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Merge branch 'master' into develop
This commit is contained in:
Andreas M. Antonopoulos
commit
51883a5b74
@ -15,7 +15,7 @@ _satoshin@gmx.com_
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pass:[<a href="https://bitcoin.org/en/" class="orm:hideurl"><em>www.bitcoin.org</em></a>]
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*Abstract.* A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without going through a financial institution. Digital signatures provide part of the solution, but the main benefits are lost if a trusted third party is still required to prevent double-spending. We propose a solution to the double-spending problem using a peer-to-peer network. The network timestamps transactions by hashing them into an ongoing chain of hash-based proof-of-work, forming a record that cannot be changed without redoing the proof-of-work. The longest chain not only serves as proof of the sequence of events witnessed, but proof that it came from the largest pool of CPU power. As long as a majority of CPU power is controlled by nodes that are not cooperating to attack the network, they'11 generate the longest chain and outpace attackers. The network itself requires minimal structure. Messages are broadcast on a best effort basis, and nodes can leave and rejoin the network at will, accepting the longest proof-of-work chain as proof of what happened while they were gone.
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*Abstract.* A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without going through a financial institution. Digital signatures provide part of the solution, but the main benefits are lost if a trusted third party is still required to prevent double-spending. We propose a solution to the double-spending problem using a peer-to-peer network. The network timestamps transactions by hashing them into an ongoing chain of hash-based proof-of-work, forming a record that cannot be changed without redoing the proof-of-work. The longest chain not only serves as proof of the sequence of events witnessed, but proof that it came from the largest pool of CPU power. As long as a majority of CPU power is controlled by nodes that are not cooperating to attack the network, they'll generate the longest chain and outpace attackers. The network itself requires minimal structure. Messages are broadcast on a best effort basis, and nodes can leave and rejoin the network at will, accepting the longest proof-of-work chain as proof of what happened while they were gone.
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==== Introduction
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Commerce on the Internet has come to rely almost exclusively on financial institutions serving as trusted third parties to process electronic payments. While the system works well enough for most transactions, it still suffers from the inherent weaknesses of the trust based model. Completely non-reversible transactions are not really possible, since financial institutions cannot avoid mediating disputes. The cost of mediation increases transaction costs, limiting the minimum practical transaction size and cutting off the possibility for small casual transactions, and there is a broader cost in the loss of ability to make non-reversible payments for nonreversible services. With the possibility of reversal, the need for trust spreads. Merchants must be wary of their customers, hassling them for more information than they would otherwise need. A certain percentage of fraud is accepted as unavoidable. These costs and payment uncertainties can be avoided in person by using physical currency, but no mechanism exists to make payments over a communications channel without a trusted party.
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@ -329,7 +329,8 @@ Dogecoin address : DFpN6QqFfUm3gKNaxN6tNcab1FArL9cZLE
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==== Transaction Utility (TX)
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((("transaction utility (TX)", id="TX18")))The command-line utility +tx+ will display transactions in human-readable form, fetch base transactions from pycoin's transaction cache or from web services (pass:[<a href="https://blockchain.info/" class="orm:hideurl"><em>blockchain.info</em></a> and <a href="https://www.biteasy.com/" class="orm:hideurl"><em>biteasy.com</em></a>] are currently supported), merge transactions, add or delete inputs or outputs, and sign transactions.
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((("transaction utility (TX)", id="TX18")))
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The command-line utility +tx+ will display transactions in human-readable form, fetch base transactions from pycoin's transaction cache or from web services (blockchain.info, blockcypher.com, blockr.io and chain.so are currently supported), merge transactions, add or delete inputs or outputs, and sign transactions.
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Following are some examples.
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@ -340,7 +341,7 @@ View the famous "pizza" transaction:
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----
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$ tx 49d2adb6e476fa46d8357babf78b1b501fd39e177ac7833124b3f67b17c40c2a
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warning: consider setting environment variable PYCOIN_CACHE_DIR=~/.pycoin_cache to cache transactions fetched via web services
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warning: no service providers found for get_tx; consider setting environment variable PYCOIN_SERVICE_PROVIDERS=BLOCKR_IO:BLOCKCHAIN_INFO:BITEASY:BLOCKEXPLORER
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warning: no service providers found for get_tx; consider setting environment variable PYCOIN_BTC_PROVIDERS
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usage: tx [-h] [-t TRANSACTION_VERSION] [-l LOCK_TIME] [-n NETWORK] [-a]
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[-i address] [-f path-to-private-keys] [-g GPG_ARGUMENT]
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[--remove-tx-in tx_in_index_to_delete]
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@ -357,8 +358,8 @@ Oops! We don't have web services set up. Let's do that now:
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[source,bash]
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----
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$ PYCOIN_CACHE_DIR=~/.pycoin_cache
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$ PYCOIN_SERVICE_PROVIDERS=BLOCKR_IO:BLOCKCHAIN_INFO:BITEASY:BLOCKEXPLORER
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$ export PYCOIN_CACHE_DIR PYCOIN_SERVICE_PROVIDERS
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$ PYCOIN_BTC_PROVIDERS="block.io blockchain.info blockexplorer.com"
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$ export PYCOIN_CACHE_DIR PYCOIN_BTC_PROVIDERS
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----
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@ -10,7 +10,7 @@ In the context of bitcoin, a digital signature is _one type of witness_, but a w
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Before segwit’s introduction, every input in a transaction was followed by the witness data that unlocked it. The witness data was embedded in the transaction as part of each input. The term _segregated witness_, or _segwit_ for short, simply means separating the signature or unlocking script of a specific output. Think "separate scriptSig," or “separate signature” in the simplest form.
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Segregated Witness therefore is an architectural change to bitcoin that aims to move the witness data from the +scriptSig+ (unlocking script) field of a transaction into a separate a _witness_ data structure that accompanies a transaction. Clients may request transaction data with or without the accompanying witness data.
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Segregated Witness therefore is an architectural change to bitcoin that aims to move the witness data from the +scriptSig+ (unlocking script) field of a transaction into a separate _witness_ data structure that accompanies a transaction. Clients may request transaction data with or without the accompanying witness data.
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In this section we will look at some of the benefits of Segregated Witness, describe the mechanism used to deploy and implement this architecture change, and demonstrate the use of Segregated Witness in transactions and addresses.
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@ -236,7 +236,7 @@ Finally, the P2SH script is converted to a P2SH bitcoin address:
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37Lx99uaGn5avKBxiW26HjedQE3LrDCZru
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----
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Now, Bob can display this address for customers to pay for their coffee. Alice's wallet can make a payment to +3deadbeef+, just as it would to any other bitcoin address. Even though Alice's wallet has no support for segwit, the payment it creates can be spent by Bob with a segwit transaction.((("", startref="aliced")))
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Now, Bob can display this address for customers to pay for their coffee. Alice's wallet can make a payment to +37Lx99uaGn5avKBxiW26HjedQE3LrDCZru+, just as it would to any other bitcoin address. Even though Alice's wallet has no support for segwit, the payment it creates can be spent by Bob with a segwit transaction.((("", startref="aliced")))
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===== Pay-to-Witness-Script-Hash inside Pay-to-Script-Hash
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@ -26,6 +26,7 @@
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"appdx-bitcore.asciidoc",
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"appdx-pycoin.asciidoc",
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"appdx-bx.asciidoc",
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"glossary.asciidoc",
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"ix.html",
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"author_bio.html",
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"colo.html"
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@ -10,7 +10,7 @@ Users can transfer bitcoin over the network to do just about anything that can b
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Unlike traditional currencies, bitcoin are entirely virtual. There are no physical coins or even digital coins per se. The coins are implied in transactions that transfer value from sender to recipient. Users of bitcoin own keys that allow them to prove ownership of bitcoin in the bitcoin network. With these keys they can sign transactions to unlock the value and spend it by transferring it to a new owner. Keys are often stored in a digital wallet on each user’s computer or smartphone. Possession of the key that can sign a transaction is the only prerequisite to spending bitcoin, putting the control entirely in the hands of each user.
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Bitcoin is a distributed, peer-to-peer system. As such there is no "central" server or point of control. Bitcoin are created through a process called "mining," which involves competing to find solutions to a mathematical problem while processing bitcoin transactions. Any participant in the bitcoin network (i.e., anyone using a device running the full bitcoin protocol stack) may operate as a miner, using their computer's processing power to verify and record transactions. Every 10 minutes, on average, someone is able to validate the transactions of the past 10 minutes and is rewarded with brand new bitcoin. Essentially, bitcoin mining decentralizes the currency-issuance and clearing functions of a central bank and replaces the need for any central bank.
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Bitcoin is a distributed, peer-to-peer system. As such there is no "central" server or point of control. Bitcoin are created through a process called "mining," which involves competing to find solutions to a mathematical problem while processing bitcoin transactions. Any participant in the bitcoin network (i.e., anyone using a device running the full bitcoin protocol stack) may operate as a miner, using their computer's processing power to verify and record transactions. Every 10 minutes, on average, a bitcoin miner is able to validate the transactions of the past 10 minutes and is rewarded with brand new bitcoin. Essentially, bitcoin mining decentralizes the currency-issuance and clearing functions of a central bank and replaces the need for any central bank.
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The bitcoin protocol includes built-in algorithms that regulate the mining function across the network. The difficulty of the processing task that miners must perform is adjusted dynamically so that, on average, someone succeeds every 10 minutes regardless of how many miners (and how much processing) are competing at any moment. The protocol also halves the rate at which new bitcoin are created every 4 years, and limits the total number of bitcoin that will be created to a fixed total just below 21 million coins. The result is that the number of bitcoin in circulation closely follows an easily predictable curve that approaches 21 million by the year 2140. Due to bitcoin's diminishing rate of issuance, over the long term, the bitcoin currency is deflationary. Furthermore, bitcoin cannot be inflated by "printing" new money above and beyond the expected issuance rate.
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@ -47,7 +47,7 @@ When cryptography started becoming more broadly available and understood in the
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((("Nakamoto, Satoshi")))((("distributed computing")))((("bitcoin", "history of")))Bitcoin was invented in 2008 with the publication of a paper titled "Bitcoin: A Peer-to-Peer Electronic Cash System,"footnote:["Bitcoin: A Peer-to-Peer Electronic Cash System," Satoshi Nakamoto (https://bitcoin.org/bitcoin.pdf).] written under the alias of Satoshi Nakamoto (see <<satoshi_whitepaper>>). Nakamoto combined several prior inventions such as b-money and HashCash to create a completely decentralized electronic cash system that does not rely on a central authority for currency issuance or settlement and validation of transactions. ((("Proof-of-Work algorithm")))((("decentralized systems", "consensus in")))((("mining and consensus", "Proof-of-Work algorithm")))The key innovation was to use a distributed computation system (called a "Proof-of-Work" algorithm) to conduct a global "election" every 10 minutes, allowing the decentralized network to arrive at _consensus_ about the state of transactions. ((("double-spend problem")))((("spending bitcoin", "double-spend problem")))This elegantly solves the issue of double-spend where a single currency unit can be spent twice. Previously, the double-spend problem was a weakness of digital currency and was addressed by clearing all transactions through a central clearinghouse.
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The bitcoin network started in 2009, based on a reference implementation published by Nakamoto and since revised by many other programmers. The implementation of the Proof-of-Work algorithm (mining) that provides security and resilience for bitcoin has increased in power exponentially, and now exceeds the combined processing power of the world's top supercomputers. Bitcoin's total market value has at times exceeded $20 billion US dollars, depending on the bitcoin-to-dollar exchange rate. The largest transaction processed so far by the network was $150 million US dollars, transmitted instantly and processed without any fees.
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The bitcoin network started in 2009, based on a reference implementation published by Nakamoto and since revised by many other programmers. The implementation of the Proof-of-Work algorithm (mining) that provides security and resilience for bitcoin has increased in power exponentially, and now exceeds the combined processing power of the world's top supercomputers. Bitcoin's total market value has at times exceeded $35 billion US dollars, depending on the bitcoin-to-dollar exchange rate. The largest transaction processed so far by the network was $150 million US dollars, transmitted instantly and processed without any fees.
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Satoshi Nakamoto withdrew from the public in April 2011, leaving the responsibility of developing the code and network to a thriving group of volunteers. The identity of the person or people behind bitcoin is still unknown. ((("open source licenses")))However, neither Satoshi Nakamoto nor anyone else exerts individual control over the bitcoin system, which operates based on fully transparent mathematical principles, open source code, and consensus among participants. The invention itself is groundbreaking and has already spawned new science in the fields of distributed computing, economics, and econometrics.
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@ -182,7 +182,7 @@ In addition to these various sites and applications, most bitcoin wallets will a
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==== Sending and Receiving Bitcoin
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((("getting started", "sending and receiving bitcoin", id="GSsend01")))((("spending bitcoin", "bitcoin wallet quick start example")))((("spending bitcoin", see="also transactions")))Alice has decided to convert $10 US dollars into bitcoin, so as not to risk too much money on this new technology. She gives Joe $10 in cash, opens her Mycelium wallet application, and selects Receive. This displays a QR code with Alice's first bitcoin address.
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((("getting started", "sending and receiving bitcoin", id="GSsend01")))((("spending bitcoin", "bitcoin wallet quick start example")))((("spending bitcoin", see="also transactions")))Alice has decided to exchange $10 US dollars for bitcoin, so as not to risk too much money on this new technology. She gives Joe $10 in cash, opens her Mycelium wallet application, and selects Receive. This displays a QR code with Alice's first bitcoin address.
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Joe then selects Send on his smartphone wallet and is presented with a screen containing two inputs:
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@ -208,5 +208,3 @@ Meanwhile, Alice's wallet is constantly "listening" to published transactions on
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****
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Alice is now the proud owner of 0.10 BTC that she can spend. In the next chapter we will look at her first purchase with bitcoin, and examine the underlying transaction and propagation technologies in more detail.((("", startref="BCbasic01")))((("use cases", "buying coffee", startref="aliceone")))
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@ -609,7 +609,7 @@ d50f654e788acd0ef8000000000001976a9147f9b1a7fb68d60c536c2fd8aeaa53a8f3cc025a8&#x
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</pre>
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++++
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The transaction decode shows all the components of this transaction, including the transaction inputs and outputs. In this case we see that the transaction that credited our new address with 50 millibits used one input and generated two outputs. The input to this transaction was the output from a previously confirmed transaction (shown as the vin txid starting with +7957a35fe+). The two outputs correspond to the 50 millibit credit and an output with change back to the sender.
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The transaction decode shows all the components of this transaction, including the transaction inputs and outputs. In this case we see that the transaction that credited our new address with 15 millibits used one input and generated two outputs. The input to this transaction was the output from a previously confirmed transaction (shown as the vin txid starting with +7957a35fe+). The two outputs correspond to the 15 millibit credit and an output with change back to the sender.
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We can further explore the blockchain by examining the previous transaction referenced by its txid in this transaction using the same commands (e.g., +getrawtransaction+). Jumping from transaction to transaction we can follow a chain of transactions back as the coins are transmitted from owner address to owner address.
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@ -299,7 +299,7 @@ There is also a BIP-39 generator implemented in a standalone webpage, which is e
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.A BIP-39 generator as a standalone web page
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image::images/mbc2_0508.png["BIP-39 generator web-page"]
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((("", startref="mnemonic05")))((("", startref="BIP3905")))The page can be used offline in a browser, or https://dcpos.github.io/bip39/[accessed online].
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((("", startref="mnemonic05")))((("", startref="BIP3905")))The page ( https://iancoleman.github.io/bip39/) can be used offline in a browser, or accessed online.
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==== Creating an HD Wallet from the Seed
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@ -333,7 +333,7 @@ The chain code is used to introduce deterministic random data to the process, so
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These three items (parent key, chain code, and index) are combined and hashed to generate children keys, as follows.
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The parent public key, chain code, and the index number are combined and hashed with the HMAC-SHA512 algorithm to produce a 512-bit hash. This 512-bit hash is split into two 256-bit halves. The right-half 256 bits of the hash output become the chain code for the child. The left-half 256 bits of the hash and the index number are added to the parent private key to produce the child private key. In <<CKDpriv>>, we see this illustrated with the index set to 0 to produce the "zero" (first by index) child of the parent.
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The parent public key, chain code, and the index number are combined and hashed with the HMAC-SHA512 algorithm to produce a 512-bit hash. This 512-bit hash is split into two 256-bit halves. The right-half 256 bits of the hash output become the chain code for the child. The left-half 256 bits of the hash are added to the parent private key to produce the child private key. In <<CKDpriv>>, we see this illustrated with the index set to 0 to produce the "zero" (first by index) child of the parent.
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[[CKDpriv]]
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.Extending a parent private key to create a child private key
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@ -70,7 +70,7 @@ You may also notice a lot of strange and indecipherable fields and hexadecimal s
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((("change, making")))If an UTXO is larger than the desired value of a transaction, it must still be consumed in its entirety and change must be generated in the transaction. In other words, if you have a UTXO worth 20 bitcoin and want to pay only 1 bitcoin, your transaction must consume the entire 20-bitcoin UTXO and produce two outputs: one paying 1 bitcoin to your desired recipient and another paying 19 bitcoin in change back to your wallet. As a result of the indivisible nature of transaction outputs, most bitcoin transactions will have to generate change.
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Imagine a shopper buying a $1.50 beverage, reaching into her wallet and trying to find a combination of coins and bank notes to cover the $1.50 cost. The shopper will choose exact change if available (e.g., a dollar bill and two quarters), or a combination of smaller denominations (six quarters), or if necessary, a larger unit such as a $5 note. If she hands too much money, say $5, to the shop owner, she will expect $3.50 change, which she will return to her wallet and have available for future transactions.
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Imagine a shopper buying a $1.50 beverage, reaching into her wallet and trying to find a combination of coins and bank notes to cover the $1.50 cost. The shopper will choose exact change if available e.g. a dollar bill and two quarters (a quarter is $0.25), or a combination of smaller denominations (six quarters), or if necessary, a larger unit such as a $5 note. If she hands too much money, say $5, to the shop owner, she will expect $3.50 change, which she will return to her wallet and have available for future transactions.
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Similarly, a bitcoin transaction must be created from a user's UTXO in whatever denominations that user has available. Users cannot cut an UTXO in half any more than they can cut a dollar bill in half and use it as currency. The user's wallet application will typically select from the user's available UTXO to compose an amount greater than or equal to the desired transaction amount.
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@ -507,7 +507,7 @@ image::images/mbc2_0606.png["Tx_Script_P2PubKeyHash_2"]
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((("digital signatures", "algorithm used")))((("Elliptic Curve Digital Signature Algorithm (ECDSA)")))The digital signature algorithm used in bitcoin is the _Elliptic Curve Digital Signature Algorithm_, or _ECDSA_. ECDSA is the algorithm used for digital signatures based on elliptic curve private/public key pairs, as described in <<elliptic_curve>>. ECDSA is used by the script functions +OP_CHECKSIG+, +OP_CHECKSIGVERIFY+, +OP_CHECKMULTISIG+, and +OP_CHECKMULTISIGVERIFY+. Any time you see those in a locking script, the unlocking script must contain an ECDSA signature.
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((("digital signatures", "purposes of")))A digital signature serves three purposes in bitcoin (see the following sidebar). First, the signature proves that the owner of the private key, who is by implication the owner of the funds, has _authorized_ the spending of those funds. Secondly, the proof of authorization is _undeniable_ (nonrepudiation). Thirdly, the signature proves that the transaction (or specific parts of the transaction) have not and _cannot be modified_ by anyone after it has been been signed.
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((("digital signatures", "purposes of")))A digital signature serves three purposes in bitcoin (see the following sidebar). First, the signature proves that the owner of the private key, who is by implication the owner of the funds, has _authorized_ the spending of those funds. Secondly, the proof of authorization is _undeniable_ (nonrepudiation). Thirdly, the signature proves that the transaction (or specific parts of the transaction) have not and _cannot be modified_ by anyone after it has been signed.
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Note that each transaction input is signed independently. This is critical, as neither the signatures nor the inputs have to belong to or be applied by the same "owners." In fact, a specific transaction scheme called "CoinJoin" uses this fact to create multi-party transactions for privacy.
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@ -149,7 +149,7 @@ If there is no traffic on a connection, nodes will periodically send a message t
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((("blocks", "genesis block")))((("genesis block")))((("blockchain (the)", "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.
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((("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.
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((("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 more than one hundred 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.
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((("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 75% 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/+.
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@ -197,7 +197,7 @@ image::images/mbc2_0903.png["merkle_tree_odd"]
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The same method for constructing a tree from four transactions can be generalized to construct trees of any size. In bitcoin it is common to have several hundred to more than a thousand transactions in a single block, which are summarized in exactly the same way, producing just 32 bytes of data as the single merkle root. In <<merkle_tree_large>>, you will see a tree built from 16 transactions. Note that although the root looks bigger than the leaf nodes in the diagram, it is the exact same size, just 32 bytes. Whether there is one transaction or a hundred thousand transactions in the block, the merkle root always summarizes them into 32 bytes.
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((("authentication paths")))To prove that a specific transaction is included in a block, a node only needs to produce +log~2~(N)+ 32-byte hashes, constituting an _authentication path_ or _merkle path_ connecting the specific transaction to the root of the tree. This is especially important as the number of transactions increases, because the base-2 logarithm of the number of transactions increases much more slowly. This allows bitcoin nodes to efficiently produce paths of 10 or 12 hashes (320–384 bytes), which can provide proof of a single transaction out of more than a thousand transactions in a megabyte-size block.
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((("authentication paths")))To prove that a specific transaction is included in a block, a node only needs to produce +log~2~(N)+ 32-byte hashes, constituting an _authentication path_ or _merkle path_ connecting the specific transaction to the root of the tree. This is especially important as the number of transactions increases, because the base-2 logarithm of the number of transactions increases much more slowly. This allows bitcoin nodes to efficiently produce paths of 10 or 12 hashes (320–384 bytes), which can provide proof of a single transaction out of more than a thousand transactions in a megabyte-sized block.
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[[merkle_tree_large]]
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.A merkle tree summarizing many data elements
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@ -281,7 +281,7 @@ The initial subsidy is calculated in satoshis by multiplying 50 with the +COIN+
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The maximum number of halvings allowed is 64, so the code imposes a zero reward (returns only the fees) if the 64 halvings is exceeded.
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Next, the function uses the binary-right-shift operator to divide the reward (+nSubsidy+) by two for each round of halving. In the case of block 277,316, this would binary-right-shift the reward of 5 billion satoshis once (one halving) and result in 2.5 billion satoshis, or 25 bitcoin. The binary-right-shift operator is used because it is more efficient for division by two than integer or floating-point division.
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Next, the function uses the binary-right-shift operator to divide the reward (+nSubsidy+) by two for each round of halving. In the case of block 277,316, this would binary-right-shift the reward of 5 billion satoshis once (one halving) and result in 2.5 billion satoshis, or 25 bitcoins. The binary-right-shift operator is used because it is more efficient than multiple repeated divisions. To avoid a potential bug, the shift operation is skipped after 63 halvings, and the subsidy is set to 0.
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Finally, the coinbase reward (+nSubsidy+) is added to the transaction fees (+nFees+), and the sum is returned.
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|
||||
@ -701,10 +701,10 @@ The difficulty of mining is closely related to the cost of electricity and the e
|
||||
|
||||
((("mining and consensus", "mining the block", "successful completion")))((("use cases", "mining for bitcoin", id="jingtentwo")))As we saw earlier, Jing's node has constructed a candidate block and prepared it for mining. Jing has several hardware mining rigs with application-specific integrated circuits, where hundreds of thousands of integrated circuits run the SHA256 algorithm in parallel at incredible speeds. Many of these specialized machines are connected to his mining node over USB or a local area network. Next, the mining node running on Jing's desktop transmits the block header to his mining hardware, which starts testing trillions of nonces per second.
|
||||
|
||||
Almost 11 minutes after starting to mine block 277,316, one of the hardware mining machines finds a solution and sends it back to the mining node. When inserted into the block header, the nonce 4,215,469,401 produces a block hash of:
|
||||
Almost 11 minutes after starting to mine block 277,316, one of the hardware mining machines finds a solution and sends it back to the mining node. When inserted into the block header, the nonce 924,591,752 produces a block hash of:
|
||||
|
||||
----
|
||||
0000000000000002a7bbd25a417c0374cc55261021e8a9ca74442b01284f0569
|
||||
0000000000000001b6b9a13b095e96db41c4a928b97ef2d944a9b31b2cc7bdc4
|
||||
----
|
||||
|
||||
which is less than the target:
|
||||
@ -773,14 +773,14 @@ image::images/mbc2_1002.png["Before the fork - all nodes have the same perspecti
|
||||
|
||||
A "fork" occurs whenever there are two candidate blocks competing to form the longest blockchain. This occurs under normal conditions whenever two miners solve the Proof-of-Work algorithm within a short period of time from each other. As both miners discover a solution for their respective candidate blocks, they immediately broadcast their own "winning" block to their immediate neighbors who begin propagating the block across the network. Each node that receives a valid block will incorporate it into its blockchain, extending the blockchain by one block. If that node later sees another candidate block extending the same parent, it connects the second candidate on a secondary chain. As a result, some nodes will "see" one candidate block first, while other nodes will see the other candidate block and two competing versions of the blockchain will emerge.
|
||||
|
||||
In <<fork2>>, we see two miners (Node A and Node B) who mine two different blocks almost simultaneously. Both of these blocks are children of the star block, and extend the chain by building on top of the star block. To help us track it, one is visualized as a triangle block originating from Node A, and the other is shown as an upside-down triangle block originating from Node B.
|
||||
In <<fork2>>, we see two miners (Node X and Node Y) who mine two different blocks almost simultaneously. Both of these blocks are children of the star block, and extend the chain by building on top of the star block. To help us track it, one is visualized as a triangle block originating from Node X, and the other is shown as an upside-down triangle block originating from Node Y.
|
||||
|
||||
[[fork2]]
|
||||
[role="smallersixty"]
|
||||
.Visualization of a blockchain fork event: two blocks found simultaneously
|
||||
image::images/mbc2_1003.png["Visualization of a blockchain fork event: two blocks found simultaneously"]
|
||||
|
||||
Let's assume, for example, that a miner Node A finds a Proof-of-Work solution for a block "triangle" that extends the blockchain, building on top of the parent block "star." Almost simultaneously, the miner Node B who was also extending the chain from block "star" finds a solution for block "upside-down triangle," his candidate block. Now, there are two possible blocks; one we call "triangle," originating in Node A; and one we call "upside-down triangle," originating in Node B. Both blocks are valid, both blocks contain a valid solution to the Proof-of-Work, and both blocks extend the same parent (block "star"). Both blocks likely contain most of the same transactions, with only perhaps a few differences in the order of transactions.
|
||||
Let's assume, for example, that a miner Node X finds a Proof-of-Work solution for a block "triangle" that extends the blockchain, building on top of the parent block "star." Almost simultaneously, the miner Node Y who was also extending the chain from block "star" finds a solution for block "upside-down triangle," his candidate block. Now, there are two possible blocks; one we call "triangle," originating in Node X; and one we call "upside-down triangle," originating in Node Y. Both blocks are valid, both blocks contain a valid solution to the Proof-of-Work, and both blocks extend the same parent (block "star"). Both blocks likely contain most of the same transactions, with only perhaps a few differences in the order of transactions.
|
||||
|
||||
As the two blocks propagate, some nodes receive block "triangle" first and some receive block "upside-down triangle" first. As shown in <<fork3>>, the network splits into two different perspectives of the blockchain; one side topped with a triangle block, the other with the upside-down-triangle block.
|
||||
|
||||
@ -822,7 +822,7 @@ Bitcoin's block interval of 10 minutes is a design compromise between fast confi
|
||||
|
||||
((("mining and consensus", "hashing power race", id="MAChash10")))Bitcoin mining is an extremely competitive industry. The hashing power has increased exponentially every year of bitcoin's existence. Some years the growth has reflected a complete change of technology, such as in 2010 and 2011 when many miners switched from using CPU mining to GPU mining and field programmable gate array (FPGA) mining. In 2013 the introduction of ASIC mining lead to another giant leap in mining power, by placing the SHA256 function directly on silicon chips specialized for the purpose of mining. The first such chips could deliver more mining power in a single box than the entire bitcoin network in 2010.
|
||||
|
||||
The following list shows the total hashing power of the bitcoin network, over the first five years of operation:
|
||||
The following list shows the total hashing power of the bitcoin network, over the first eight years of operation:
|
||||
|
||||
2009:: 0.5 MH/sec–8 MH/sec (16× growth)
|
||||
2010:: 8 MH/sec–116 GH/sec (14,500× growth)
|
||||
@ -857,7 +857,7 @@ In the last two years, the ASIC mining chips have become increasingly denser, ap
|
||||
|
||||
((("mining pools", id="MACoverpool10")))((("mining pools", "benefits of")))In this highly competitive environment, individual miners working alone (also known as solo miners) don't stand a chance. The likelihood of them finding a block to offset their electricity and hardware costs is so low that it represents a gamble, like playing the lottery. Even the fastest consumer ASIC mining system cannot keep up with commercial systems that stack tens of thousands of these chips in giant warehouses near hydroelectric powerstations. Miners now collaborate to form mining pools, pooling their hashing power and sharing the reward among thousands of participants. By participating in a pool, miners get a smaller share of the overall reward, but typically get rewarded every day, reducing uncertainty.
|
||||
|
||||
Let's look at a specific example. Assume a miner has purchased mining hardware with a combined hashing rate of 14,000 gigahashes per second (GH/s), or 14 TH/s. In 2017 this equipment costs approximately $2,500 USD. The hardware consumes 1375 watts (1.3 kW) of electricity when running, 32 kW-hours a day, at a cost of $1 to $2 per day at very low electricity rates. At current bitcoin difficulty, the miner will be able to solo mine a block approximately once every 4 years. If the miner does find a single block in that timeframe, the payout of 12.5 bitcoin, at approximately $1,000 per bitcoin, will result in a single payout of $12,500, which will not even cover the entire cost of the hardware and the electricity consumed over the time period, leaving a net loss of approximately $1,000. However, the chance of finding a block in a 4-year period depends on the miner's luck. He might find two blocks in 4 years and make a very large profit. Or he might not find a block for 5 years and suffer a bigger financial loss. Even worse, the difficulty of the bitcoin Proof-of-Work algorithm is likely to go up significantly over that period, at the current rate of growth of hashing power, meaning the miner has, at most, one year to break even before the hardware is effectively obsolete and must be replaced by more powerful mining hardware. If this miner participates in a mining pool, instead of waiting for a once-in-four-years $12,500 windfall, he will be able to earn approximately $50 to $60 per week. The regular payouts from a mining pool will help him amortize the cost of hardware and electricity over time without taking an enormous risk. The hardware will still be obsolete in one or two years and the risk is still high, but the revenue is at least regular and reliable over that period. Financially this only makes sense at very low electricity cost (less than 1 cent per kW) and only at very large scale.
|
||||
Let's look at a specific example. Assume a miner has purchased mining hardware with a combined hashing rate of 14,000 gigahashes per second (GH/s), or 14 TH/s. In 2017 this equipment costs approximately $2,500 USD. The hardware consumes 1375 watts (1.3 kW) of electricity when running, 32 kW-hours a day, at a cost of $1 to $2 per day at very low electricity rates. At current bitcoin difficulty, the miner will be able to solo mine a block approximately once every 4 years. If the miner does find a single block in that timeframe, the payout of 12.5 bitcoin, at approximately $1,000 per bitcoin, will result in a single payout of $12,500, which will not even cover the entire cost of the hardware and the electricity consumed over the time period, leaving a net loss of approximately $1,000. However, the chance of finding a block in a 4-year period depends on the miner's luck. He might find two blocks in 4 years and make a very large profit. Or he might not find a block for 5 years and suffer a bigger financial loss. Even worse, the difficulty of the bitcoin Proof-of-Work algorithm is likely to go up significantly over that period, at the current rate of growth of hashing power, meaning the miner has, at most, one year to break even before the hardware is effectively obsolete and must be replaced by more powerful mining hardware. If this miner participates in a mining pool, instead of waiting for a once-in-four-years $12,500 windfall, he will be able to earn approximately $50 to $60 per week. The regular payouts from a mining pool will help him amortize the cost of hardware and electricity over time without taking an enormous risk. The hardware will still be obsolete in one or two years and the risk is still high, but the revenue is at least regular and reliable over that period. Financially this only makes sense at very low electricity cost (less than 1 cent per kW-hour) and only at very large scale.
|
||||
|
||||
Mining pools coordinate many hundreds or thousands of miners, over specialized pool-mining protocols. The individual miners configure their mining equipment to connect to a pool server, after creating an account with the pool. Their mining hardware remains connected to the pool server while mining, synchronizing their efforts with the other miners. Thus, the pool miners share the effort to mine a block and then share in the rewards.
|
||||
|
||||
|
||||
@ -293,7 +293,7 @@ The refund transaction acts as the first commitment transaction and its timelock
|
||||
|
||||
Now that Emma has a fully signed refund transaction, she can confidently transmit the signed funding transaction knowing that she can eventually, after the timelock expires, redeem the refund transaction even if Fabian disappears.
|
||||
|
||||
Every commitment transaction the parties exchange during the life of the channel will be timelocked into the future. But the delay will be slightly shorter for each commitment so the most recent commitment can be redeemed before the prior commitment it invalidates. Because of the +nLocktime+, neither party can successfully propagate any of the commitment transactions until their timelock expires. If all goes well, they will cooperate and close the channel gracefully with a settlement transaction, making it unnecessary to transmit an intermediate commitment transaction. In essence, the commitment transactions are only used when one party disconnects and the other party has to close the channel unilaterally.
|
||||
Every commitment transaction the parties exchange during the life of the channel will be timelocked into the future. But the delay will be slightly shorter for each commitment so the most recent commitment can be redeemed before the prior commitment it invalidates. Because of the nLockTime, neither party can successfully propagate any of the commitment transactions until their timelock expires. If all goes well, they will cooperate and close the channel gracefully with a settlement transaction, making it unnecessary to transmit an intermediate commitment transaction. If not, the most recent commitment transaction can be propagated to settle the account and invalidate all prior commitment transactions.
|
||||
|
||||
For example, if commitment transaction #1 is timelocked to 4320 blocks in the future, then commitment transaction #2 is timelocked to 4319 blocks in the future. Commitment transaction #600 can be spent 600 blocks before commitment transaction #1 becomes valid.
|
||||
|
||||
|
||||
@ -2,23 +2,29 @@
|
||||
|
||||
int main()
|
||||
{
|
||||
// Private secret key.
|
||||
bc::ec_secret secret;
|
||||
bool success = bc::decode_base16(secret,
|
||||
// Private secret key string as base16
|
||||
bc::ec_secret decoded;
|
||||
bc::decode_base16(decoded,
|
||||
"038109007313a5807b2eccc082c8c3fbb988a973cacf1a7df9ce725c31b14776");
|
||||
assert(success);
|
||||
|
||||
bc::wallet::ec_private secret(
|
||||
decoded, bc::wallet::ec_private::mainnet_p2kh);
|
||||
|
||||
// Get public key.
|
||||
bc::ec_point public_key = bc::secret_to_public_key(secret);
|
||||
std::cout << "Public key: " << bc::encode_hex(public_key) << std::endl;
|
||||
bc::wallet::ec_public public_key(secret);
|
||||
std::cout << "Public key: " << public_key.encoded() << std::endl;
|
||||
|
||||
// Create Bitcoin address.
|
||||
// Normally you can use:
|
||||
// bc::payment_address payaddr;
|
||||
// bc::set_public_key(payaddr, public_key);
|
||||
// const std::string address = payaddr.encoded();
|
||||
// bc::wallet::payment_address payaddr =
|
||||
// public_key.to_payment_address(
|
||||
// bc::wallet::ec_public::mainnet_p2kh);
|
||||
// const std::string address = payaddr.encoded();
|
||||
|
||||
// Compute hash of public key for P2PKH address.
|
||||
const bc::short_hash hash = bc::bitcoin_short_hash(public_key);
|
||||
bc::data_chunk public_key_data;
|
||||
public_key.to_data(public_key_data);
|
||||
const auto hash = bc::bitcoin_short_hash(public_key_data);
|
||||
|
||||
bc::data_chunk unencoded_address;
|
||||
// Reserve 25 bytes
|
||||
|
||||
@ -24,10 +24,10 @@ bc::hash_digest create_merkle(bc::hash_list& merkle)
|
||||
{
|
||||
// Join both current hashes together (concatenate).
|
||||
bc::data_chunk concat_data(bc::hash_size * 2);
|
||||
auto concat = bc::make_serializer(concat_data.begin());
|
||||
auto concat = bc::serializer<
|
||||
decltype(concat_data.begin())>(concat_data.begin());
|
||||
concat.write_hash(*it);
|
||||
concat.write_hash(*(it + 1));
|
||||
assert(concat.iterator() == concat_data.end());
|
||||
// Hash both of the hashes.
|
||||
bc::hash_digest new_root = bc::bitcoin_hash(concat_data);
|
||||
// Add this to the new list.
|
||||
@ -39,7 +39,7 @@ bc::hash_digest create_merkle(bc::hash_list& merkle)
|
||||
// DEBUG output -------------------------------------
|
||||
std::cout << "Current merkle hash list:" << std::endl;
|
||||
for (const auto& hash: merkle)
|
||||
std::cout << " " << bc::encode_hex(hash) << std::endl;
|
||||
std::cout << " " << bc::encode_base16(hash) << std::endl;
|
||||
std::cout << std::endl;
|
||||
// --------------------------------------------------
|
||||
}
|
||||
@ -56,7 +56,7 @@ int main()
|
||||
bc::hash_literal("0000000000000000000000000000000000000000000000000000000000000022"),
|
||||
}};
|
||||
const bc::hash_digest merkle_root = create_merkle(tx_hashes);
|
||||
std::cout << "Result: " << bc::encode_hex(merkle_root) << std::endl;
|
||||
std::cout << "Result: " << bc::encode_base16(merkle_root) << std::endl;
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
@ -7,20 +7,19 @@
|
||||
int main()
|
||||
{
|
||||
// Create genesis block.
|
||||
const bc::block_type block = bc::genesis_block();
|
||||
bc::chain::block block = bc::chain::block::genesis_mainnet();
|
||||
// Genesis block contains a single coinbase transaction.
|
||||
assert(block.transactions.size() == 1);
|
||||
assert(block.transactions().size() == 1);
|
||||
// Get first transaction in block (coinbase).
|
||||
const bc::transaction_type& coinbase_tx = block.transactions[0];
|
||||
const bc::chain::transaction& coinbase_tx = block.transactions()[0];
|
||||
// Coinbase tx has a single input.
|
||||
assert(coinbase_tx.inputs.size() == 1);
|
||||
const bc::transaction_input_type& coinbase_input = coinbase_tx.inputs[0];
|
||||
assert(coinbase_tx.inputs().size() == 1);
|
||||
const bc::chain::input& coinbase_input = coinbase_tx.inputs()[0];
|
||||
// Convert the input script to its raw format.
|
||||
const bc::data_chunk raw_message = save_script(coinbase_input.script);
|
||||
// Convert this to an std::string.
|
||||
std::string message;
|
||||
message.resize(raw_message.size());
|
||||
std::copy(raw_message.begin(), raw_message.end(), message.begin());
|
||||
const auto prefix = false;
|
||||
const bc::data_chunk& raw_message = coinbase_input.script().to_data(prefix);
|
||||
// Convert this to a std::string.
|
||||
std::string message(raw_message.begin(), raw_message.end());
|
||||
// Display the genesis block message.
|
||||
std::cout << message << std::endl;
|
||||
return 0;
|
||||
|
||||
@ -1,3 +1,4 @@
|
||||
#include <random>
|
||||
#include <bitcoin/bitcoin.hpp>
|
||||
|
||||
// The string we are searching for
|
||||
@ -30,7 +31,7 @@ int main()
|
||||
{
|
||||
// Success!
|
||||
std::cout << "Found vanity address! " << address << std::endl;
|
||||
std::cout << "Secret: " << bc::encode_hex(secret) << std::endl;
|
||||
std::cout << "Secret: " << bc::encode_base16(secret) << std::endl;
|
||||
return 0;
|
||||
}
|
||||
}
|
||||
@ -51,11 +52,9 @@ bc::ec_secret random_secret(std::default_random_engine& engine)
|
||||
|
||||
std::string bitcoin_address(const bc::ec_secret& secret)
|
||||
{
|
||||
// Convert secret to pubkey...
|
||||
bc::ec_point pubkey = bc::secret_to_public_key(secret);
|
||||
// Finally create address.
|
||||
bc::payment_address payaddr;
|
||||
bc::set_public_key(payaddr, pubkey);
|
||||
// Convert secret to payment address
|
||||
bc::wallet::ec_private private_key(secret);
|
||||
bc::wallet::payment_address payaddr(private_key);
|
||||
// Return encoded form.
|
||||
return payaddr.encoded();
|
||||
}
|
||||
|
||||
@ -1,36 +0,0 @@
|
||||
== Colored Coins
|
||||
|
||||
The term _Colored Coins_ refers to a set of similar technologies that use bitcoin transactions to record the creation, ownership and transfer of extrinsic assets other than bitcoin. By "extrinsic" we mean assets that are not stored directly on the bitcoin blockchain, as opposed to bitcoin itself which is an asset intrinsic to the blockchain.
|
||||
|
||||
Colored coins are used to track digital assets as well as physical assets held by third parties and traded through colored coins certificates of ownership. Digital asset colored coins can represent intangible assets such as a stock certificate, license, virtual property (game items), or most any form of licensed intellectual property (trademarks, copyrights, etc). Tangible asset colored coins can represent certificates of ownership of commodities (gold, silver, oil), land title, automobiles, boats, aircraft, etc.
|
||||
|
||||
The term derives from the idea of "coloring" or marking a nominal amount of bitcoin, for example a single satoshi, to represent something other than the bitcoin value itself. As an analogy, consider stamping a $1 note with a message saying "This is a stock certificate of ACME" or "This note can be redeemed for 1 oz of silver" and then trading the $1 note as a certificate of ownership of this other asset. The first implementation of colored coins, named _Enhanced Padded-Order-Based Coloring_ or _EPOBC_ assigned extrinsic assets to a 1 satoshi output. In this way, it was a true "colored coin".
|
||||
|
||||
After _EPOBC_, more recent implementations of colored coins use the OP_RETURN script to store metadata about extrinsic assets. In a sense these systems are not true colored coins as no coins are "colored". Instead, transactions with OP_RETURN metadata are used to create and track ownership in conjunction with external data stores which associate the metadata to specific assets.
|
||||
|
||||
The two most prominent implementations of colored coins today are http://www.openassets.org/[_Open Assets_] and https://coloredcoins.org[_Colored Coins by Colu_]. These two systems use different approaches to colored coins and are not compatible. Colored coins created in one system cannot be seen or used in the other system.
|
||||
|
||||
==== Using Colored Coins
|
||||
|
||||
Colored coins are created, transfered and generally viewed in special wallets that can interpret the colored coins protocol metadata attached to bitcoin transactions. Special care must be taken to avoid using a colored coin related key in a regular bitcoin wallet, as the regular wallet may destroy the metadata. Similarly, colored coins should not be sent to addresses managed by regular wallets, but only to addresses that are managed by wallets that are colored-coin-aware. Both Colu and Open Assets systems use special colored-coin addresses to address this risk and to ensure that colored coins are not sent to unaware wallets.
|
||||
|
||||
Colored coins are also not visible to most general-purpose blockchain explorers. Instead, you must use a colored-coins explorer to interpret the metadata of a colored coins transaction.
|
||||
|
||||
Am Open Assets compatible wallet application and blockchain explorer can be found at:
|
||||
|
||||
coinprism: https://www.coinprism.info[https://www.coinprism.info]
|
||||
|
||||
A Colu Colored Coins compatible wallet application and blockchain explorer can be found at:
|
||||
|
||||
Blockchain Explorer: http://coloredcoins.org/explorer/[http://coloredcoins.org/explorer/]
|
||||
|
||||
Copay wallet plugin:
|
||||
http://coloredcoins.org/colored-coins-copay-addon/[http://coloredcoins.org/colored-coins-copay-addon/]
|
||||
|
||||
==== Creating Colored Coins
|
||||
|
||||
Each of the colored coins implementations has a different way of creating colored coins, but they all provide similar functionality. The process of creating a colored coin asset is called _issuance_. An initial transaction, the _issuance transaction_ registers the asset on the bitcoin blockchain and creates an _asset ID_ that is used to reference the asset. Once issued, assets can be transferred between addresses using _transfer transactions_.
|
||||
|
||||
Assets issued as colored coins can have multiple properties. They can be _divisible_ or _indivisible_, meaning that the amount of asset in a transfer can be an integer (eg. 5) or have decimal subdivision (eg. 4.321). Assets can also have _fixed issuance_, meaning a certain amount are issued only once, or can be _reissued_, meaning that new units of the asset can be issued by the original issuer after the initial issuance.
|
||||
|
||||
Finally, some colored coins enable the issuance of _dividends_, allowing the distribution of bitcoin payments to the owners of a colored coin asset in proportion to their ownership.
|
||||
@ -62,7 +62,7 @@ ECDSA::
|
||||
Elliptic Curve Digital Signature Algorithm or ECDSA is a cryptographic algorithm used by Bitcoin to ensure that funds can only be spent by their rightful owners.
|
||||
|
||||
Extra Nonce::
|
||||
As difficulty increased, miners often cycled through all 4 billion values of the nonce without finding a block. Because the coinbase script can store between 2 and 100 bytes of data, miners started using that space as extra nonce space, allowing them to explore a much larger range of block header values to find valid blocks. (("Extra Nonce")))
|
||||
As difficulty increased, miners often cycled through all 4 billion values of the nonce without finding a block. Because the coinbase script can store between 2 and 100 bytes of data, miners started using that space as extra nonce space, allowing them to explore a much larger range of block header values to find valid blocks.
|
||||
|
||||
fees::
|
||||
The sender of a transaction often includes a fee to the network for processing the requested transaction. Most transactions require a minimum fee of 0.5 mBTC.
|
||||
@ -183,7 +183,7 @@ Proof-of-stake::
|
||||
Proof-of-stake (PoS) is a method by which a cryptocurrency blockchain network aims to achieve distributed consensus. Proof of stake asks users to prove ownership of a certain amount of currency (their "stake" in the currency).
|
||||
|
||||
Proof-Of-Work::
|
||||
A piece of data that requires significant computation to find. In bitcoin, miners must find a numeric solution to the SHA256 algorithm that meets a network-wide target, the difficulty target.
|
||||
A piece of data that requires significant computation to find. In bitcoin, miners must find a numeric solution to the SHA256 algorithm that meets a network-wide target, the difficulty target.
|
||||
|
||||
reward::
|
||||
An amount included in each new block as a reward by the network to the miner who found the Proof-Of-Work solution. It is currently 12.5BTC per block.
|
||||
@ -191,6 +191,9 @@ reward::
|
||||
RIPEMD-160::
|
||||
RIPEMD-160 is a 160-bit cryptographic hash function. RIPEMD-160 is a strengthened version of RIPEMD with a 160-bit hash result, and is expected to be secure for the next ten years or more.
|
||||
|
||||
satoshi::
|
||||
A satoshi is the smallest denomination of bitcoin that can be recorded on the blockchain. It is the equivalent of 0.00000001 bitcoin and is named after the creator of Bitcoin, Satoshi Nakamoto. ((("satoshi")))
|
||||
|
||||
Satoshi Nakamoto::
|
||||
Satoshi Nakamoto is the name used by the person or people who designed Bitcoin and created its original reference implementation, Bitcoin Core. As a part of the implementation, they also devised the first blockchain database. In the process they were the first to solve the double spending problem for digital currency. Their real identity remains unknown.
|
||||
|
||||
|
||||
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=== Code Examples
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((("code examples, obtaining and using", id="codeuse00")))The examples are illustrated in Python, C++, and using the command line of a Unix-like operating system such as Linux or macOS. All code snippets are available in the https://github.com/aantonop/bitcoinbook[GitHub repository] in the _code_ subdirectory of the main repo. Fork the book code, try the code examples, or submit corrections via GitHub.
|
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((("code examples, obtaining and using", id="codeuse00")))The examples are illustrated in Python, C++, and using the command line of a Unix-like operating system such as Linux or macOS. All code snippets are available in the https://github.com/bitcoinbook/bitcoinbook[GitHub repository] in the _code_ subdirectory of the main repo. Fork the book code, try the code examples, or submit corrections via GitHub.
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|
||||
All the code snippets can be replicated on most operating systems with a minimal installation of compilers and interpreters for the corresponding languages. Where necessary, we provide basic installation instructions and step-by-step examples of the output of those instructions.
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Loading…
Reference in New Issue
Block a user