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Merge branch 'develop' into patch-54

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Will Binns 2021-03-05 22:05:17 +01:00 committed by GitHub
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6
appdx-bitcore.asciidoc
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@ -55,11 +55,11 @@ Creating and signing a transaction from an UTXO:
----
> utxo = {
txId: transaction id containing an unspent output,
outputIndex: output index e.g. 0,
txId: txId, // transaction id containing an unspent output
outputIndex: outputIndex, // output index (e.g. 0)
address: addressOfUtxo,
script: bitcore.Script.buildPublicKeyHashOut(addressOfUtxo).toString(),
satoshis: amount sent to the address
satoshis: satoshis // amount sent to the address
}
> fee = 3000 //set appropriately for conditions on the network
> tx = new bitcore.Transaction()

12
ch07.asciidoc
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@ -782,12 +782,6 @@ Now, let's look at how this entire example would be upgraded to segwit. If Moham
Again, as with the example of P2WPKH, you can see that the Segregated Witness equivalent script is a lot simpler and omits the various script operands that you see in P2SH scripts. Instead, the Segregated Witness program consists of two values pushed to the stack: a witness version (0) and the 32-byte SHA256 hash of the redeem script.
[TIP]
====
While P2SH uses the 20-byte +RIPEMD160(SHA256(script))+ hash, the P2WSH witness program uses a 32-byte +SHA256(script)+ hash. This difference in the selection of the hashing algorithm is deliberate and is used to differentiate between the two types of witness programs (P2WPKH and P2WSH) by the length of the hash and to provide stronger security to P2WSH (128 bits of security in P2WSH versus 80 bits of security in P2SH).
====
Mohammed's company can spend the P2WSH output by presenting the correct redeem script and sufficient signatures to satisfy it. Both the redeem script and the signatures would be segregated _outside_ the spending transaction data as part of the witness data. Within the transaction input, Mohammed's ((("", startref="mohamappd")))wallet would put an empty +scriptSig+:
.Decoded transaction showing a P2WSH output being spent with separate witness data
@ -803,6 +797,12 @@ Mohammed's company can spend the P2WSH output by presenting the correct redeem s
[...]
----
[TIP]
====
While P2SH uses the 20-byte +RIPEMD160(SHA256(script))+ hash, the P2WSH witness program uses a 32-byte +SHA256(script)+ hash. This difference in the selection of the hashing algorithm is deliberate and provides stronger security to P2WSH (128 bits of security in P2WSH versus 80 bits of security in P2SH). It is also used to differentiate between the two types of witness programs (P2WPKH and P2WSH) by using the length of the hash (see below).
====
===== Differentiating between P2WPKH and P2WSH
In the previous two sections, we demonstrated two types of witness programs: <<p2wpkh>> and <<p2wsh>>. Both types of witness programs consist of a single byte version number followed by a longer hash. They look very similar, but are interpreted very differently: one is interpreted as a public key hash, which is satisfied by a signature and the other as a script hash, which is satisfied by a redeem script. The critical difference between them is the length of the hash:

4
ch10.asciidoc
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@ -19,7 +19,7 @@ Miners validate new transactions and record them on the global ledger. A new blo
The process is called mining because the reward (new coin generation) is designed to simulate diminishing returns, just like mining for precious metals. Bitcoin's money supply is created through mining, similar to how a central bank issues new money by printing bank notes. The maximum amount of newly created bitcoin a miner can add to a block decreases approximately every four years (or precisely every 210,000 blocks). It started at 50 bitcoin per block in January of 2009 and halved to 25 bitcoin per block in November of 2012. It halved to 12.5 bitcoin in July 2016 and again to 6.25 bitcoin in May 2020. Based on this formula, bitcoin mining rewards decrease exponentially until approximately the year 2140, when all bitcoin (20.99999998 million) will have been issued. After 2140, no new bitcoin will be issued.
Bitcoin miners also earn fees from transactions. Every transaction may include a transaction fee, in the form of a surplus of bitcoin between the transaction's inputs and outputs. The winning bitcoin miner gets to "keep the change" on the transactions included in the winning block. Today, the fees represent 0.5% or less of a bitcoin miner's income, the vast majority coming from the newly minted bitcoin. However, as the block reward decreases over time and the number of transactions per block increases, a greater proportion of bitcoin mining earnings will come from fees. Gradually, the mining reward will be dominated by transaction fees, which will form the primary incentive for miners. After 2140, the amount of new bitcoin in each block drops to zero and bitcoin mining will be incentivized only by transaction fees.
Bitcoin miners also earn fees from transactions. Every transaction usually includes a transaction fee, in the form of a surplus of bitcoin between the transaction's inputs and outputs. The winning bitcoin miner gets to "keep the change" on the transactions included in the winning block. Today, the fees represent 0.5% or less of a bitcoin miner's income, the vast majority coming from the newly minted bitcoin. However, as the reward decreases over time and the number of transactions per block increases, a greater proportion of bitcoin mining earnings will come from fees. Gradually, the mining reward will be dominated by transaction fees, which will form the primary incentive for miners. After 2140, the amount of new bitcoin in each block drops to zero and bitcoin mining will be incentivized only by transaction fees.
In this chapter, we will first examine mining as a monetary supply mechanism and then look at the most important function of mining: the decentralized consensus mechanism that underpins bitcoin's security.
@ -638,7 +638,7 @@ switching back to hexadecimal:
</ul>
++++
This means that a valid block for height 277,316 is one that has a block header hash that is less than the target. In binary that number must have more than 60 leading bits set to zero. With this level of difficulty, a single miner processing 1 trillion hashes per second (1 terahash per second or 1 TH/sec) would only find a solution once every 8,496 blocks or once every 59 days, on average.
This means that a valid block for height 277,316 is one that has a block header hash that is less than this target. In binary that number must have more than 60 leading bits set to zero. With this level of difficulty, a single miner processing 1 trillion hashes per second (1 terahash per second or 1 TH/sec) would only find a solution once every 8,496 blocks or once every 59 days, on average.
[[target]]
==== Retargeting to Adjust Difficulty

2
preface.asciidoc
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@ -132,7 +132,7 @@ link:$$https://facebook.com/AndreasMAntonopoulos$$[]
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