Namecoin

Namecoin

a distributed name service based on bitcoin

Namecoin

Basic namecoin transactions

Namecoin rules

secretly reserve a name

Namecoins

private key

publicly claim a name

• 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)

publicly change the value of a name

transfer ownership of a name to another pubkey

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

Bitcoin

Maintaining a unique and complete database

The clearing house problem

Open topics

challenges for namecoin

history of namecoin

Further applications

Looking up a name

Money of the internet?

Steve

51% attack

Bob

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

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

Alice

• 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

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

200$

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

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

100$

200$

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

51 attack still possible.

• attacker can delete database entries and afterwards claim names
• very expensive today
• more expensive every day

User authorization

A shared database

Spam protection

Steve

Bob

call for contribution

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!

100$

challenges for bitcoin

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

• need for experienced c++ developers
• implementation of a one-click installer for firefox, chrome, etc.

Alice

legal issues

• digital currencies might be declared illegal

technological advance

• bitcoin might be improved by a successor
• decline in hashrate leaves namecoin vulnerable

200$

100$

200$

Join namecoin:

• https://bitcointalk.org/index.php?topic=6017
• http://dot-bit.org/forum/
• irc://irc.freenode.net/namecoin