Ethereum Foundation Unveils zkAPI for Private AI Payments

The Ethereum Foundation has launched a new system called zkAPI, designed to enable users to pay for AI services without revealing their permanent billing identity. This system, developed in collaboration with the Open Anonymity Project, separates payment authorization from the conversation itself, keeping the provider and the payment layer distinct.

When a user wants to pay for an AI service, they first fund an Ethereum vault, which keeps a private record of the balance and the information needed to spend it. A zero-knowledge proof is then generated to show that sufficient funds are available without identifying the deposit.

The payment server checks the payment authorization and accounts for usage, but does not receive the prompts in this setup. The AI service receives the prompts and responses, as well as a temporary session key, but not the user's billing information. The public blockchain records deposits and withdrawals, but the user's identity is not tied to their payment transactions.

The zkAPI system is currently live on the Ethereum main network, but is still considered experimental. Users should be aware of the potential risks and limitations, including the need to trust that the secret material used in the proof system was handled securely.