Ethereum co-founder Vitalik Buterin has released an open-source privacy stack for AI agents, describing a “paranoid mode” for his personal agent harness, pi. The system combines Tor routing, zkAPI anonymous payments, and local prompt rewriting to reduce how much user information is exposed when interacting with large language models.
According to Buterin’s technical update on October 16, 2026, each AI conversation is assigned a separate Tor circuit, while real requests are mixed with random cover traffic to make traffic analysis harder. The daemon is compatible with the OpenAI API, allowing the privacy layer to sit between an AI agent and an external model provider. The agent itself runs inside a bubblewrap sandbox with torsocks, forcing network activity through Tor. Buterin said he is also experimenting with MicroVM technology as another isolation option.
Before prompts reach an external AI provider, a local model rewrites them so that the user’s original wording and style are less identifiable. Buterin used a bring-your-own-local-model arrangement with a qwen model in his demonstration. In a test, the agent was asked to find the five best vegan restaurants in Tallinn and returned a structured table from Google search results. Buterin said, “It’s getting quite usable!” but acknowledged slower response times, especially when starting new sessions.
Despite the safeguards, Buterin admitted Tor is not a perfect solution. He said random cover traffic offers reasonable protection against passive observers, but a coordinated attack involving an AI provider and a Tor guard relay could manipulate request and response timing to break anonymity. He argued that a specialized mixnet with constant cover traffic would be a stronger long-term alternative, though no working implementation or timeline was provided.
The payment component uses zkAPI, which allows users to deposit funds into an Ethereum vault and authorize metered API usage through zero-knowledge proofs without exposing their funding identity. Buterin added that significantly cheaper gas costs for zkAPI deposits and withdrawals are coming to the Ethereum mainnet soon, though no deployment date or exact reduction was specified. zkAPI was introduced on October 1 by the Ethereum Foundation and Open Anonymity Project, and this latest work builds on that system and on earlier privacy experiments Buterin conducted in early October.
