why big businesses should quickly move to adopt them. This analysis will look at why private blockchains are better suited to big business use when compared to public ones.
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.

Byzantine fault tolerance (BFT) is what keeps the blockchain fundamentally secure. For simplicity, let’s say there were 100 nodes in a blockchain network (there are currently about 10,500 full Bitcoin nodes in the world). What happens when one node wants to tamper with the latest block and say other Bitcoin users sent him a whole bunch of Bitcoin when they really didn’t?
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.

This type of permissioned blockchain model offers the ability to leverage more than 30 years of technical literature to realize significant benefits. Digital identity in particular, is fundamental for most industry use cases, be it handling supply chain challenges, disrupting the financial industry, or facilitating security-rich patient/provider data exchanges in healthcare. Only the entities participating in a particular transaction will have knowledge and access to it — other entities will have no access to it. Permissioned blockchains also permit a couple of orders of magnitude greater scalability in terms of transactional throughput.