Zucoin transaction v3 scheduled for post-quantum cryptography as advanced research moves into transaction v2

27 May 2026

Zucoin is making major advancements across 2 transaction types: the current transaction v2 format and transaction v3, the next transaction type focused on post-quantum cryptography and many powerful capabilities.

This update explains why selected capabilities from the transaction v3 research pathway are being moved into the current transaction format sooner than originally planned.

There is a lot happening in parallel right now, from regulatory work and marketplace readiness to post-quantum cryptography planning and third-party integration pathways.

The short version: Zucoin transaction v3 is being scheduled around post-quantum cryptography integrated into every Zucoin transaction, while many features from that cutting-edge research are being added to the current transaction v2 structure, to get them into users' hands sooner.

The key details are outlined below.

Transaction v3 roadmap: The transaction v3 roadmap schedules post-quantum cryptography to be integrated into every Zucoin transaction
Current transaction v2 acceleration: Many features from the transaction v3 research path are being ported into the existing transaction v2 structure
Developer upside: Fewer near-term changes for third-party integrations while advanced abilities become available sooner
New capabilities: Work includes transaction behaviors such as expiring transactions without requiring smart asset contracts
Post-quantum preparation: A large part of the groundwork for larger quantum-safe transactions is already underway
Bitcoin napkin math: A quick stress test on ways post-quantum cryptography could affect Bitcoin, including larger signatures, effective block capacity, batching, layer 2, or protocol changes
Indicative target: Zucoin is currently targeting late 2026 for post-quantum cryptography rollout, subject to technical and operational changes

Transaction v3 defines the post-quantum transaction path

Zucoin transaction v3 is being scheduled as the transaction generation that integrates post-quantum cryptography into every Zucoin transaction.

That makes the transaction v3 upgrade more than a normal feature release.

It is the planned transaction path for a world where every transfer needs to be ready for post-quantum cryptography by default.

As part of that work, Zucoin's product team found a simpler way to port some advanced transaction v3 capabilities back into the existing transaction v2 structure.

This matters because it lets the team deliver useful new transaction behavior without requiring every part of the ecosystem to wait for the full post-quantum transaction v3 migration.

It also reduces backwards-compatibility work.

Instead of keeping all research output locked behind a larger future transaction v3 rollout, more of the system can keep moving forward inside the structure users and third-party integrations already depend on.

For builders, this means fewer immediate integration changes while still opening access to more powerful transaction behaviors.

Why Zucoin's 2022 transaction v2 upgrade mattered

Some long-time Zucoin users and readers will remember the 1st major move from Zucoin transaction v1 to transaction v2 in 2022.

That shift was delicate because it changed how transaction amounts were handled internally.

The system moved away from ordinary computer number calculations, often called floating point calculations, toward text-based string number handling.

That made it possible to support very high precision amounts, including 32 decimal places.

That precision is a key part of how Zucoin and Splitchain support smaller, fine-grained transfers while helping keep operating costs low and wallet-to-wallet transfers fee-free.

The current acceleration from transaction v3 into transaction v2 builds on that earlier foundation.

It keeps the proven transaction v2 structure in place while selectively adding more advanced transaction behavior from the post-quantum transaction v3 research stream where it can be done cleanly.

This is why the 2022 transaction v2 upgrade still matters today.

Less migration work, faster capability rollout

The strategic upside is simple: this should reduce a meaningful amount of migration and backwards-compatibility work.

Instead of forcing every new capability to wait for the larger post-quantum transaction v3 rollout, the team can bring selected features forward into today's transaction v2 structure.

That helps Zucoin and Splitchain development, and it also helps third parties.

There should be fewer changes for external systems to make before they can use many of the newer abilities.

One important example is expiring transactions.

These can help create safer and cleaner transaction flows without requiring a separate smart asset contract layer for every use case.

Because the transaction v3 work is scheduled around post-quantum cryptography for every Zucoin transaction, this also means a large chunk of the groundwork for that switch has already been completed.

Post-quantum cryptography changes the size equation

Post-quantum cryptography is not a small change.

For transaction systems, the critical change is often quantum-safe signing and authentication, not encryption alone.

It affects transaction design, data size, network capacity, storage, communication timing, and user experience.

In August 2024, the U.S. National Institute of Standards and Technology released its 1st finalized post-quantum cryptography standards, including ML-KEM for general encryption and ML-DSA for digital signatures.

Zucoin and MyZucoins have been monitoring post-quantum cryptography progress for many years, including the standards process, algorithm maturity, library support, and what a real-world migration would mean for transaction systems.

The 2024 standards were an important milestone, but standards do not instantly upgrade the internet.

It takes time for production code, cryptography libraries, operating systems, servers, wallets, hardware, network protocols, audit processes, and developer tooling to support new cryptographic foundations safely.

That kind of change propagates gradually through the wider world of computer systems.

First the standards mature, then stable implementations appear, then major platforms add support, then businesses and networks test, audit, deploy, and migrate live systems.

That is why early preparation matters.

The standards give the wider technology industry a clearer foundation for migration, but they also bring real engineering trade-offs.

For Zucoin, a normal transaction is typically around 1KB in size.

A transaction using post-quantum cryptography, such as a NIST-standardized lattice-based approach, is expected to be much larger.

Current planning estimates suggest it could be roughly 30 to 40 times the size of a normal transaction, depending on the final algorithms and implementation choices.

The size increase is the hard engineering problem.

That size increase is why the team has been doing deeper work on how the Splitchain network will handle quantum-safe transaction formats while preserving speed, efficiency, and practical everyday use.

The Zucoin product team is comfortable with the direction development is heading for the Splitchain network and Zucoin Wallet support for post-quantum cryptography.

Bitcoin napkin math shows why Zucoin's efficiency and parallel transactions matter

To understand why this matters, it helps to compare the problem with Bitcoin's base layer at a high level.

Let's briefly dive into some technical number crunching that shows the depth of the task the industry is facing, so hang tight for this next section.

Bitcoin's base layer is commonly described as processing around 3.3 to 7 transactions per second, with a roughly 10-minute average block interval and a capacity model constrained by block size and block weight.

Recent efficient SegWit and Taproot-heavy blocks can average a little above 7 transactions per second, which is why the examples below use both recent per-block data and a rounded 7 transactions per second stress case.

SegWit changed Bitcoin's capacity accounting by introducing a weight-based model, with BIP 141 setting the limit at 4,000,000 weight units, often described as 1 million virtual bytes.

That means raw block size and effective block capacity are different, because witness data is counted differently.

That is the relevant point for post-quantum migration: transaction size, compatibility, and protocol coordination all matter.

This means plain "bytes per transaction" and actual Bitcoin block capacity are not the same thing.

Any post-quantum estimate has to distinguish between raw data size and effective transaction weight.

For a recent public data point, YCharts listed Bitcoin average transactions per block at 4,739.36 for 25 May 2026, while BTC.network's 14-21 May 2026 block-space report measured 4,382 transactions per block, 1.50MB average blocks, and 95.6% fullness for that week.

If a near-full Bitcoin block has about 956,000 virtual bytes used (1,000,000 virtual bytes times 95.6% fullness) and about 4,382 transactions, the average effective transaction size is roughly 218 virtual bytes: 956,000 divided by 4,382.

The same raw block-size figure gives about 342 raw bytes per transaction: 1.50MB divided by 4,382.

Now apply post-quantum size assumptions to that average.

If the effective transaction weight became 10 times larger, the 4,382 transaction average would fall toward about 438 transactions per block.

At 20 times larger, it would fall toward about 219 transactions per block.

At 40 times larger, it would fall toward about 110 transactions per block.

That is a major capacity reduction on the Bitcoin network.

The 40 times scenario is the simple stress-test version of the earlier calculation.

Rounded to 4,000 ordinary transactions per block for simpler math, 4,000 divided by 40 gives roughly 100 transactions per block.

Of course, these calculations assume Bitcoin migrates to one of the NIST-approved post-quantum cryptography approaches, or an equivalent quantum-safe signature architecture with similar size trade-offs.

Using the same simplified logic, a network operating around 7 transactions per second could behave closer to 0.175 transactions per second at 40 times effective weight, or the equivalent of 1 transaction worth of capacity every 5.7 seconds, still batched into roughly 10-minute Bitcoin blocks.

If demand stayed the same and layer 1 capacity did not materially increase, clearing the same amount of transaction activity could take far longer.

That does not mean Bitcoin's block interval becomes longer.

It means the same amount of demand would need more blocks to clear.

In a simplified backlog model, a normal 1-block to 6-block waiting range of roughly 10 to 60 minutes could stretch by a similar 40 times factor, toward roughly 6.6 to 40 hours until capacity, fees, batching, or other network behavior adapted.

So without increasing Bitcoin's effective block capacity or introducing parallel processing like Zucoin has, a transaction using post-quantum cryptography could, in this simplified demand model, take roughly 6 - 40 hours to settle.

The important caveat is that a final Bitcoin post-quantum design may not map raw signature size into block weight 1-for-1.

For example, NIST's ML-DSA digital signature standard includes public keys from 1,312 to 2,592 bytes and signatures from 2,420 to 4,627 bytes.

A single ML-DSA signature alone does not prove a 30 to 40 times effective-weight increase.

If a future Bitcoin design placed only the new signature data into a witness-discounted area, the effective-weight increase may be far less than that.

If it required larger public keys, extra proofs, multiple signatures, or data counted at full weight, then the effective increase could move much closer to the 30 to 40 times stress-test range.

That is the core issue for Bitcoin and similar crypto systems.

Adding ML-DSA or an equivalent post-quantum signature architecture is not just a matter of swapping a signature algorithm for another.

If the signature and public-key data become much larger, Bitcoin either accepts fewer layer 1 transactions, increases capacity, relies more heavily on batching and layers above Bitcoin, or changes how that data is counted inside the protocol.

Increasing layer 1 capacity has its own consequences.

Larger blocks or higher effective block weight can increase bandwidth, storage, validation, mempool, and block propagation requirements for full nodes, miners, and infrastructure operators.

This is mainly a data-handling and validation burden rather than a direct proof-of-work hashpower multiplier, but over time those higher operating requirements can still create centralisation pressure if fewer people can afford to run reliable infrastructure.

This was one of the core arguments in Bitcoin's block-size debate, where competing views over layer 1 capacity, node costs, and decentralisation resulted in a major community split and the Bitcoin Cash hard fork.

While there is no confirmed final Bitcoin post-quantum design yet, the point is to show some quick back-of-the-napkin calculations explaining why quantum-safe migration is not just a cryptography problem.

It is also a scalability, efficiency, network capacity, storage, infrastructure, and community coordination problem affecting all parts of the ecosystem.

Major crypto networks are starting to plan

The wider crypto industry is now taking the same issue seriously.

In January 2026, Coinbase established an independent advisory board on quantum computing and blockchain resilience, specifically to evaluate quantum risks for crypto networks including Bitcoin and Ethereum.

In April 2026, the same advisory group published a position paper on quantum computing and crypto networks, arguing that current systems are safe today but the industry needs to begin preparing before the risk becomes urgent.

In March 2026, Forbes reported on Google Quantum AI research suggesting that quantum computers could threaten Bitcoin's elliptic-curve cryptography sooner than previously expected, with the resource estimate potentially below 500,000 physical qubits.

The danger is not that ordinary users need to panic today.

The real issue is that network-wide cryptography migrations take time, and waiting until a powerful quantum computer exists would be far too late.

Preparation and migrations have to happen before the pressure arrives.

Why protocol changes are difficult

Bitcoin's own history shows why large protocol and capacity changes need careful planning.

The block-size debate around SegWit was not just a technical discussion.

It was a disagreement over what Bitcoin should optimize for, how much capacity should exist on layer 1, and how much extra resource burden should be placed on the people running the network.

SegWit increased effective capacity through a backwards-compatible soft fork by changing how witness data was counted.

A direct hard increase to the old block-size limit would have been more disruptive, because older nodes would not accept blocks that broke the previous rules.

The major Bitcoin block-size split immediately before SegWit activation resulted in Bitcoin Cash forking from Bitcoin on 1 August 2017, shortly before SegWit activated on the original Bitcoin network later that month.

There was also SegWit2x, a proposed hard fork intended to increase Bitcoin's block size to 2MB after SegWit, but it was cancelled in November 2017 due to lack of consensus.

That history matters because post-quantum migration could create similar trade-offs for many crypto networks: larger transaction data, more bandwidth, more storage, more difficult node operation, more demanding miner infrastructure, and potential pressure toward centralisation if the system is not engineered carefully.

It also means the technical answer is only part of the problem.

Even if the cryptography is clear, communities still have to agree on how to migrate, how to handle old wallets, how much capacity to add, who carries the extra infrastructure cost, and whether the change should happen through a soft fork, hard fork, or some other architecture.

The social migration can be as difficult as the code migration.

Zucoin's approach is to do the groundwork early, keep the migration path practical, and design Splitchain's post-quantum cryptography upgrade path around utilising the existing speed, maintaining low costs, squeezing out more efficiency, and leaning on powerful parallel transaction processing capabilities to offset the added transaction weight.

What this means for Zucoin users and builders

There is no immediate action required from everyday Zucoin users because of this update.

The work is happening behind the scenes so that future changes can be rolled out with less friction and less disruption.

For third-party builders, the acceleration of some features from transaction v3 into transaction v2 is more relevant.

It means newer transaction abilities from the post-quantum transaction v3 research path can arrive through the existing transaction shape, reducing the amount of change required before integrations can use them.

For the wider ecosystem, the post-quantum work is about long-term readiness.

Zucoin is being designed so that quantum-safe transactions can remain fast, low-cost, efficient, and compatible with Splitchain's parallel transaction model.

That is the practical goal.

Timelines can change because this work depends on cryptography standards, implementation testing, network behavior, wallet upgrades, and rollout safety.

At this stage, Zucoin is targeting late 2026 for post-quantum cryptography rollout.

External references

For readers who want to dig deeper into the public background material, these references are useful starting points:

Who do I contact if I have feedback, spotted a bug, or need help?

Contact Zucoin's support team here.

Need priority help with Zucoin or Zutopia?

Zucoin has friendly 1-on-1, pro-level support offered by Z8 Digital.

About Zucoin and Splitchain

Zucoin is a digital asset supported by a self-managed wallet app, designed for direct user control, everyday transfers, and third-party integrations.

Splitchain is Zucoin's crypto system network, built with a focus on speed, cost-efficiency, and practical real-world use.

More information, community insights, and recent news can be found at myzucoins.org and zucoins.com.

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