Tezos launches post-quantum testnet; Breitman criticizes skeptics

Tezos deployed TzEL, a post-quantum privacy system, on its testnet to protect encrypted payments and on-chain transaction data from future quantum decryption. The feature is experimental and intended to test performance and integration before any mainnet upgrade.

TzEL is designed to shield private memos and other encrypted transaction fields so that attackers cannot collect ciphertext today and decrypt it later if a powerful quantum computer becomes available. The goal is to reduce the risk of so-called “harvest now, decrypt later” attacks, in which an adversary stores blockchain data now and decodes it once quantum hardware can break current cryptography.

Arthur Breitman, Tezos co-founder, said the project is moving with “a sense of urgency” and criticized voices in the Bitcoin community for downplaying quantum risks. He said some commentators promote what he described as “half-baked crank theories” about quantum mechanics that contradict established physics and warned that several projects remain poorly maintained and may not upgrade their cryptography.

The technical hurdle for post-quantum privacy is scale. Quantum-resistant zero-knowledge proofs such as zk-STARKs are much larger than the proofs used by existing privacy tools, which raises storage and throughput costs. Tezos developers say the network’s data availability layer can absorb larger proofs without increasing load on consensus nodes.

Work is also under way to add post-quantum signature support for user accounts. Developers describe the current deployments as experimental tests to measure verification costs, storage requirements and wallet compatibility. The team said multiple steps are required before any protocol-level rollout to mainnet.

Security firms and quantum researchers have estimated that a cryptographically relevant quantum computer-one able to break elliptic curve signatures used across many blockchains-could appear within several years. A recent technical assessment estimated a so-called “Q-Day” could come as early as 2030, prompting calls across the industry to plan for algorithm upgrades.

Opinions differ on timing and urgency. Michael Shaulov, CEO of a crypto infrastructure firm, argued the technical tools for post-quantum encryption are available and framed the challenge mainly as coordination and deployment. He encouraged the broader internet and crypto ecosystems to adopt post-quantum algorithms sooner rather than later.

Most cryptocurrencies today rely on elliptic curve cryptography for digital signatures. Classical computers cannot feasibly break these schemes, but certain quantum algorithms could recover private keys once sufficiently powerful quantum hardware exists. The industry debate centers on when to move to quantum-resistant primitives and how to upgrade large, decentralized networks without introducing new vulnerabilities.