What is World ID
Proof of Personhood for the AI era. A decentralized protocol that proves you are a unique, real human while protecting your privacy
1. World ID Overview
World ID is a decentralized Proof of Personhood protocol provided by World. In an era of rapidly advancing AI and bots, it was developed to prove online that "you are a real, unique human" while protecting your privacy.
Traditional identity verification required submitting personal information like passports or driver's licenses to third parties. This posed privacy risks and made it difficult to completely prevent multiple account creation.
World ID combines iris verification using a dedicated device called the "Orb" with zero-knowledge proof cryptography to prove you are a real, unique human without revealing any personal information.
3 Key Features of World ID
- 1.One Person, One ID: Technically impossible for one person to obtain multiple IDs
- 2.Privacy Protection: Prove you're human without revealing personal information
- 3.Decentralized: An open protocol independent of any company or government
2. Why Proof of Personhood is Needed Now
New Challenges in the AI Era
With the rapid advancement of generative AI, AI-generated text, images, and videos are becoming indistinguishable from human-created content. Large language models like ChatGPT can generate natural, human-like text, making it technically easy for AI bots to impersonate humans on social media.
This situation causes the following problems:
- •Misinformation Spread: Mass posting of fake news and misinformation by AI bots
- •Opinion Manipulation: Artificial trend manipulation through multiple bot accounts
- •Fraud & Impersonation: Increasing fraud through impersonation of real people
- •Trust Erosion: Inability to determine who is a real human online
The Solution: Proof of Personhood
"Proof of Personhood" is a concept and technology for proving that a user is a real, unique human online. It guarantees the user is not an AI or bot, and not multiple accounts controlled by the same person.
World ID is a leading system that implements Proof of Personhood. By using iris biometrics, it reliably identifies a unique human while protecting privacy through zero-knowledge proofs.
3. How One Person, One ID Works
Why Iris Recognition?
World ID uses iris (eye pattern) recognition for the following reasons:
- •Uniqueness: Iris patterns differ for each person, even identical twins
- •Permanence: Remains unchanged from age 2 throughout life
- •High Accuracy: Contains about 10x more information than fingerprints, with extremely low false recognition rates
- •Contactless: Authentication by camera only (hygienic)
IrisCode: Privacy-Preserving Conversion Technology
Iris images captured by the Orb are converted into a unique binary code called "IrisCode". This conversion is one-way and has the following properties:
- •Reconstructing the original iris image from IrisCode is mathematically impossible
- •The same IrisCode is always generated from the same person's iris
- •Extremely low probability of different people having matching IrisCode (collision resistance)
After conversion to IrisCode, the original iris image scanned by the Orb is immediately deleted. Iris images are never stored on servers.
What is Sybil Resistance?
A "Sybil attack" is when one attacker creates multiple fake accounts to abuse a system. World ID's Orb verification achieves high Sybil resistance by physically guaranteeing one ID per person through multiple biometric factors including iris, facial depth, and thermography.
4. Privacy Protection Technology
Zero-Knowledge Proofs
World ID uses a cryptographic technology called "zero-knowledge proofs." This technology allows you to prove you possess certain information without revealing the information itself.
For example, to prove "I am over 20 years old," you traditionally had to show your birth date on a driver's license. With zero-knowledge proofs, you can prove the fact that you are over 20 without revealing your birth date.
Semaphore Protocol
World ID is built on an open-source privacy protocol called Semaphore. Semaphore provides the following capabilities:
- •Anonymous Membership Proof: Prove group membership without revealing which member you are
- •Anonymous Signaling: Perform actions without revealing your identity
- •Double-Spend Prevention: Prevent reuse of the same proof
Why You Can't Be Tracked Across Services (nullifier hash)
Every time you verify with World ID, a different "nullifier hash" is automatically generated for each service. Even with the same World ID, completely different IDs are used on Service A and Service B, making it impossible to link users even if two services collude. This is fundamentally different from Google login, where a single account is used across multiple services.
Information Shared and Not Shared During Verification
Information NOT Shared
- • Name
- • Address
- • Date of birth
- • Phone number
- • Email address
- • Iris image
- • IrisCode (directly)
Facts That Are Proven
- • You are an Orb-verified human
- • This is your first verification (no duplicates)
- • (Optional) You meet specific attribute conditions
5. What World ID Can and Cannot Prove
✓ What CAN Be Proven
- •The account owner is an Orb-verified real human
- •The same person has not created multiple accounts (Sybil resistance)
- •A human created the account, not a bot
- •This is the first verification on this service
✗ What CANNOT Be Proven
- •That account operation is not by AI or bots
- •Whether posts are made by the owner themselves
- •The account owner's real name or identity
- •The accuracy or reliability of posted content
Important Note
World ID proves "one person, one account" and "the owner is a real human," but does not prove how the account is operated. An Orb-verified person can technically have AI post on their behalf. World ID only proves that a real human exists behind the account.
6. Technical Architecture (World Chain)
World Chain
World ID verification information is managed on a dedicated blockchain network called "World Chain." World Chain has the following characteristics:
- •Ethereum L2: Fast and low-cost while inheriting Ethereum's security
- •OP Stack: Optimistic rollup using Optimism's technology stack
- •Decentralized: Open infrastructure independent of any single company
Verification Levels
World ID has multiple verification levels:
Orb Verification (Highest Level)
Verified by capturing multiple biometric factors (iris, facial depth, thermography) with an Orb device. Fully guarantees one person, one ID. Humanary registration requires Orb verification only.
Device Verify
Simple verification completed on smartphone only. Not as strong a one-person-one-ID guarantee as Orb verification, but convenient.
7. Humanary and World ID
Humanary is a profile service only available to those who have completed World's Orb verification. Device Verify (smartphone-only verification) is not accepted.
By registering with Humanary, you can show third parties that "the owner of this account is a real human who has completed Orb verification." This allows you to:
- •Demonstrate credibility to fans and business partners
- •Distinguish yourself from impersonators with multiple accounts
- •Share your World referral code with credibility
For detailed usage information, see the "Creator's Guide".
8. How to Get World ID
To get World ID, you need to download the World App and complete Orb verification.
Getting Started
- 1.Download World App from App Store or Google Play
- 2.Search for the nearest verification location using "Find an Orb" in the app
- 3.Get your iris scanned by the Orb at the location (about 10 seconds)
- 4.World ID issuance complete
In Japan, you can get Orb verification at over 240 locations nationwide. Orbs are installed at stores like au Style, Re.Ra.Ku, ME TOKYO, and X-Mobile.
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