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judymcconville@roadrunner.com 2017-05-03 09:45:54 -07:00
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@ -146,9 +146,9 @@ If there is no traffic on a connection, nodes will periodically send a message t
((("bitcoin network", "full nodes")))((("full-node clients")))((("blockchain technology", "full blockchain nodes")))Full nodes are nodes that maintain a full blockchain with all transactions. More accurately, they probably should be called "full blockchain nodes." In the early years of bitcoin, all nodes were full nodes and currently the Bitcoin Core client is a full blockchain node. In the past two years, however, new forms of bitcoin clients have been introduced that do not maintain a full blockchain but run as lightweight clients. We'll examine these in more detail in the next section.
((("blocks", "genesis block")))((("genesis block")))Full blockchain nodes maintain a complete and up-to-date copy of the bitcoin blockchain with all the transactions, which they independently build and verify, starting with the very first block (genesis block) and building up to the latest known block in the network. A full blockchain node can independently and authoritatively verify any transaction without recourse or reliance on any other node or source of information. The full blockchain node relies on the network to receive updates about new blocks of transactions, which it then verifies and incorporates into its local copy of the blockchain.
((("blocks", "genesis block")))((("genesis block")))((("blockchain technology", "genesis block")))Full blockchain nodes maintain a complete and up-to-date copy of the bitcoin blockchain with all the transactions, which they independently build and verify, starting with the very first block (genesis block) and building up to the latest known block in the network. A full blockchain node can independently and authoritatively verify any transaction without recourse or reliance on any other node or source of information. The full blockchain node relies on the network to receive updates about new blocks of transactions, which it then verifies and incorporates into its local copy of the blockchain.
Running a full blockchain node gives you the pure bitcoin experience: independent verification of all transactions without the need to rely on, or trust, any other systems. It's easy to tell if you're running a full node because it requires 20+ gigabytes of persistent storage (disk space) to store the full blockchain. If you need a lot of disk and it takes two to three days to sync to the network, you are running a full node. That is the price of complete independence and freedom from central authority.
((("bitcoin nodes", "full nodes")))Running a full blockchain node gives you the pure bitcoin experience: independent verification of all transactions without the need to rely on, or trust, any other systems. It's easy to tell if you're running a full node because it requires 20+ gigabytes of persistent storage (disk space) to store the full blockchain. If you need a lot of disk and it takes two to three days to sync to the network, you are running a full node. That is the price of complete independence and freedom from central authority.
((("Satoshi client")))There are a few alternative implementations of full blockchain bitcoin clients, built using different programming languages and software architectures. However, the most common implementation is the reference client Bitcoin Core, also known as the Satoshi client. More than 90% of the nodes on the bitcoin network run various versions of Bitcoin Core. It is identified as "Satoshi" in the sub-version string sent in the +version+ message and shown by the command +getpeerinfo+ as we saw earlier; for example, +/Satoshi:0.8.6/+.
@ -255,9 +255,9 @@ image::images/mbc2_0812.png[]
Bloom filters are used to filter the transactions (and blocks containing them) that an SPV node receives from its peers, selecting only transactions of interest to the SPV node without revealing which addresses or keys it is interested in.
An SPV node will initialize a bloom filter as "empty" and in that state the bloom filter will not match any patterns. The SPV node will then make a list of all the addresses, keys, and hashes that it is interested in. It will do this by extracting the public-key-hash and script-hash and transaction IDs from any unspent transaction outputs (UTXO) controlled by its wallet. The SPV node then adds each of these to the bloom filter, so that the bloom filter will "match" if these patterns are present in a transaction, without revealing the patterns themselves.
((("transaction IDs (txid)")))An SPV node will initialize a bloom filter as "empty" and in that state the bloom filter will not match any patterns. The SPV node will then make a list of all the addresses, keys, and hashes that it is interested in. It will do this by extracting the public-key-hash and script-hash and transaction IDs from any unspent transaction outputs (UTXO) controlled by its wallet. The SPV node then adds each of these to the bloom filter, so that the bloom filter will "match" if these patterns are present in a transaction, without revealing the patterns themselves.
The SPV node will then send a +filterload+ message to the peer, containing the bloom filter to use on the connection. On the peer bloom filters are checked against each incoming transaction. The full node checks several parts of the transaction against the bloom filter, looking for a match including:
((("bitcoin nodes", "full nodes")))The SPV node will then send a +filterload+ message to the peer, containing the bloom filter to use on the connection. On the peer bloom filters are checked against each incoming transaction. The full node checks several parts of the transaction against the bloom filter, looking for a match including:
* The transaction ID
* The data components from the locking scripts of each of the transaction outputs (every key and hash in the script)