What is an iris code, and how does it preserve privacy?

What is an iris code? 

An iris code is a compact numeric representation of an individual's unique iris texture. Its bits encode the fine details of the iris, capturing features like the arrangement of crypts, furrows and pigmentations.

Unlike iris images, which are raw, data-rich visual representations, iris codes are stripped-down numeric templates that serve as a digital stand-in for the iris.

How is an iris code generated?

Iris codes are generated through a process that involves capturing a high-resolution image of the iris using a specialized camera. The image is then processed to extract relevant features, and algorithms convert these features into a numeric code.

To verify World ID, Worldcoin uses a custom biometric imaging device called the Orb to securely generate iris codes. Learn more about the Orb’s hardware and custom telephoto lens. 

The iris code is generated in such a way that even small variations in the iris texture result in significantly different iris codes, helping to ensure uniqueness. Importantly, irises from two different people, even direct family members (including identical twins), look completely different.

Are iris codes the same as iris images?

Iris codes are not the same as iris images. Iris images are raw visual representations of the iris, while iris codes are numeric representations derived from those images.

Iris codes are much smaller in size and contain much less data than iris images, making them more privacy preserving and more efficient for 1:N biometric authentication.

How do iris codes preserve privacy?

Iris codes enhance privacy in multiple ways. As noted above, iris codes contain much less data than iris images, making it extremely difficult for anyone to reverse-engineer the original iris image from the code. 

Importantly, the use of iris codes also allows for the complete deletion of iris images. This is the case for the World ID verification process. By default, the Orb promptly deletes all iris images after the creation of the iris code.

Iris codes help make it possible for biometrics to be used to securely verify an individual’s uniqueness while preserving their privacy.

Where are World ID iris codes stored?

Iris codes used to verify World ID are stored on (AWS) servers where they are encrypted at rest. For privacy, actions taken with World ID are not linked to a person's iris code.