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[[ch9]]
== Alternative chains, currencies and applications
Bitcoin was neither the beginning nor the end of the digital currency evolution. It came from twenty years of research in distributed systems and currencies and brought a revolutionary new technology into the space: the de-centralized consensus mechanism based on Proof-of-Work. The invention at the heart of bitcoin has ushered a wave of innovation in currencies, financial services, economics, distributed systems, voting systems, corporate governance and contracts.
Bitcoin was neither the beginning nor the end of the digital currency evolution. It came from twenty years of research in distributed systems and currencies and brought a revolutionary new technology into the space: the de-centralized consensus mechanism based on Proof-of-Work. The invention at the heart of bitcoin has ushered a wave of innovation in currencies, financial services, economics, distributed systems, voting systems, corporate governance, and contracts.
In this chapter we'll examine the many offshoots of the bitcoin and blockchain inventions, the alternative chains, currencies and applications built since the introduction of this technology in 2009.
@ -15,7 +15,7 @@ Bitcoin is an open source project and its code has been used as the basis for ma
There are a number of protocol layers implemented on top of bitcoin's blockchain. These _meta-coins_, _meta-chains_, or _blockchain apps_ use the blockchain as an application platform or extend the bitcoin protocol by adding protocol layers. Examples include Colored Coins, Mastercoin and Counterparty.
In the next section we will examine a few notable alt-coins, such as Litecoin, Dogecoin, Freicoin, Primecoin, Peercoin, Darkcoin and Zerocoin. These alt-coins are notable for historical reasons or because they are good examples a specific type of alt-coin innovation, not because they are the most valuable or "best" alt-coins.
In the next section we will examine a few notable alt-coins, such as Litecoin, Dogecoin, Freicoin, Primecoin, Peercoin, Darkcoin, and Zerocoin. These alt-coins are notable for historical reasons or because they are good examples for a specific type of alt-coin innovation, not because they are the most valuable or "best" alt-coins.
In addition to the alt-coins, there are also a number of alternative blockchain implementations that are not really "coins", which I call _alt-chains_. These alt-chains implement a consensus algorithm and distributed ledger as a platform for contracts, name registration or other applications. Alt-chains use the same basic building blocks and sometimes also use a currency or token as a payment mechanism, but their primary purpose is not currency. We will look at Namecoin, Ethereum and NXT as examples of alt-chains.
@ -25,7 +25,7 @@ Finally, there are a number of bitcoin contenders that offer digital currency or
=== Meta-Coin Platforms
Meta-coins and meta-chains are software layers implemented on top of bitcoin, either implementing a currency-inside-a-currency, or a platform/protocol overlay inside the bitcoin system. These function layers extend the core bitcoin protocol and add features and capabilities by encoding additional data inside bitcoin transactions and bitcoin addresses. The first implementations of meta-coins used various "hacks" to add meta-data to the bitcoin blockchain, such as using bitcoin addresses to encode data or using unused transaction fields (eg. the transaction sequence field) to encode meta-data about the added protocol layer. Since the introduction of the OP_RETURN transaction scripting opcode, the meta-coins have been able to record meta-data more directly in the blockchain and most are migrating to using that instead.
Meta-coins and meta-chains are software layers implemented on top of bitcoin, either implementing a currency-inside-a-currency, or a platform/protocol overlay inside the bitcoin system. These function layers extend the core bitcoin protocol and add features and capabilities by encoding additional data inside bitcoin transactions and bitcoin addresses. The first implementations of meta-coins used various "hacks" to add meta-data to the bitcoin blockchain, such as using bitcoin addresses to encode data or using unused transaction fields (e.g. the transaction sequence field) to encode meta-data about the added protocol layer. Since the introduction of the OP_RETURN transaction scripting opcode, the meta-coins have been able to record meta-data more directly in the blockchain and most are migrating to using that instead.
==== Colored Coins
@ -61,7 +61,7 @@ To demonstrate the use of colored coins, we have created a set of 20 colored coi
==== Mastercoin
Mastercoin is a protocol layer on top of bitcoin that supports a platform for various applications extending the bitcoin system. Mastercoin uses the currency MST as a token for conducting Mastercoin transactions but it not primarily a currency. Rather it is a platform for building other things, such as user currencies, smart property tokens, de-centralized asset exchanges, contracts etc. Think of Mastercoin as an application-layer protocol on top of bitcoin's financial transaction transport-layer, just like HTTP runs on top of TCP.
Mastercoin is a protocol layer on top of bitcoin that supports a platform for various applications extending the bitcoin system. Mastercoin uses the currency MST as a token for conducting Mastercoin transactions but it is not primarily a currency. Rather it is a platform for building other things, such as user currencies, smart property tokens, de-centralized asset exchanges, contracts etc. Think of Mastercoin as an application-layer protocol on top of bitcoin's financial transaction transport-layer, just like HTTP runs on top of TCP.
Mastercoin operates primarily through transactions sent to and from a special bitcoin address called the "exodus" address (+1EXoDusjGwvnjZUyKkxZ4UHEf77z6A5S4P+), just like HTTP uses a specific TCP port (port 80) to differentiate its traffic from the rest of the TCP traffic. The Mastercoin protocol is gradually transitioning from using the specialized exodus address and multi-signatures to using the OP_RETURN bitcoin operator to encode transaction metadata.
@ -71,7 +71,7 @@ Counterparty is another protocol layer implemented on top of bitcoin. Counterpar
=== Alt-coins
Alt-coins are digital currencies implemented using the same design pattern as bitcoin, with a completely separate blockchain and network. The vast majority of alt-coins are derived from bitcoin's source code, also known as "forks". Some are implemented "from scratch" based on the blockchain model but without using any of bitcoin's source code. Alt-coins and alt-chains (in the next section) are both separate implementations of blockchain technology and both forms use their own blockchain. The difference in the terms is to indicate that alt-coins are primarily used as currency, whereas alt-chains are used for other purposes, not primarily currency.
Alt-coins are digital currencies implemented using the same design pattern as bitcoin, but with a completely separate blockchain and network. The vast majority of alt-coins are derived from bitcoin's source code, also known as "forks". Some are implemented "from scratch" based on the blockchain model but without using any of bitcoin's source code. Alt-coins and alt-chains (in the next section) are both separate implementations of blockchain technology and both forms use their own blockchain. The difference in the terms is to indicate that alt-coins are primarily used as currency, whereas alt-chains are used for other purposes, not primarily currency.
The first alt-coins appeared in August of 2011 as forks of the bitcoin source code. Strictly speaking, the first major fork of bitcoin's code was not an alt-coin but the alt-chain _Namecoin_, which will be discussed in the next section.
@ -79,9 +79,9 @@ Based on the date of announcement, the first alt-coin appears to be _IXCoin_, la
In September of 2011, _Tenebrix_ was launched. Tenebrix was the first crypto-currency to implement an alternative Proof-of-Work algorithm, namely _scrypt_, an algorithm originally designed for password stretching (brute-force resistance). The stated goal of Tenebrix was to make a coin that was resistant to mining with GPUs and ASICs, by using a memory-intensive algorithm. Tenebrix did not succeed as a currency, but it was the basis for Litecoin, which has enjoyed great success and has spawned hundreds of clones.
_Litecoin_, in addition to using scrypt as the Proof-of-Work algorithm, also implemented a faster block generation time, targeted at 2.5 minutes instead of bitcoin's 10 minutes. The resulting currency is touted as "silver to bitcoin's gold" and intended as a light-weight alternative currency. Due to the faster confirmation time and 84 million total currency limit, many adherents of Litecoin believe it is better suited for retail transactions than bitcoin.
_Litecoin_, in addition to using scrypt as the Proof-of-Work algorithm, also implemented a faster block generation time, targeted at 2.5 minutes instead of bitcoin's 10 minutes. The resulting currency is touted as "silver to bitcoin's gold" and is intended as a light-weight alternative currency. Due to the faster confirmation time and the 84 million total currency limit, many adherents of Litecoin believe it is better suited for retail transactions than bitcoin.
Alt-coins continued to proliferate in 2011 and 2012, either based on bitcoin, or on Litecoin. In the beginning of 2013 there were 20 alt-coins vying for position in the market. By the end of 2013 however, this number had exploded to 200, with 2013 quickly becoming the "year of the alt-coins". The growth of alt-coins continued in 2014 with more than 500 alt-coins now in existence. More than half the alt-coins today are clones of Litecoin.
Alt-coins continued to proliferate in 2011 and 2012, either based on bitcoin or on Litecoin. In the beginning of 2013 there were 20 alt-coins vying for position in the market. By the end of 2013 however, this number had exploded to 200, with 2013 quickly becoming the "year of the alt-coins". The growth of alt-coins continued in 2014 with more than 500 alt-coins now in existence. More than half the alt-coins today are clones of Litecoin.
Creating an alt-coin is easy, which is why there are now more than 500 of them. Most of the alt-coins differ very slightly from bitcoin and do not offer anything worth studying. Many are in fact just attempts to enrich their creators. Among the copycats and pump-and-dump schemes, there are however some notable exceptions and very important innovations. These alt-coins take radically different approaches or add significant innovation to bitcoin's design pattern. There are three primary areas where alt-coins differentiate from bitcoin:
@ -89,7 +89,7 @@ Creating an alt-coin is easy, which is why there are now more than 500 of them.
* Different Proof-of-Work or consensus mechanism
* Specific features, such as strong anonymity
A graphical timeline of alt-coins and alt-chains can be found at http://mapofcoins.com
A graphical timeline of alt-coins and alt-chains can be found at http://mapofcoins.com.
==== Evaluating an alt-coin
@ -101,7 +101,7 @@ Here are some questions to ask about how well an alt-coin differentiates from bi
* Does the alt-coin differentiate sufficiently from bitcoin?
* Is the difference compelling enough to attract users away from bitcoin?
* Does the alt-coin address an interesting niche market or application?
* Can the alt-coin attract enough miners to be secure against consensus attacks?
* Can the alt-coin attract enough miners to be secured against consensus attacks?
Here are some of the key financial and market metrics to examine:
@ -146,7 +146,7 @@ Freicoin was introduced in July 2012. It is a _demurrage currency_, meaning that
==== Consensus Innovation: Peercoin, Myriad, Blackcoin, Vericoin, NXT
Bitcoin's consensus mechanism is based on Proof-of-Work using the SHA256 algorithm. The first alt-coins introduced scrypt as an alternative Proof-of-Work algorithms, as a way to make mining more CPU-friendly and less susceptible to centralization with ASICs. Since then, innovation in the consensus mechanism has continued at a frenetic pace. Several alt-coins adopted a variety of algorithms such as scrypt, scrypt-N, Skein, Groestl, SHA3, X11, Blake and others. Some alt-coins combined multiple algorithms for Proof-of-Work. In 2013 we saw the invention of an alternative to Proof-of-Work, called _Proof-of-Stake_, which forms the basis of many modern alt-coins.
Bitcoin's consensus mechanism is based on Proof-of-Work using the SHA256 algorithm. The first alt-coins introduced scrypt as an alternative Proof-of-Work algorithms, as a way to make mining more CPU-friendly and less susceptible to centralization with ASICs. Since then, innovation in the consensus mechanism has continued at a frenetic pace. Several alt-coins adopted a variety of algorithms such as scrypt, scrypt-N, Skein, Groestl, SHA3, X11, Blake, and others. Some alt-coins combined multiple algorithms for Proof-of-Work. In 2013 we saw the invention of an alternative to Proof-of-Work, called _Proof-of-Stake_, which forms the basis of many modern alt-coins.
Proof-of-Stake is a system by which existing owners of a currency can "stake" currency as interest-bearing collateral. Somewhat like a Certificate of Deposit (CD), participants can reserve a portion of their currency holdings, while earning an investment return in the form of new currency (issued as interest payments) and transaction fees.
@ -198,11 +198,11 @@ NXT (pronounced "Next") is a "pure" Proof-of-Stake alt-coin, in that it does not
==== Dual-Purpose Mining Innovation: Primecoin, Curecoin, Gridcoin
Bitcoin's Proof-of-Work algorithm has only one purpose: securing the bitcoin network. Compared to traditional payment system security, the cost of mining is not very high. However, it has been criticized by many as "wasteful". The next set of alt-coins attempt to address this concern. Dual-purpose Proof-of-Work algorithms solve a specific "useful" problem, while producing Proof-of-Work to secure the network. The risk of adding an external use to the currency's security is that it also adds external influence to the supply/demand curve.
Bitcoin's Proof-of-Work algorithm has only one purpose: securing the bitcoin network. Compared to traditional payment system security, the cost of mining is not very high. However, it has been criticized by many as being “wasteful". The next set of alt-coins attempt to address this concern. Dual-purpose Proof-of-Work algorithms solve a specific "useful" problem, while producing Proof-of-Work to secure the network. The risk of adding an external use to the currency's security is that it also adds external influence to the supply/demand curve.
*Primecoin*
Primecoin was announced in July 2013. It's Proof-of-Work algorithm searches for prime numbers, computing Cunningham and bi-twin prime chains. Prime numbers are useful in a variety of scientific disciplines. The Primecoin blockchain contains the discovered prime numbers, thereby producing a public record of scientific discovery in parallel to the public ledger of transactions.
Primecoin was announced in July 2013. Its Proof-of-Work algorithm searches for prime numbers, computing Cunningham and bi-twin prime chains. Prime numbers are useful in a variety of scientific disciplines. The Primecoin blockchain contains the discovered prime numbers, thereby producing a public record of scientific discovery in parallel to the public ledger of transactions.
* Block generation: 1 minute
* Total currency: No limit
@ -233,7 +233,7 @@ Bitcoin is often mistakenly characterized as "anonymous" currency. In fact, it i
*Zerocoin/Zerocash*
Zerocoin is a theoretical approach to digital currency anonymity introduced in 2013 by researchers at Johns Hopkins. Zerocash is an alt-coin implementation of Zercoin that is in development and not yet released.
Zerocoin is a theoretical approach to digital currency anonymity introduced in 2013 by researchers at Johns Hopkins. Zerocash is an alt-coin implementation of Zerocoin that is in development and not yet released.
*CryptoNote*
@ -272,7 +272,7 @@ Alt-chains are alternative implementations of the blockchain design pattern, whi
==== Namecoin
Namecoin was the first "fork" of the bitcoin code. Namecoin is a de-centralized key-value registration and transfer platform using a blockchain. It supports a global domain name registry similar to the domain-name registration system on the Internet. Namecoin is currently used as an alternative Domain Name Service (DNS) for the root-level domain +.bit+. Namecoin can also be used to register names and key-value pairs in other namespaces, for storing things like email addresses, encryption keys, SSL certificates, file signatures, voting systems, stock certificates and a myriad other applications.
Namecoin was the first "fork" of the bitcoin code. Namecoin is a de-centralized key-value registration and transfer platform using a blockchain. It supports a global domain name registry similar to the domain-name registration system on the Internet. Namecoin is currently used as an alternative Domain Name Service (DNS) for the root-level domain +.bit+. Namecoin can also be used to register names and key-value pairs in other namespaces, for storing things like email addresses, encryption keys, SSL certificates, file signatures, voting systems, stock certificates and a myriad of other applications.
The Namecoin system includes the namecoin currency (symbol NMC), which is used to pay transaction fees for registration and transfer of names. At current prices, the fee to register a name is 0.01 NMC or approximately 1 US cent. As in bitcoin, the fees are collected by Namecoin miners.
@ -287,7 +287,7 @@ Namecoin's namespaces are not restricted, and anyone can use any namespace in an
* +d/+ is the domain-name namespace for +.bit+ domains
* +id/+ is the namespace for storing person identifiers such as email addresses, PGP keys etc.
* +u/+ is an additional, more structured specfication to store identities (based on openspecs).
* +u/+ is an additional, more structured specification to store identities (based on openspecs).
The Namecoin client is very similar to Bitcoin Core, as it is derived from the same source code. Upon installation, the client will download a full copy of the namecoin blockchain and then will be ready to query and register names. There are three main commands:
@ -355,7 +355,7 @@ else:
=== Future of Currencies
The future of cryptographic currencies overall is even brighter than the future of bitcoin. Bitcoin introduced a completely new form of de-centralized organization and consensus that has spawned hundreds of incredible innovations. These inventions will likely affect broad sectors of the economy, from distributed systems science, to finance, economics, currencies, central banking and corporate governance. Many human activities that previously required centralized institutions or organizations to function as authoritative or trusted points of control can now be de-centralized. The invention of the blockchain and consensus system will significantly reduce the cost of organization and coordination on large scale systems, while removing opportunities for concentration of power, corruption and regulatory capture.
The future of cryptographic currencies overall is even brighter than the future of bitcoin. Bitcoin introduced a completely new form of de-centralized organization and consensus that has spawned hundreds of incredible innovations. These inventions will likely affect broad sectors of the economy, from distributed systems science, to finance, economics, currencies, central banking, and corporate governance. Many human activities that previously required centralized institutions or organizations to function as authoritative or trusted points of control can now be de-centralized. The invention of the blockchain and consensus system will significantly reduce the cost of organization and coordination on large scale systems, while removing opportunities for concentration of power, corruption and regulatory capture.