Tezos tz5 Post-Quantum Account Goes Live on Testnet

Steady attention without excessive speculation.

The tz5 address uses ML-DSA-44, a lattice-based signature scheme that NIST standardized in FIPS 204. It shipped with Ushuaia, the 21st Tezos protocol upgrade, which activated on mainnet on June 30. For now, the tz5 post-quantum account sits behind a feature flag and runs on testnets only.

What the tz5 Post-Quantum Account Brings to Tezos

Every Tezos address today leans on elliptic-curve cryptography. That includes tz1, tz2, tz3, and the newer tz4 accounts. A powerful quantum computer could, in theory, break those curves using Shor’s algorithm.

tz5 answers that risk directly. Instead of an elliptic curve, it signs with ML-DSA-44, a lattice-based scheme. Because no known quantum algorithm cracks lattices efficiently, the keys should hold up far longer.

Nomadic Labs, Trilitech, and Functori built the feature together. According to the Nomadic Labs announcement, the code passed through on-chain governance without a fork. The protocol hash is PsUshuai9QapM5TGj1JpuVGkdxz5GykdnEvS6Rh8SUVrARvZLCY.

How ML-DSA-44 Resists Quantum Attacks

ML-DSA-44 was once known as CRYSTALS-Dilithium. NIST finalized it in FIPS 204 in August 2024. It is the lowest parameter set in the ML-DSA family, rated at roughly 128-bit security.

The scheme rests on the hardness of finding short vectors in high-dimensional lattices. Shor’s algorithm does not apply to that problem. As a result, lattice signatures stay secure even against a large quantum machine.

Still, the safety comes with a size cost. An ML-DSA-44 public key runs about 1.3 KB, and a signature about 2.4 KB. By contrast, an Ed25519 key is 32 bytes and its signature 64 bytes. So every tz5 operation carries more data, which raises storage and gas costs on chain.

Tezos leans on a formally verified Rust library called libcrux-ml-dsa for the math. According to core developers on the Tezos Agora forum, performance stays close to a normal tz1 account for everyday operations.

What tz5 Accounts Can and Cannot Do

On testnets where the flag is on, a tz5 post-quantum account works like a regular wallet. It can send transfers, call smart contracts, delegate, and stake. In other words, ordinary user operations already function.

Yet there are firm limits for now. A tz5 account cannot register as a delegate. It also cannot serve as a consensus key. So baking and validation stay off-limits until later work lands.

Existing accounts feel no impact at all. tz1, tz2, tz3, and tz4 keys keep working exactly as before, per the Octez account documentation. Above all, nobody has to migrate, and no funds move automatically.

Where Ushuaia Fits in the Tezos Roadmap

Tezos upgrades itself through on-chain governance in roughly two-month cycles. Ushuaia is the 21st such upgrade. It activated at block 13,857,889 on June 30, 2026, at 00:31:52 UTC.

Beyond tz5, the upgrade raised data availability bandwidth by about 15 times. That change feeds the wider Tezos X plan for high-throughput rollups. Meanwhile, tz5 adds forward-looking cryptography to the same release.

The plan is deliberately phased. First, ML-DSA-44 arrives behind a flag. Next come stateful addresses for key attachment and rotation. Finally, older schemes would retire only if a quantum threat actually appears.

“With Ushuaia, Tezos Layer 1 does exactly what a modern settlement layer should do: increase data availability for the applications arriving with Tezos X, while preparing the cryptographic migration path long before quantum risk becomes urgent.”

That framing came from Yann Régis-Gianas, Head of Engineering at Nomadic Labs, in Tezos media coverage of the launch.

Muted Market and Community Response

The testnet news did not move the market much. Around July 16, XTZ traded near $0.22 to $0.23, according to aggregator data from CoinGecko and CoinMarketCap. Daily volume stayed in the low millions of dollars.

That calm makes sense. Markets had already absorbed the June 30 mainnet activation, which centered on data availability. So the July tweet read as a developer update rather than a price catalyst.

Community sentiment looked positive but quiet. The official post drew modest engagement, with likes and reposts in the low dozens within hours. On the Agora forum, contributors framed the work as prudent groundwork rather than hype.

None of this is financial advice. Readers should do their own research before acting on any price or investment view.

What Comes Next for the tz5 Post-Quantum Account

For now, the tz5 post-quantum account stays testnet-only, and Tezos has set no firm mainnet date. Instead, the team wants wallets, custodians, and tooling to adapt first. Developers can already generate tz5 accounts on Ushuaianet through Octez.

Baking support, key rotation, and native multisig with tz5 keys all remain planned rather than shipped. So the next milestones will show whether the phased migration holds up in practice. Until then, Tezos sits among the first major chains to test a production-grade post-quantum account.