Zooko's triangle is a diagram named after Zooko Wilcox-O'Hearn which sets out the possible tradeoffs for a system for giving names to participants in a network protocol. At the vertices of the triangle are three properties that are generally considered desirable for such names:

• Secure: The quality that there is one, unique and specific entity to which the name maps. For instance, domain names are unique because there is just one party able to prove that they are the owner of each domain name.
• Decentralized: The lack of a centralised authority for determining the meaning of a name. Instead, measures such as a Web of trust
  Web of trust
  In cryptography, a web of trust is a concept used in PGP, GnuPG, and other OpenPGP-compatible systems to establish the authenticity of the binding between a public key and its owner. Its decentralized trust model is an alternative to the centralized trust model of a public key infrastructure ,...
  
   are used.
• Human-meaningful: The quality of meaningfulness and memorability to the users of the naming system. Domain names and nicknaming are naming systems that are highly memorable.

Of these three properties, proponents of Zooko's triangle argue that no single kind of name can achieve more than two. So the edges of the triangles represent the three possible choices for a naming scheme:

• Decentralized and human-meaningful: this is true of nicknames people choose for themselves
• Secure and human-meaningful: this is the property that domain names and URLs aim for
• Secure and decentralized: this is a property of OpenPGP key fingerprints

Although no one kind of name can have all three properties, Petname

Petname

Petname systems are naming systems that claim to possess all three naming properties - global, secure, and memorable . Software that uses such a system can satisfy all three requirements...

 systems demonstrate that one can build a naming system by dynamically translating between different possible kinds of names.

Namecoin and Zooko's triangle properties

Namecoin, a distributed naming system based on Bitcoin

Bitcoin

Bitcoin is a decentralized, peer-to-peer network over which users make transactions that are tracked and verified through this network. The word Bitcoin also refers to the digital currency implemented as the currency medium for user transactions over this network...

 technology, meets all three qualities in Zooko's triangle.

External links

• Zooko Wilcox-O'Hearn, Names: Decentralized, Secure, Human-Meaningful: Choose Two - the essay highlighting this difficulty
• Mark Steigler, An Introduction to Petname Systems - a clear introduction
• Nick Szabo, Secure Property Titles argues that all three properties can be achieved up to the limits of Byzantine fault tolerance
  Byzantine fault tolerance
  Byzantine fault tolerance is a sub-field of fault tolerance research inspired by the Byzantine Generals' Problem, which is a generalized version of the Two Generals' Problem....
  
  .
• Bob Wyman, The Persistence of Identity: Updating Zooko's Pyramid
• Paul Crowley, Squaring Zooko's Triangle
• Aaron Swartz, Squaring the Triangle using a technique from Bitcoin
  Bitcoin
  Bitcoin is a decentralized, peer-to-peer network over which users make transactions that are tracked and verified through this network. The word Bitcoin also refers to the digital currency implemented as the currency medium for user transactions over this network...