blockchain architecture

The distributed (blockchain) system:

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The individual block architecture:

detailedblockchain

components:

  • block reference number
  • hash of previous block: address/link/path to previous block, the (intangible) connective tissue between the blocks
  • time stamp: how we know its place in history
  • block nonce: in cryptography, this is an arbitrary number that may only be used once, it exists to prove that this block is an original block and to allow more blocks to be produced
  • transactions (txn):  a public log of past transactions (or any type of information: identity, certificates, titles) that is replicated across the system

example using Bitcoin, from Bitcoin Mining Explained Like You’re Five:
“When you first open your Bitcoin wallet, your computer automatically connects to a handful of other users (called peers) who are also operating the wallet software. Whenever you make a transaction, your computer broadcasts it to the peers you’ve connected to. Upon receiving the transaction, each peer will perform a series of about 20 checks to make sure the transaction is valid (including checking the digital signature to verify that you are in fact the owner), then relay it to its peers. Through this process the transaction will propagate throughout the network eventually reaching all users.”

blockchains: podcast

From Ethereum and Cryptocurrency with Gavin Wood

“So when we say free trust, really what we’re talking about is this notion that there are machines and organizations and individuals with an elevated trust rating in the world so when we interact with a bank or with the government we sort of innately trust them. In the case of the government, we have to trust them, we aren’t giving any choice and the same is sort of true for many of the institutions.

And these guys form nexuses, they form very particular points in the fabric of society, in that we can go to them for these services and we can’t go to anybody else, it’s not like I can do my banking with my best friend, who I actually do trust.

So when we’re talking about trying to architect systems — like financial systems, to take a poignant example– we could architect these in the way they’ve always been architected: sort of server – client, where the server is trusted and the client isn’t, and that’s what we’ve done so far, or we could architect them in what I would call a “trust free” fashion, where there isn’t really a trusted server, there isn’t really a sort of trusted organization, there’s just peers. And peers verify what each other says by virtue of knowing enough information that they actually can.”

So if you look at Bitcoin, the only reason Bitcoin really works is that all of the nodes on the network don’t have to trust the other nodes, they only need to trust themselves. If they had to trust the other nodes, it wouldn’t really be trust free.”