Midnight CTO Highlights Private Proof of Stake as AI Raises Security Concerns

Midnight Foundation Chief Technology Officer Sebastien Guillemot has highlighted private proof of stake as a security consideration in the AI era, arguing that identifying token holders and block producers can make them easier targets for attackers.

In an October 31 post, Guillemot also pointed to Cardano’s approach to block production. The network already provides some protection, he explained, because observers cannot know in advance which stake pool will produce a block.

Why Guillemot Raised Private Proof of Stake

Proof of stake is a method used by blockchain networks to select participants who can produce blocks and help maintain the ledger. Depending on the network, token holders may delegate their stake to operators that run the necessary infrastructure.

Guillemot’s comments focus on the information available about those participants. On a public blockchain, addresses and stake distributions can be visible, and other information may connect an address or an operator to a person or organization.

His concern is that such visibility can help attackers identify potential targets. An operator, for example, could face an attempt to steal credentials or gain access to infrastructure used in block production. Guillemot connected the broader risk to the growing importance of AI, without describing a specific attack in his post.

Private proof of stake is an area of research that explores how a network can verify participation while limiting what is revealed about participants or their stake. The exact information protected depends on the design of each protocol.

What Cardano Already Protects

On Cardano, a stake pool can determine locally whether it has been selected to produce a block. The rest of the network can verify the selection when the pool publishes the block with its cryptographic proof.

That means an outside observer cannot determine the selected producer in advance simply by looking at a public schedule. Guillemot cited this property as an example of privacy protection already available in a proof of stake network, while arguing that additional improvements could help protect networks.

The distinction is specific: concealing a block producer’s selection before publication does not make Cardano’s entire stake distribution or all pool activity private.

Research has explored how to extend privacy further. The 2019 Ouroboros Crypsinous paper presented a privacy-preserving proof of stake protocol that uses cryptographic techniques, including zero-knowledge proofs, to help establish eligibility without exposing the underlying private information.

Its authors also analyzed security against adaptive attacks, in which an adversary can choose whom to compromise as the protocol runs. Crypsinous is a research design and was not presented in Guillemot’s post as an activated Cardano or Midnight upgrade.

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Midnight’s Staking Roadmap and Private PoS Research

Midnight uses zero-knowledge technology in applications that can verify information while protecting selected details. That application-level privacy is distinct from concealing who participates in consensus or how much stake they control.

Charles Hoskinson previously identified private proof of stake as a protocol he was working on while discussing development priorities for Midnight. He described an approach that would move through research, specification, simulation and implementation.

Guillemot’s post did not include a design or launch date for private proof of stake on Midnight. Separately, Midnight’s published roadmap targets NIGHT staking and community block production in the first quarter of 2027, with Cardano stake pool operators expected to be able to join as block producers.