AU QC1 edits

appdx-scriptops.asciidoc

@@ -2,9 +2,12 @@
 [appendix]
 == Transaction Script Language Operators, Constants, and Symbols
 
-<<tx_script_ops_table_pushdata>> shows operators for pushing values onto the stack.((("transactions", "scripts and Script language", id="TRlang14")))((("scripting", "Script language operators, constants, and symbols", id="SCRlang14")))
+[NOTE]
+====
+Tables and descriptions sourced from https://en.bitcoin.it/wiki/Script[].
+====
 
-_Tables and descriptions sourced from https://en.bitcoin.it/wiki/Script[]_.
+<<tx_script_ops_table_pushdata>> shows operators for pushing values onto the stack.((("transactions", "scripts and Script language", id="TRlang14")))((("scripting", "Script language operators, constants, and symbols", id="SCRlang14")))
 
 [[tx_script_ops_table_pushdata]]
 .Push value onto stack

appdx-segwit.asciidoc

@@ -2,7 +2,7 @@
 [appendix]
 == Segregated Witness
 
-((("segwit (Segregated Witness)", id="segwit16")))Segregated Witness (segwit) is an upgrade to the bitcoin consensus rules and network protocol, scheduled for implementation in the second half of 2016.
+((("segwit (Segregated Witness)", id="segwit16")))Segregated Witness (segwit) is an upgrade to the bitcoin consensus rules and network protocol, proposed and implemented as a BIP-9 soft-fork that is currently (mid-2017) pending activation. 
 
 In cryptography, the term "witness" is used to describe a solution to a cryptographic puzzle. In bitcoin terms, the witness satisfies a cryptographic condition placed on a unspent transaction output (UTXO).
 
@@ -29,7 +29,7 @@ https://github.com/bitcoin/bips/blob/master/bip-0145.mediawiki[BIP-145] :: getbl
 
 Segregated Witness is an architectural change that has several effects on the scalability, security, economic incentives, and performance of bitcoin:
 
-Transaction Malleability :: By moving the witness outside the transaction, the transaction hash used as an identifier no longer includes the witness data. Since the witness data is the only part of the transaction that can be modified by a third party (see <<transaction malleability>> and <<segwit_txid>>), removing it also removes the opportunity for transaction malleability attacks. With Segregated Witness, transaction hashes become immutable by anyone other than the creator of the transaction, which greatly improves the implementation of many other protocols that rely on advanced bitcoin transaction construction, such as payment channels, chained transactions, and lightning networks.
+Transaction Malleability :: By moving the witness outside the transaction, the transaction hash used as an identifier no longer includes the witness data. Since the witness data is the only part of the transaction that can be modified by a third party (see <<segwit_txid>>), removing it also removes the opportunity for transaction malleability attacks. With Segregated Witness, transaction hashes become immutable by anyone other than the creator of the transaction, which greatly improves the implementation of many other protocols that rely on advanced bitcoin transaction construction, such as payment channels, chained transactions, and lightning networks.
 
 Script Versioning :: With the introduction of Segregated Witness scripts, every locking script is preceded by a _script version_ number, similar to how transactions and blocks have version numbers. The addition of a script version number allows the scripting language to be upgraded in a backward-compatible way (i.e., using soft fork upgrades) to introduce new script operands, syntax, or semantics. The ability to upgrade the scripting language in a nondisruptive way will greatly accelerate the rate of innovation in bitcoin.
 

ch01.asciidoc

@@ -45,9 +45,9 @@ When cryptography started becoming more broadly available and understood in the
 
 === History of Bitcoin
 
-((("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. 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.
+((("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.
 
-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 is estimated at between $10 billion and $15 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.
+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.
 
 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.
 
@@ -116,13 +116,13 @@ Third-party API client:: ((("third-party API clients")))A third-party API client
 
 Combining these categorizations, many bitcoin wallets fall into a few groups, with the three most common being desktop full client, mobile lightweight wallet, and web third-party wallet. The lines between different categories are often blurry, as many wallets run on multiple platforms and can interact with the network in different ways.
 
-For the purposes of this book, we will be demonstrating the use of a variety of downloadable bitcoin clients, from the reference implementation (Bitcoin Core) to mobile and web wallets. Some of the examples will require the use of Bitcoin Core, which, in addition to being a full client, also exposes APIs to the wallet, network, and transaction services. If you are planning to explore the programmatic interfaces into the bitcoin system, you will need to run Bitcoin Core.((("", startref="GSwallet01")))((("", startref="Wselect01")))
+For the purposes of this book, we will be demonstrating the use of a variety of downloadable bitcoin clients, from the reference implementation (Bitcoin Core) to mobile and web wallets. Some of the examples will require the use of Bitcoin Core, which, in addition to being a full client, also exposes APIs to the wallet, network, and transaction services. If you are planning to explore the programmatic interfaces into the bitcoin system, you will need to run Bitcoin Core, or one of the alternative clients (see <<alt_libraries>>).((("", startref="GSwallet01")))((("", startref="Wselect01")))
 
 ==== Quick Start
 
 ((("getting started", "quick start example", id="GSquick01")))((("wallets", "quick start example", id="Wquick01")))Alice, who we introduced in <<user-stories>>, is not a technical user and only recently heard about bitcoin from her friend Joe. While at a party, Joe is once again enthusiastically explaining bitcoin to all around him and is offering a demonstration. Intrigued, Alice asks how she can get started with bitcoin. Joe says that a mobile wallet is best for new users and he recommends a few of his favorite wallets. Alice downloads "Mycelium" for Android and installs it on her phone.
 
-When Alice runs Mycelium for the first time, as with many bitcoin wallets, the application automatically creates a new wallet for her. Alice sees the wallet on her screen, as shown in <<mycelium-welcome>>.
+When Alice runs Mycelium for the first time, as with many bitcoin wallets, the application automatically creates a new wallet for her. Alice sees the wallet on her screen, as shown in <<mycelium-welcome>> (note: Do _not_ send bitcoin to this sample address, it will be lost forever).
 
 [[mycelium-welcome]]
 .The Mycelium Mobile Wallet
@@ -171,8 +171,8 @@ Alice was introduced to bitcoin by a friend so she has an easy way to acquire he
 There are hundreds of applications and websites that can provide the current market rate. Here are some of the most popular:
 
 http://bitcoinaverage.com/[Bitcoin Average]:: ((("BitcoinAverage")))A site that provides a simple view of the volume-weighted-average for each currency.
-http://bitcoincharts.com[Bitcoin Charts]:: ((("Bitcoin Charts")))A market data listing service that shows the market rate of bitcoin across many exchanges around the globe, denominated in different local currencies.
-http://www.zeroblock.com/[ZeroBlock]:: ((("ZeroBlock")))A free Android and iOS application that can display a bitcoin price from different exchanges.
+http://coincap.io/[CoinCap]:: A service listing the market capitalization and exchange rates of hundreds of crypto-currencies, including bitcoin.
+http://www.cmegroup.com/trading/cf-bitcoin-reference-rate.html[Chicago Mercantile Exchange Bitcoin Reference Rate]:: A reference rate that can be used for institutional and contractual reference, provided as part of investment data feeds by the CME.
 
 In addition to these various sites and applications, most bitcoin wallets will automatically convert amounts between bitcoin and other currencies. Joe will use his wallet to convert the price automatically before sending bitcoin to Alice.
 

ch02.asciidoc

@@ -284,4 +284,4 @@ As Bob spends the payments received from Alice and other customers, he extends t
 .Alice's transaction as part of a transaction chain from Joe to Gopesh
 image::images/mbc2_0210.png["Alice's transaction as part of a transaction chain"]
 
-In this chapter, we saw how transactions build a chain that moves value from owner to owner. We also tracked Alice's transaction, from the moment it was created in her wallet, through the bitcoin network and to the miners who recorded it on the blockchain. In the next few chapters we will examine the specific technologies behind wallets, addresses, signatures, transactions, the network, and finally mining.((("", startref="BCover02")))((("", startref="DCSover02"))) 
+In this chapter, we saw how transactions build a chain that moves value from owner to owner. We also tracked Alice's transaction, from the moment it was created in her wallet, through the bitcoin network and to the miners who recorded it on the blockchain. In the rest of this book we will examine the specific technologies behind wallets, addresses, signatures, transactions, the network, and finally mining.((("", startref="BCover02")))((("", startref="DCSover02"))) 

ch04.asciidoc

@@ -7,7 +7,7 @@
 
 ((("digital keys", see="keys and addresses")))((("keys and addresses", "overview of", id="KAover04")))((("digital signatures", "purpose of")))Ownership of bitcoin is established through _digital keys_, _bitcoin addresses_, and _digital signatures_. The digital keys are not actually stored in the network, but are instead created and stored by users in a file, or simple database, called a _wallet_. The digital keys in a user's wallet are completely independent of the bitcoin protocol and can be generated and managed by the user's wallet software without reference to the blockchain or access to the internet. Keys enable many of the interesting properties of bitcoin, including decentralized trust and control, ownership attestation, and the cryptographic-proof security model. 
 
-Every bitcoin transaction requires a valid digital signature to be included in the blockchain, which can only be generated with a secret key; therefore, anyone with a copy of that key has control of the bitcoin in that account. ((("witnesses")))The digital signature used to spend funds is also referred to as a _witness_, a term used in cryptography. The witness data in a bitcoin transaction testifies to the true ownership of the funds being spent.
+Most bitcoin transactions requires a valid digital signature to be included in the blockchain, which can only be generated with a secret key; therefore, anyone with a copy of that key has control of the bitcoin. ((("witnesses")))The digital signature used to spend funds is also referred to as a _witness_, a term used in cryptography. The witness data in a bitcoin transaction testifies to the true ownership of the funds being spent.
 
 ((("public and private keys", "key pairs")))((("public and private keys", see="also keys and addresses")))Keys come in pairs consisting of a private (secret) key and a public key. Think of the public key as similar to a bank account number and the private key as similar to the secret PIN, or signature on a check, that provides control over the account. These digital keys are very rarely seen by the users of bitcoin. For the most part, they are stored inside the wallet file and managed by the bitcoin wallet software. 
 
@@ -58,16 +58,16 @@ The bitcoin private key is just a number. You can pick your private keys randoml
 
 ===== Generating a private key from a random number
 
-The first and most important step in generating keys is to find a secure source of entropy, or randomness. Creating a bitcoin key is essentially the same as "Pick a number between 1 and 2^256^." The exact method you use to pick that number does not matter as long as it is not predictable or repeatable. Bitcoin software uses the underlying operating system's random number generators to produce 256 bits of entropy (randomness). Usually, the OS random number generator is initialized by a human source of randomness, which is why you may be asked to wiggle your mouse around for a few seconds. For the truly paranoid, nothing beats dice, pencil, and paper.
+The first and most important step in generating keys is to find a secure source of entropy, or randomness. Creating a bitcoin key is essentially the same as "Pick a number between 1 and 2^256^." The exact method you use to pick that number does not matter as long as it is not predictable or repeatable. Bitcoin software uses the underlying operating system's random number generators to produce 256 bits of entropy (randomness). Usually, the OS random number generator is initialized by a human source of randomness, which is why you may be asked to wiggle your mouse around for a few seconds.
 
-More accurately, the private key can be any number between +1+ and +n - 1+, where n is a constant (n = 1.158 * 10^77^, slightly less than 2^256^) defined as the order of the elliptic curve used in bitcoin (see <<elliptic_curve>>). To create such a key, we randomly pick a 256-bit number and check that it is less than +n - 1+. In programming terms, this is usually achieved by feeding a larger string of random bits, collected from a cryptographically secure source of randomness, into the SHA256 hash algorithm, which will conveniently produce a 256-bit number. If the result is less than +n - 1+, we have a suitable private key. Otherwise, we simply try again with another random number. 
+More precisely, the private key can be any number between +1+ and +n - 1+, where n is a constant (n = 1.158 * 10^77^, slightly less than 2^256^) defined as the order of the elliptic curve used in bitcoin (see <<elliptic_curve>>). To create such a key, we randomly pick a 256-bit number and check that it is less than +n - 1+. In programming terms, this is usually achieved by feeding a larger string of random bits, collected from a cryptographically secure source of randomness, into the SHA256 hash algorithm, which will conveniently produce a 256-bit number. If the result is less than +n - 1+, we have a suitable private key. Otherwise, we simply try again with another random number. 
 
-[TIP]
+[WARNING]
 ====
 ((("warnings and cautions", "random number generation")))Do not write your own code to create a random number or use a "simple" random number generator offered by your programming language. Use a cryptographically secure pseudorandom number generator (CSPRNG) with a seed from a source of sufficient entropy. Study the documentation of the random number generator library you choose to make sure it is cryptographically secure. Correct implementation of the CSPRNG is critical to the security of the keys.
 ====
 
-The following is a randomly generated private key (k) shown in hexadecimal format (256 binary digits shown as 64 hexadecimal digits, each 4 bits):
+The following is a randomly generated private key (k) shown in hexadecimal format (256 bits shown as 64 hexadecimal digits, each 4 bits):
 
 ----
 1E99423A4ED27608A15A2616A2B0E9E52CED330AC530EDCC32C8FFC6A526AEDD