The Application and Challenges of zk-SNARKs Technology in Digital Identity

Nowadays, the application of zk-SNARKs technology in digital identity systems has gradually become mainstream. Various identity projects based on zk-SNARKs are developing user-friendly software packages that allow users to prove they hold a valid identification without revealing identity details. The number of World ID users, who protect their privacy through biometrics and zk-SNARKs, has recently surpassed 10 million. Some government projects have also begun to apply zk-SNARKs technology in the digital identity field.

Although zk-SNARKs technology provides important protection for privacy, there are still some risks and challenges:

1. zk-SNARKs alone cannot achieve complete anonymity. If the application assigns a unique ID to each user and the identification system follows the "one person, one identity" principle, users may only be able to have one account, which actually reduces anonymity.

2. zk-SNARKs cannot prevent identification from being coerced and disclosed. If someone is forced to reveal a secret value, all their activities may be tracked.

3. zk-SNARKs cannot address non-privacy risks, such as coverage of identification systems, issues of multiple nationalities, hacking attacks, etc.

4. Relying solely on "proof of wealth" to prevent witch attacks is not enough. In certain scenarios, such as universal basic income and governance decisions, we still need some form of identification system.

An ideal identity system should strike a balance between privacy protection and attack prevention. The cost of obtaining N identities being N² may be a better compromise. A multi-identity system, whether explicit ( based on social graphs ) or implicit ( where multiple identities coexist ), could be a viable way to achieve this goal.

In the future, the "one person, one identification" project may integrate with a social graph-based identification system, providing initial support for the latter, thereby constructing a more secure and scalable global distributed identification system.