((("pycoin library")))The Python library http://github.com/richardkiss/pycoin[+pycoin+], originally written and maintained by Richard Kiss, is a Python-based library that supports manipulation of bitcoin keys and transactions, even supporting the scripting language enough to properly deal with nonstandard transactions.
((("pycoin library")))The Python library https://github.com/richardkiss/pycoin[+pycoin+], originally written and maintained by Richard Kiss, is a Python-based library that supports manipulation of bitcoin keys and transactions, even supporting the scripting language enough to properly deal with nonstandard transactions.
The pycoin library supports both Python 2 (2.7.x) and Python 3 (3.3 and later) and comes with some handy command-line utilities, +ku+ and +tx+.
@ -698,7 +698,7 @@ Let's look at the pattern "1Kids" as a number and see how frequently we might fi
As you can see, Eugenia won't be creating the vanity address "1KidsCharity" anytime soon, even if she had access to several thousand computers. Each additional character increases the difficulty by a factor of 58. Patterns with more than seven characters are usually found by specialized hardware, such as custom-built desktops with multiple GPUs. These are often repurposed bitcoin mining "rigs" that are no longer profitable for bitcoin mining but can be used to find vanity addresses. Vanity searches on GPU systems are many orders of magnitude faster than on a general-purpose CPU.
Another way to find a vanity address is to outsource the work to a pool of vanity miners, such as the pool at http://vanitypool.appspot.com[Vanity Pool]. A pool of this type is a service that allows those with GPU hardware to earn bitcoin searching for vanity addresses for others. For a small payment (0.01 bitcoin or approximately $5 at the time of this writing), Eugenia can outsource the search for a seven-character pattern vanity address and get results in a few hours instead of having to run a CPU search for months.
Another way to find a vanity address is to outsource the work to a pool of vanity miners, such as the pool at https://vanitypool.appspot.com[Vanity Pool]. A pool of this type is a service that allows those with GPU hardware to earn bitcoin searching for vanity addresses for others. For a small payment (0.01 bitcoin or approximately $5 at the time of this writing), Eugenia can outsource the search for a seven-character pattern vanity address and get results in a few hours instead of having to run a CPU search for months.
Generating a vanity address is a brute-force exercise: try a random key, check the resulting address to see if it matches the desired pattern, repeat until successful. <<vanity_miner_code>> shows an example of a "vanity miner," a program designed to find vanity addresses, written in C++. The example uses the libbitcoin library, which we introduced in <<alt_libraries>>.
@ -696,7 +696,7 @@ Note that in verifying the signature, the private key is neither known nor revea
[TIP]
====
ECDSA is necessarily a fairly complicated piece of math; a full explanation is beyond the scope of this book. A number of great guides online take you through it step by step: search for "ECDSA explained" or try this one: http://bit.ly/2r0HhGB[].
ECDSA is necessarily a fairly complicated piece of math; a full explanation is beyond the scope of this book. A number of great guides online take you through it step by step: search for "ECDSA explained" or try this one: https://bit.ly/2r0HhGB[].
@ -244,7 +244,7 @@ In version 0.9 of the Bitcoin Core client, a compromise was reached with the int
RETURN <data>
----
((("Proof of Existence")))((("DOCPROOF prefix")))The data portion is limited to 80 bytes and most often represents a hash, such as the output from the SHA256 algorithm (32 bytes). Many applications put a prefix in front of the data to help identify the application. For example, the http://proofofexistence.com[Proof of Existence] digital notarization service uses the 8-byte prefix +DOCPROOF+, which is ASCII encoded as +44 4f 43 50 52 4f 4f 46+ in hexadecimal.
((("Proof of Existence")))((("DOCPROOF prefix")))The data portion is limited to 80 bytes and most often represents a hash, such as the output from the SHA256 algorithm (32 bytes). Many applications put a prefix in front of the data to help identify the application. For example, the https://proofofexistence.com[Proof of Existence] digital notarization service uses the 8-byte prefix +DOCPROOF+, which is ASCII encoded as +44 4f 43 50 52 4f 4f 46+ in hexadecimal.
Keep in mind that there is no "unlocking script" that corresponds to +RETURN+ that could possibly be used to "spend" a +RETURN+ output. The whole point of +RETURN+ is that you can't spend the money locked in that output, and therefore it does not need to be held in the UTXO set as potentially spendable—+RETURN+ is _provably unspendable_. +RETURN+ is usually an output with a zero bitcoin amount, because any bitcoin assigned to such an output is effectively lost forever. If a +RETURN+ is referenced as an input in a transaction, the script validation engine will halt the execution of the validation script and mark the transaction as invalid. The execution of +RETURN+ essentially causes the script to "RETURN" with a +FALSE+ and halt. Thus, if you accidentally reference a +RETURN+ output as an input in a transaction, that transaction is invalid.
((("propagation", "relay networks and")))Bitcoin miners are engaged in a time-sensitive competition to solve the Proof-of-Work problem and extend the blockchain (see <<mining>>). While participating in this competition, bitcoin miners must minimize the time between the propagation of a winning block and the beginning of the next round of competition. In mining, network latency is directly related to profit margins.
A _Bitcoin Relay Network_ is a network that attempts to minimize the latency in the transmission of blocks between miners. The original http://www.bitcoinrelaynetwork.org[Bitcoin Relay Network] was created by core developer Matt Corallo in 2015 to enable fast synchronization of blocks between miners with very low latency. The network consisted of several specialized nodes hosted on the Amazon Web Services infrastructure around the world and served to connect the majority of miners and mining pools.
A _Bitcoin Relay Network_ is a network that attempts to minimize the latency in the transmission of blocks between miners. The original https://www.bitcoinrelaynetwork.org[Bitcoin Relay Network] was created by core developer Matt Corallo in 2015 to enable fast synchronization of blocks between miners with very low latency. The network consisted of several specialized nodes hosted on the Amazon Web Services infrastructure around the world and served to connect the majority of miners and mining pools.
((("Fast Internet Bitcoin Relay Engine (FIBRE)")))((("Compact Block optimization")))The original Bitcoin Relay Network was replaced in 2016 with the introduction of the _Fast Internet Bitcoin Relay Engine_ or http://bitcoinfibre.org[_FIBRE_], also created by core developer Matt Corallo. FIBRE is a UDP-based relay network that relays blocks within a network of nodes. FIBRE implements _compact block_ optimization to further reduce the amount of data transmitted and the network latency.
((("Fast Internet Bitcoin Relay Engine (FIBRE)")))((("Compact Block optimization")))The original Bitcoin Relay Network was replaced in 2016 with the introduction of the _Fast Internet Bitcoin Relay Engine_ or https://bitcoinfibre.org[_FIBRE_], also created by core developer Matt Corallo. FIBRE is a UDP-based relay network that relays blocks within a network of nodes. FIBRE implements _compact block_ optimization to further reduce the amount of data transmitted and the network latency.
((("Falcon Relay Network")))Another relay network (still in the proposal phase) is http://www.falcon-net.org/about[_Falcon_], based on research at Cornell University. Falcon uses "cut-through-routing" instead of "store-and-forward" to reduce latency by propagating parts of blocks as they are received rather than waiting until a complete block is received.
((("Falcon Relay Network")))Another relay network (still in the proposal phase) is https://www.falcon-net.org/about[_Falcon_], based on research at Cornell University. Falcon uses "cut-through-routing" instead of "store-and-forward" to reduce latency by propagating parts of blocks as they are received rather than waiting until a complete block is received.
Relay networks are not replacements for bitcoin's P2P network. Instead they are overlay networks that provide additional connectivity between nodes with specialized needs. Like freeways are not replacements for rural roads, but rather shortcuts between two points with heavy traffic, you still need small roads to connect to the freeways.
@ -74,7 +74,7 @@ To connect to a known peer, nodes establish a TCP connection, usually to port 83
+subver+:: A sub-version showing the type of software running on this node (e.g., pass:[<span class="keep-together"><code>/Satoshi:0.9.2.1/</code></span>])
+BestHeight+:: The block height of this node's blockchain
(See http://bit.ly/1qlsC7w[GitHub] for an example of the +version+ network message.)
(See https://bit.ly/1qlsC7w[GitHub] for an example of the +version+ network message.)
The +version+ message is always the first message sent by any peer to another peer. The local peer receiving a +version+ message will examine the remote peer's reported +nVersion+ and decide if the remote peer is compatible. If the remote peer is compatible, the local peer will acknowledge the +version+ message and establish a connection by sending a +verack+ message.
@ -278,7 +278,7 @@ As the full node sends transactions to the SPV node, the SPV node discards any f
The node setting the bloom filter can interactively add patterns to the filter by sending a +filteradd+ message. To clear the bloom filter, the node can send a +filterclear+ message. Because it is not possible to remove a pattern from a bloom filter, a node has to clear and resend a new bloom filter if a pattern is no longer desired.
The network protocol and bloom filter mechanism for SPV nodes is defined in http://bit.ly/1x6qCiO[BIP-37 (Peer Services)].((("", startref="BNebloom08")))((("", startref="bloom08")))
The network protocol and bloom filter mechanism for SPV nodes is defined in https://bit.ly/1x6qCiO[BIP-37 (Peer Services)].((("", startref="BNebloom08")))((("", startref="bloom08")))
@ -74,7 +74,7 @@ A block's _block hash_ always identifies a single block uniquely. A block also a
Every node always starts with a blockchain of at least one block because the genesis block is statically encoded within the bitcoin client software, such that it cannot be altered. Every node always "knows" the genesis block's hash and structure, the fixed time it was created, and even the single transaction within. Thus, every node has the starting point for the blockchain, a secure "root" from which to build a trusted blockchain.
See the statically encoded genesis block inside the Bitcoin Core client, in http://bit.ly/1x6rcwP[_chainparams.cpp_].
See the statically encoded genesis block inside the Bitcoin Core client, in https://bit.ly/1x6rcwP[_chainparams.cpp_].
The following identifier hash belongs to the genesis block:
@ -358,7 +358,7 @@ Alice has paid Eric 1 bitcoin without opening a channel to Eric. None of the int
((("Lightning Network", "transport and routing")))All communications between LN nodes are encrypted point-to-point. In addition, nodes have a long-term public key that they use as an identifier and to authenticate each other.
Whenever a node wishes to send a payment to another node, it must first construct a _path_ through the network by connecting payment channels with sufficient capacity. Nodes advertise routing information, including what channels they have open, how much capacity each channel has, and what fees they charge to route payments. The routing information can be shared in a variety of ways and different routing protocols are likely to emerge as Lightning Network technology advances. Some Lightning Network implementations use the IRC protocol as a convenient mechanism for nodes to announce routing information. Another implementation of route discovery uses a P2P model where nodes propagate channel announcements to their peers, in a "flooding" model, similar to how bitcoin propagates transactions. Future plans include a proposal called http://bit.ly/2r5TACm[Flare], which is a hybrid routing model with local node "neighborhoods" and longer-range beacon nodes.
Whenever a node wishes to send a payment to another node, it must first construct a _path_ through the network by connecting payment channels with sufficient capacity. Nodes advertise routing information, including what channels they have open, how much capacity each channel has, and what fees they charge to route payments. The routing information can be shared in a variety of ways and different routing protocols are likely to emerge as Lightning Network technology advances. Some Lightning Network implementations use the IRC protocol as a convenient mechanism for nodes to announce routing information. Another implementation of route discovery uses a P2P model where nodes propagate channel announcements to their peers, in a "flooding" model, similar to how bitcoin propagates transactions. Future plans include a proposal called https://bit.ly/2r5TACm[Flare], which is a hybrid routing model with local node "neighborhoods" and longer-range beacon nodes.
In our previous example, Alice's node uses one of these route discovery mechanisms to find one or more paths connecting her node to Eric's node. Once Alice's node has constructed a path, she will initialize that path through the network, by propagating a series of encrypted and nested instructions to connect each of the adjacent payment channels.
@ -85,12 +85,12 @@ DO NOT SEND MONEY TO ANY OF THE ADDRESSES IN THIS BOOK. Your money will be taken
[role = "safarienabled"]
[NOTE]
====
pass:[<a href="http://oreilly.com/safari" class="orm:hideurl"><em class="hyperlink">Safari</em></a>] (formerly Safari Books Online) is a membership-based training and reference platform for enterprise, government, educators, and individuals.
pass:[<a href="https://oreilly.com/safari" class="orm:hideurl"><em class="hyperlink">Safari</em></a>] (formerly Safari Books Online) is a membership-based training and reference platform for enterprise, government, educators, and individuals.
====
Members have access to thousands of books, training videos, Learning Paths, interactive tutorials, and curated playlists from over 250 publishers, including O’Reilly Media, Harvard Business Review, Prentice Hall Professional, Addison-Wesley Professional, Microsoft Press, Sams, Que, Peachpit Press, Adobe, Focal Press, Cisco Press, John Wiley & Sons, Syngress, Morgan Kaufmann, IBM Redbooks, Packt, Adobe Press, FT Press, Apress, Manning, New Riders, McGraw-Hill, Jones & Bartlett, and Course Technology, among others.
For more information, please visit pass:[<a href="http://oreilly.com/safari" class="orm:hideurl"><em>http://oreilly.com/safari</em></a>].
For more information, please visit pass:[<a href="https://oreilly.com/safari" class="orm:hideurl"><em>https://oreilly.com/safari</em></a>].
=== How to Contact Us
@ -109,13 +109,13 @@ For more information, please visit pass:[<a href="http://oreilly.com/safari" cla
To comment or ask technical questions about this book, send email to pass:[<a class="email" href="mailto:bookquestions@oreilly.com"><em>bookquestions@oreilly.com</em></a>].
For more information about our books, courses, conferences, and news, see our website at link:$$http://www.oreilly.com$$[].
For more information about our books, courses, conferences, and news, see our website at link:$$https://www.oreilly.com$$[].
Find us on Facebook: link:$$http://facebook.com/oreilly$$[]
Find us on Facebook: link:$$https://facebook.com/oreilly$$[]
Follow us on Twitter: link:$$http://twitter.com/oreillymedia$$[]
Follow us on Twitter: link:$$https://twitter.com/oreillymedia$$[]
Watch us on YouTube: link:$$http://www.youtube.com/oreillymedia$$[]
Watch us on YouTube: link:$$https://www.youtube.com/oreillymedia$$[]
Dan Raviv
3 years ago