shortspecialbus wrote:DC3 wrote:The purpose of the miner is to validate the blockchain. You can not have one without the other.
Of course you can, just not the specific 'bitcoin' blockchain for example. Plenty of other things that have nothing to do with cryptocurrency can use blockchains. It's a neat technology. It's just fairly associated with cryptocurrencies right now.
Right. Blockchain is an underlying technology, cryptocurrency is an application that uses it.
The Malwarebytes description is good.
Here's another, on Wikipedia.
A blockchain can contain any kind of data. In the simplest terms, a blockchain is just a ledger that's distributed across multiple computers. Each entry is a block. Each block is linked to the one ahead and behind it - the links are the chain. Each link is encrypted using a hash - a standard form of cryptography that associates data of variable length (like a list of names) to data of fixed length (like a list of two-digit numbers). This is useful because the hash doesn't tell you anything about the underlying data. In blockchain, the hash is constructed using data from the previous one. In practice, that means that every hash is related to all the others - if you want to try to alter a link, you have to alter all of them. That makes for very strong encryption.
Creating the new hashes is computationally intensive. In cryptocurrency, that's what miners do - they create the new links and they're rewarded with some of the currency. The sheer volume of doing this in currency ledgers means you need massive amounts of computing power, which means lots of hardware and a huge amount of energy expenditure.
But a blockchain doesn't care what kind of data it contains. It's good for other kinds of financial transaction (the first big company I came across that was interested in it was a big credit-card issuer - this was four years ago). My clients are talking about using it for medical records, which have to be kept very secure (medical records are really prized by identity thieves because the information is detailed and verified) but also need to be used in multiple places in the healthcare system. Databases are less secure and they're much harder to interoperate, so blockchain looks like a promising solution.
Kodak just proposed using blockchain for digital rights management, which makes lots of sense. They announced at the same time that they'd do it using their own cryptocurrency, called Kodakcoin, which makes no sense at all (why not just pay with dollars, or with an existing cryptocurrency?) That sounds like somebody went to the meeting after reading about Bitcoin in, say, Newsweek, and didn't know what he or she was talking about, and neither did anyone else in the meeting, and so Kodakcoin was born. Another sign of a market top.
But blockchain will stick around.
I guess I will have to wait until the fad plays out (when they all go bust) as many get rich quick schemes windup). That last statement ought to cause some tight jaws. 
