- Human-meaningful: Meaningfulness and memorability to the users.
- Decentralized: No need of a centralized authority for determining the meaning of a name.
- Secure: There is one, unique and specific entity to which the name applies.
Zooko Wilcox-O'Hearn conjectured that no single kind of name can achieve more than two. For example: DNSSec, offers a secure, human-meaningful naming scheme, but is not decentralized; .onion addresses and bitcoin addresses, are secure and decentralized but not human-meaningful; and I2P, uses name translation services which are decentralized and provide human-meaningful names - but relies on trusting third parties.
Zooko's conjecture has now been disproven through the creation of systems that exhibit all three properties.
Several systems which exhibit all three properties of Zooko's triangle have now been created, including:
- Computer scientist Nick Szabo' s "Secure Property Titles with Owner Authority" paper illustrated that all three properties can be achieved up to the limits of Byzantine fault tolerance.
- Activist Aaron Swartz described a naming system based on Bitcoin employing Bitcoin's distributed blockchain as a proof-of-work to establish consensus of domain name ownership. These systems remain vulnerable to sybil attacks, but are secure under Byzantine assumptions. Namecoin now implements the concept.
- Zooko Wilcox-O'Hearn. "Names: Decentralized, Secure, Human-Meaningful: Choose Two". Archived from the original on 2001-10-20.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
- Nick Szabo, Secure Property Titles, 1998
- Aaron Swartz, Squaring the Triangle: Secure, Decentralized, Human-Readable Names, Aaron Swartz, January 6, 2011
- Dan Kaminsky, Spelunking the Triangle: Exploring Aaron Swartz’s Take On Zooko’s Triangle, January 13, 2011
- Monero core team (2014-09-19). "OpenAlias". Retrieved 2015-02-03.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
- Zooko Wilcox-O'Hearn, Names: Decentralized, Secure, Human-Meaningful: Choose Two – the essay highlighting this difficulty
- Marc Stiegler, 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.
- 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