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Namecoin

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by

Levin Keller

on 19 March 2014

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Transcript of Namecoin

Namecoin
Namecoin
Bitcoin
Open topics
a distributed name service based on bitcoin
The clearing house problem
200$
100$
Bob
Steve
Alice
100$
200$
100$
Maintaining a unique and complete database
A shared database
200$
100$
Bob
Steve
Alice
100$
200$
100$
Propagation:
peer-2-peer distribution by every client
in each transaction the recipient
needs to propagate
contradicting database versions need to be resolved

Contradiction resolution
distributed trustless proof-of-work for versioning of
contradiction free
databases ("mining")
oldest database wins
monetary reward for proof-of-work computation (bitcoins)

Unique, valid (contradiction free), publicly known instance of the database
Spam protection
Every user maintains copy of whole database
costs for storage
costs for propagation and relay

Spam protection
each transaction costs a fee (in bitcoin)
fees set at will by miners (market equilibrium)
fees are added to payout for proof-of-work versioning
Money of the internet?
Bitcoin solves the distributed clearing house problem

Clearing houses are used for many processes:
contracts
escrow services
identity management
claiming of names for dns
...

Features are developed within bitcoin (contracts, escrow) and in extensions or derivatives (namecoin)

Bitcoin is the internet of money
Basic namecoin transactions
secretly reserve a name
publicly claim a name
publicly change the value of a name
User authorization
How does the user verify his identity for database manipulation?
all funds (bitcoins) are credited to public key hashes
the private key allows spending of the funds

Consequences:
any user can have an arbitrary number of accounts
loss of private key makes funds inaccessible or spendable by third party

Trustless
and
without safety net!
Namecoin rules
any currently unclaimed name can be claimed by a transaction signed with a private key
no name reservation can exist twice at a given time
confirmed reservations expire after 36,000 blocks / ~249 days if not renewed
private key used for currently valid public reservation permits change of the corresponding database entries
reservation and modification of database entries are subject to a namecoin fee (spam protection)
private key
Looking up a name
Prerequisites:
complete, valid (contradiction free) copy of current namecoin database (blockchain)

name resolving:
scan the blockchain for mentioning of the name
last occurrence provides current valid entry (e.g. an ip address)

key facts:
changing an entry requires private key
no CA needed
validation of database entries can be done by user (trustless)

all queries are local: time < 10ms
Further applications
Namecoin is a trustless, verifiable storage of contradiction-free information.

Other possible applications are:
identity management
voting
login system
checksum database
web of trust
personal namespace
alias system
transfer ownership of a name to another pubkey
Namecoins
Purpose:
reward for proof-of-work verification
spam protection
buyable proof-of-work

Features:
21,000,000 total supply
gradually declining rate of generation
divisible by 8 digits
merged mining with bitcoin
challenges for namecoin
Squatting
large quanitities of names reserved

No revocation
aquisition of private key allows full name / domain control
no possibility of domain invalidation

Storage of the blockchain
storage shortage mobile devices
high traffic
"lightweight client" may not be feasible
fast growth rates
51% attack
The 51%-attack:
immense continuous computation power allows for 51% hashrate-attack
attackers blockchain is generated faster than public blockchain
Namecoin uses SHA-256 for proof-of-work, same as bitcoin
large bitcoin miners impose threats

added improvements:
merged mining with bitcoin
hash rate of namecoin 70%-90% of bitcoin hash rate
51 attack still possible.
attacker can delete database entries and afterwards claim names
very expensive today
more expensive every day
history of namecoin
first discussion of namecoin in 11/2010
first implementation by "Vince Durham" and "Khal" for a bitcoin-bounty
maintained today by a loose group of activists in:
https://bitcointalk.org/index.php?topic=6017
http://dot-bit.org/forum/
irc://irc.freenode.net/namecoin
challenges for bitcoin
legal issues
digital currencies might be declared illegal
technological advance
bitcoin might be improved by a successor
decline in hashrate leaves namecoin vulnerable
call for contribution
need for experienced c++ developers
implementation of a one-click installer for firefox, chrome, etc.
Join namecoin:
https://bitcointalk.org/index.php?topic=6017
http://dot-bit.org/forum/
irc://irc.freenode.net/namecoin
Full transcript