What is the blockchain? I keep hearing about other "blockchain technologies", does this mean other cryptocurrencies or what?
The bitcoin block chain is the record of every bitcoin ever generated and every transfer of bitcoins from one party to another. Each crypto-currency that is based on the same type of technology as bitcoins has its own block chain. When people talk about other blockchains, they mean other currencies based on the same distributed currency / published transaction model (namecoin, Ixcoin, and so on).
The phrase "blockchain technology" is a reference to this model of published transactions to implement currencies with no central authority.
The bitcoin "blockchain" is in effect the general ledger of bitcoin. It is a recording of all transactions grouped into blocks. Each block represents approximately the 10 minutes of transactions, and chaining them together has the effect of adding layer up layer of transaction history.
Chaining blocks of transactions together by requiring a new block to reference the most recent prior block makes it harder to alter blocks in the past, since all subsequent blocks up to the current one would also have to be altered. In the bitcoin blockchain this is combined with a 'proof of work' that each block must include (a very large amount of work at this point), to create an unalterable history of transactions that is definitive.
New transactions can be evaluated against this general ledger with complete confidence that it is current, complete, and unalterable. With the entire blockchain publicly available anyone can do this evaluation and prove that a transaction is valid or not.
It is likely that someone referring to a "blockchain technology" is talking about any system that has this type of public general ledger.
I Hope this guide helps
Blockchain technology is like the internet in that it has a built-in robustness. By storing blocks of information that are identical across its network, the blockchain cannot:
Be controlled by any single entity. Has no single point of failure. Bitcoin was invented in 2008. Since that time, the Bitcoin blockchain has operated without significant disruption. (To date, any of problems associated with Bitcoin have been due to hacking or mismanagement. In other words, these problems come from bad intention and human error, not flaws in the underlying concepts.)
The internet itself has proven to be durable for almost 30 years. It’s a track record that bodes well for blockchain technology as it continues to be developed.
Ian Khan, TEDx Speaker“As revolutionary as it sounds, Blockchain truly is a mechanism to bring everyone to the highest degree of accountability. No more missed transactions, human or machine errors, or even an exchange that was not done with the consent of the parties involved. Above anything else, the most critical area where Blockchain helps is to guarantee the validity of a transaction by recording it not only on a main register but a connected distributed system of registers, all of which are connected through a secure validation mechanism.”
– Ian Khan, TEDx Speaker | Author | Technology Futurist
Transparent and incorruptible
The blockchain network lives in a state of consensus, one that automatically checks in with itself every ten minutes. A kind of self-auditing ecosystem of digital value, the network reconciles every transaction that happens in ten minute intervals. Each group of these transactions is referred to as a “block”. Two important properties result from this:
data is embedded within network as a whole, by definition it is public. It cannot be corrupted - altering any unit of information on the blockchain would mean using a huge amount of computing power to override the entire network. In theory, this could be possible. In practice, it’s unlikely to happen. Taking control of the system to capture Bitcoins, for instance, would also have the effect of destroying their value.
I would suggest you to stop getting boggled by technical terms like ‘decentralized distributed ledger’.Blockchain is nothing but a long chain of blocks with transactions details recorded and new blocks added after each transaction is validated and approved.
Blockchain allows transactions to take place in a secured, transparent and decentralized manner.
When a sender transfers the information, he/she uses their private key and at the same time announces the transaction information over the network. This is when a new block is created that contains information like a digital signature, timestamp along with the receiver’s public key.
This helps all transactions over blockchain technology highly secured.