@ -272,24 +272,24 @@ Proof of stake is a system by which existing owners of a currency can "stake" cu
==== Namecoin
((("Namecoin", id="ix_ch09-asciidoc7", range="startofrange")))Namecoin was the first fork of the bitcoin code. Namecoin is a decentralized key-value registration and transfer platform using a block chain. 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)"))) 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.
((("Namecoin", id="ix_ch09-asciidoc7", range="startofrange")))Namecoin was the first fork of the bitcoin code. Namecoin is a decentralized key-value registration and transfer platform using a block chain. 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)"))) domain name service (DNS) for the root-level domain +.bit+. Namecoin also can 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.
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.
Namecoin's basic parameters are the same as bitcoin's:
* Block generation: 10 minutes
* Total currency: 21 million NMC by 2140
* Consensus algorithm: SHA256 Proof-Of-Work
* Market capitalization: $10 million USD in mid-2014
* Consensus algorithm: SHA256 proof of work
* Market capitalization: $10 million in mid-2014
Namecoin's namespaces are not restricted, and anyone can use any namespace in any way. However, certain namespaces have an agreed-upon specification so that when it is read from the blockchain, software knows how to read and proceed from there. If it is malformed, then whatever software you used to read from the specific namespace will throw an error. Some of the popular namespaces are:
Namecoin's namespaces are not restricted, and anyone can use any namespace in any way. However, certain namespaces have an agreed-upon specification so that when it is read from the blockchain, software knows how to read and proceed from there. If it is malformed, then whatever software you used to read from the specific namespace will throw an error. Some of the popular namespaces are:
* +d/+ is the domain-name namespace for +.bit+ domains
* +id/+ is the namespace for storing person identifiers such as email addresses, PGP keys, etc.
* +id/+ is the namespace for storing person identifiers such as email addresses, PGP keys, and so on
* +u/+ is an additional, more structured specification to store identities (based on openspecs)
((("blockchains","namecoin")))The namecoin client is very similar to Bitcoin Core, because 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:((("Namecoin","commands")))
((("blockchains","Namecoin")))The Namecoin client is very similar to Bitcoin Core, because it is derived from the same source code. Upon installation, the client will download a full copy of the Namecoin block chain and then will be ready to query and register names. There are three main commands:((("Namecoin","commands")))
+name_new+:: Query or preregister a name
+name_firstupdate+:: Register a name and make the registration public
The +name_new+ command registers a claim on the name, by creating a hash of the name with a random key. The two strings returned by +name_new+ are the hash and the random key (+a05555e0fc56c023+ in the preceding example) that can be used to make the name registration public. Once that claim has been recorded on the namecoin blockchain it can be converted to a public registration with the +name_firstupdate+ command, by supplying the random key:
The +name_new+ command registers a claim on the name, by creating a hash of the name with a random key. The two strings returned by +name_new+ are the hash and the random key (+a05555e0fc56c023+ in the preceding example) that can be used to make the name registration public. Once that claim has been recorded on the Namecoin block chain it can be converted to a public registration with the +name_firstupdate+ command, by supplying the random key:
Namecoin registrations need to be updated every 36,000 blocks (approximately 200 to 250 days). The +name_update+ command has no fee and therefore renewing domains in Namecoin is free. Third-party providers can handle registration, automatic renewal, and updating via a web interface, for a small fee. With a third-party provider you avoid the need to run a namecoin client, but you lose the independent control of a decentralized name registry offered by Namecoin.(((range="endofrange", startref="ix_ch09-asciidoc7")))
Namecoin registrations need to be updated every 36,000 blocks (approximately 200 to 250 days). The +name_update+ command has no fee and therefore renewing domains in Namecoin is free. Third-party providers can handle registration, automatic renewal, and updating via a web interface, for a small fee. With a third-party provider you avoid the need to run a Namecoin client, but you lose the independent control of a decentralized name registry offered by Namecoin.(((range="endofrange", startref="ix_ch09-asciidoc7")))
==== Bitmessage
((("Bitmessage")))((("messages, sending in blockchain")))Bitmessage is a bitcoin alt-chain that implements a decentralized secure messaging service, essentially a server-less encrypted email system. Bitmessage allows users to compose and send messages to each other, using a bitmessage address. The messages operate in much the same way as a bitcoin transaction, but they are transient—they do not persist beyond two days and if not delivered to the destination node in that time, they are lost. Senders and recipients are pseudonymous—they have no identifiers other than a bitmessage address—but are strongly authenticated, meaning that messages cannot be "spoofed." Bitmessages are encrypted to the recipient and therefore the bitmessage network is resistant to holistic surveillance—an eavesdropper has to compromise the recipient's device in order to intercept messages.
((("Bitmessage")))((("messages, sending in blockchain")))Bitmessage is a bitcoin altchain that implements a decentralized secure messaging service, essentially a server-less encrypted email system. Bitmessage allows users to compose and send messages to each other, using a Bitmessage address. The messages operate in much the same way as a bitcoin transaction, but they are transient—they do not persist beyond two days and if not delivered to the destination node in that time, they are lost. Senders and recipients are pseudonymous—they have no identifiers other than a bitmessage address—but are strongly authenticated, meaning that messages cannot be "spoofed." Bitmessages are encrypted to the recipient and therefore the Bitmessage network is resistant to holistic surveillance—an eavesdropper has to compromise the recipient's device in order to intercept messages.
==== Ethereum
((("contracts, in Ethereum")))((("ether alt-currency")))((("Ethereum")))Ethereum is a Turing-complete contract processing and execution platform based on a blockchain ledger. It is not a clone of bitcoin, but a completely independent design and implementation. Ethereum has a built-in currency, called _ether_, which is required in order to pay for contract execution. Ethereum's blockchain records _contracts_, which are expressed in a low-level, byte-code like, Turing-complete language. Essentially, a contract is a program that runs on every node in the Ethereum system. Ethereum contracts can store data, send and receive ether payments, store ether, and execute an infinite range (hence Turing-complete) of computable actions, acting as decentralized autonomous software agents.
((("contracts, in Ethereum")))((("ether altcurrency")))((("Ethereum")))Ethereum is a Turing-complete contract processing and execution platform based on a block chain ledger. It is not a clone of Bitcoin, but a completely independent design and implementation. Ethereum has a built-in currency, called _ether_, which is required in order to pay for contract execution. Ethereum's blockchain records _contracts_, which are expressed in a low-level, byte code–like, Turing-complete language. Essentially, a contract is a program that runs on every node in the Ethereum system. Ethereum contracts can store data, send and receive ether payments, store ether, and execute an infinite range (hence Turing-complete) of computable actions, acting as decentralized autonomous software agents.
Ethereum can implement quite complex systems that are otherwise implemented as alt-chains themselves. For example, the following is a namecoin-like name registration contract written in Ethereum (or more accurately, written in a high-level language that can be compiled to Ethereum code): (((range="endofrange", startref="ix_ch09-asciidoc6")))(((range="endofrange", startref="ix_ch09-asciidoc5")))
Ethereum can implement quite complex systems that are otherwise implemented as alt chains themselves. For example, the following is a Namecoin-like name registration contract written in Ethereum (or more accurately, written in a high-level language that can be compiled to Ethereum code): (((range="endofrange", startref="ix_ch09-asciidoc6")))(((range="endofrange", startref="ix_ch09-asciidoc5")))
[source,python]
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@ -360,7 +360,7 @@ 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 decentralized 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 decentralized. 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 decentralized 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 decentralized. 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.
myarbrough@oreilly.com
10 years ago