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The First Feature Complete Privacy Stack is Here
Alpha is live: a fully feature-complete, privacy-first network. The infrastructure is in place, privacy is native to the protocol, and developers can now build truly private applications.
Nine years ago, we set out to redesign blockchain for privacy. The goal: create a system institutions can adopt while giving users true control of their digital lives. Privacy band-aids are coming to Ethereum (someday), but it’s clear we need privacy now, and there’s an arms race underway to build it. Privacy is complex, it’s not a feature you can bolt-on as an afterthought. It demands a ground-up approach, deep tech stack integration, and complete decentralization.
In November 2025, the Aztec Ignition Chain went live as the first decentralized L2 on Ethereum, it’s the coordination layer that the execution layer sits on top of. The network is not operated by the Aztec Labs or the Aztec Foundation, it’s run by the community, making it the true backbone of Aztec.
With the infrastructure in place and a unanimous community vote, the network enters Alpha.
Alpha is the first Layer 2 with a full execution environment for private smart contracts. All accounts, transactions, and the execution itself can be completely private. Developers can now choose what they want public and what they want to keep private while building with the three privacy pillars we have in place across data, identity, and compute.
These privacy pillars, which can be used individually or combined, break down into three core layers:
Alpha is feature complete–meaning this is the only full-stack solution for adding privacy to your business or application. You build, and Aztec handles the cryptography under the hood.
It’s Composable. Private-preserving contracts are not isolated; they can talk to each other and seamlessly blend both private and public state across contracts. Privacy can be preserved across contract calls for full callstack privacy.
No backdoor access. Aztec is the only decentralized L2, and is launching as a fully decentralized rollup with a Layer 1 escape hatch.
It’s Compliant. Companies are missing out on the benefits of blockchains because transparent chains expose user data, while private networks protect it, but still offer fully customizable controls. Now they can build compliant apps that move value around the world instantly.
Developers can explore our privacy primitives across data, identity, and compute and start building with them using the documentation here. Note that this is an early version of the network with known vulnerabilities, see this post for details. While this is the first iteration of the network, there will be several upgrades that secure and harden the network on our path to Beta. If you’d like to learn more about how you can integrate privacy into your project, reach out here.
To hear directly from our Cofounders, join our live from Cannes Q&A on Tuesday, March 31st at 9:30 am ET. Follow us on X to get the latest updates from the Aztec Network.
On Wednesday 17 March 2026 our team discovered a new vulnerability in the Aztec Network. Following the analysis, the vulnerability has been confirmed as a critical vulnerability in accordance with our vulnerability matrix.
The vulnerability affects the proving system as a whole, and is not mitigated via public re-execution by the committee of validators. Exploitation can lead to severe disruption of the protocol and theft of user funds.
In accordance with our policy, fixes for the network will be packaged and distributed with the “v5” release of the network, currently planned for July 2026.
The actual bug and corresponding patch will not be publicly disclosed until “v5.”
Aztec applications and portals bridging assets from Layer 1s should warn users about the security guarantees of Alpha, in particular, reminding users not to put in funds they are not willing to lose. Portals or applications may add additional security measures or training wheels specific to their application or use case.
We will shortly establish a bug tracker to show the number and severity of bugs known to us in v4. The tracker will be updated as audits and security researchers discover issues. Each new alpha release will get its own tracker. This will allow developers and users to judge for themselves how they are willing to use the network, and we will use the tracker as a primary determinant for whether the network is ready for a "Beta" label.
We have identified a vulnerability in barretenberg allowing inclusion of incorrect proofs in the Aztec Network mempool, and ask all nodes to upgrade to versions v.4.1.2 or later.
We’d like to thank Consensys Diligence & TU Vienna for a recent discovery of a separate vulnerability in barretenberg categorized as medium for the network and critical for Noir:
We have published a fixed version of barretenberg.
We’d also like to thank Plainshift AI for discovery, reproduction, and reporting of one more vulnerability in the Aztec Network and their ongoing work to help secure the network.
Decentralization is not just a technical property of the Aztec Network, it is the governing principle.
No single team, company, or individual controls how the network evolves. Upgrades are proposed in public, debated in the open, and approved by the people running the network. Decentralized sequencing, proving, and governance are hard-coded into the base protocol so that no central actor can unilaterally change the rules, censor transactions, or appropriate user value.
The governance framework that makes this possible has three moving parts: Aztec Improvement Proposal (AZIP), Aztec Upgrade Proposal (AZUP), and the onchain vote. Together, they form a pipeline that takes an idea to a live protocol change, with multiple independent checkpoints along the way.
Every upgrade starts with an AZIP. AZIPs are version-controlled design documents, publicly maintained on GitHub, modeled on the same EIP process that has governed Ethereum since its earliest days. Anyone is encouraged to suggest improvements to the Aztec Network protocol spec.
Before a formal proposal is opened, ideas live in GitHub Discussions, an open forum where the community can weigh in, challenge assumptions, and shape the direction of a proposal before it hardens into a spec. This is the virtual town square: the place where the network's future gets debated in public, not decided behind closed doors.
The AZIP framework is what decentralization looks like in practice. Multiple ideas can surface simultaneously, get stress-tested by the community, and the strongest ones naturally rise. Good arguments win, not titles or seniority. The process selects for quality discussion precisely because anyone can participate and everything is visible.
Once an AZIP is formalized as a pull request, it enters a structured lifecycle: Draft, Ready for Discussion, then Accepted or Rejected. Rejected AZIPs are not deleted — they remain permanently in the repository as a record of what was tried and why it was rejected. Nothing gets quietly buried.
Security Considerations are mandatory for all Core, Standard, and Economics AZIPs. Proposals without them cannot pass the Draft stage. Security is structural, not an afterthought.
Once Core Contributors, a merit-based and informal group of active protocol contributors, have reviewed an AZIP and approved it for inclusion, it gets bundled into an AZUP.
An AZUP takes everything an AZIP described and deploys it — a real smart contract, real onchain actions. Each AZUP includes a payload that encodes the exact onchain changes that will occur if the upgrade is approved. Anyone can inspect the payload on a block explorer and see precisely what will change before voting begins.
The payload then goes to sequencers for signaling. Sequencers are the backbone of the network. They propose blocks, attest to state, and serve as the first governance gate for any upgrade. A payload must accumulate enough signals from sequencers within a fixed round to advance. The people actually running the network have to express coordinated support before any change reaches a broader vote.
Once sequencers signal quorum, the proposal moves to tokenholders. Sequencers' staked voting power defaults to "yea" on proposals that came through the signaling path, meaning opposition must be active, not passive. Any sequencer or tokenholder who wants to vote against a proposal must explicitly re-delegate their stake before the voting snapshot is taken. The system rewards genuine engagement from all sides.
For a proposal to pass, it must meet quorum, a supermajority margin, and a minimum participation threshold, all three. If any condition is unmet, the proposal fails.
Even after a proposal passes, it does not execute immediately. A mandatory delay gives node operators time to deploy updated software, allows the community to perform final checks, and reduces the risk of sudden uncoordinated changes hitting the network. If the proposal is not executed within its grace period, it expires.
Failed AZUPs cannot be resubmitted. A new proposal must be created that directly addresses the feedback received. There is no way to simply retry and hope for a different result.
The teams building the network have no special governance power. Sequencers, tokenholders, and Core Contributors are the governing actors, each playing a distinct and non-redundant role.
No single party can force or block an upgrade. Sequencers can withhold signals. Tokenholders can vote nay. Proposals not executed within the grace period expire on their own.
This is decentralization working as intended. The network upgrades not because a team decides it should, but because the people running it agree that it should.
If you want to help shape what Aztec becomes, the forum is open. The proposals are public. The town square is yours.
Follow Aztec on X to stay up to date on the latest developments.
Aztec is novel code — the bleeding edge of cryptography and blockchain technology. As the first decentralized L2 on Ethereum, Aztec is powered by a global network of sequencers and provers. Decentralization introduces some novel challenges in how security is addressed; there is no centralized sequencer to pause or a centralized entity who has power over the network. The rollout of the network reflects this, with distinct goals at each phase.
Ignition
Validate governance and decentralized block building work as intended on Ethereum Mainnet.
Alpha
Enable transactions at 1TPS, ~6s block times and improve the security of the network via continual ongoing audits and bug bounty. New releases of the alpha network are expected regularly to address any security vulnerabilities. Please note, every alpha deployment is distinct and state is not migrated between Alpha releases.
Beta
We will transition to Beta once the network scales to >10 TPS, with reduced block times while ensuring 99.9% uptime. Additionally, the transition requires no critical bugs disclosed via bug bounty in 3 months. State migrations across network releases can be considered.
TL;DR: The roadmap from Ignition to Alpha to Beta is designed to reflect the core team's growing confidence in the network's security.
This phased approach lets us balance ecosystem growth while building security confidence and steadily expanding the community of researchers and tools working to validate the network’s security, soundness and correctness.
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Ultimately, time in production without an exploit is the most reliable indicator of how secure a codebase is.
At the start of Alpha, that confidence is still developing. The core team believes the network is secure enough to support early ecosystem use cases and handle small amounts of value. However this is experimental alpha software and users should not deposit more value than they are willing to lose. Apps may choose to limit deposit amounts to mitigate risk for users.
Audits are ongoing throughout Alpha, with the goal to achieve dual external audits across the entire codebase.
The table below shows current security and audit coverage at the time of writing.
The main bug bounty for the network is not yet live, other than for the non-cryptographic L1 smart contracts as audits are ongoing. We encourage security researchers to responsibly disclose findings in line with our security policy .
As the audits are still ongoing, we expect to discover vulnerabilities in various components. The fixes will be packaged and distributed with the “v5” release.
If we discover a Critical vulnerability in “v4” in accordance with the following severity matrix, which would require the change of verification keys to fix, we will first alert the portal operators to pause deposits and then post a message on the forum, stating that the rollup has a vulnerability.
Aztec uses a hybrid execution model, handling private and public execution separately — and the security considerations differ between them.
As per the audit table above, it is clear that the Aztec Virtual Machine (AVM) has not yet completed its internal and external audits. This is intentional as all AVM execution is public, which allows it to benefit from a “Training Wheel” — the validator re-execution committee.
Every 72 seconds, a collection of newly proposed Aztec blocks are bundled into a "checkpoint" and submitted to L1. With each proposed checkpoint, a committee of 48 staking validators randomly selected from the entire set of validators (presently 3,959) re-execute all txs of all blocks in the checkpoint, and attest to the resulting state roots. 33 out of 48 attestations are required for the checkpoint proposal to be considered valid. The committee and the eventual zk proof must agree on the resultant state root for a checkpoint to be added to the proven chain. As a result, an attacker must control 33/48 of any given committee to exploit any bug in the AVM.
The only time the re-execution committee is not active is during the escape hatch, where the cost to propose a block is set at a level which attempts to quantify the security of the execution training wheel. For this version of the alpha network, this is set a 332M AZTEC, a figure intended to approximate the economic protection the committee normally provides, equivalent to roughly 19% of the un-staked circulating supply at the time of writing. Since the Aztec Foundation holds a significant portion of that supply, the effective threshold is considerably higher in practice.
A key design assumption is that just-in-time bribery of the sequencer committee is impractical and the only ****realistic attack vector is stake acquisition, not bribery.
Assuming a sequencer set size of 4,000 and a committee that rotates each epoch (~38.4mins) from the full sequencer set using a Fisher-Yates shuffle seeded by L1 RANDAO we can see the probability and amount of stake required in the table below.
To achieve a 99% probability of controlling at least one supermajority within 3 days, an attacker would need to control approximately 55.4% of the validator set - roughly 2,215 sequencers representing 443M AZTEC in stake. Assuming an exploit is successful their stake would likely de-value by 70-80%, resulting in an expected economic loss of approximately 332M AZTEC.
To achieve only a 0.5% probability of controlling at least one supermajority within 6 months, an attacker would need to control approximately 33.88% of the validator set.
The practical effect of this training wheel is that the network can exist while there are known security issues with the AVM, as long as the value an attacker would gain from any potential exploit is less than the cost of acquiring 332M AZTEC.
The training wheel allows security researchers to spend more time on the private execution paths that don’t benefit from the training wheel and for the network to be deployed in an alpha version where security researchers can attempt to find additional AVM exploits.
In concrete terms, the training wheel means the Alpha network can reasonably secure value up to around 332M AZTEC (~$6.5M at the time of writing).
Ecosystem builders should keep the above limits in mind, particularly when designing portal contracts that bridge funds into the network.
Portals are the main way value will be bridged into the alpha network, and as a result are also the main target for any exploits. The design of portals can allow the network to secure far higher value. If a portal secures > 332M AZTEC and allows all of its funds to be taken in one withdrawal without any rate limits, delays or pause functionality then it is a target for an AVM exploit attack.
If a portal implements a maximum withdrawal per user, pause functionality or delays for larger withdrawals it becomes harder for an attacker to steal a large quantum of funds in one go.
The Aztec Alpha code is ready to go. The next step is for someone in the community to submit a governance proposal and for the network to vote on enabling transactions. This is decentralization working as intended.
Once live, Alpha will run at 1 TPS with roughly 6 second block times. Audits are still ongoing across several components, so keep deposits small and only put in what you're comfortable losing.
On the security side, a 48-validator re-execution committee provides the main protection during Alpha, requiring 33/48 consensus on every 72-second checkpoint. Successfully attacking the AVM would require controlling roughly 55% of the validator set at a cost of around 332M AZTEC, putting the practical security ceiling at approximately $6.5M.
Alpha is about growing the ecosystem, expanding the security of the network, and accumulating the one thing no audit can shortcut: time in production. This is the network maturing in exactly the way it was designed to as it progresses toward Beta.
The Ignition Chain launched late last year, as the first fully decentralized L2 on Ethereum– a huge milestone for decentralized networks. The team has reinvented what true programmable privacy means, building the execution model from the ground up— combining the programmability of Ethereum with the privacy of Zcash in a single execution environment.
Since then, the network has been running with zero downtime with 3,500+ sequencers and 50+ provers across five continents. With the infrastructure now in place, the network is fully in the hands of the community, and the culmination of the past 8 years of work is now converging.
Major upgrades have landed across four tracks: the execution layer, the proving system, the programming language, Noir, and the decentralization stack. Together, these milestones deliver on Aztec’s original promise, a system where developers can write fully programmable smart contracts with customizable privacy.
The infrastructure is in place. The code is ready. And we’re ready to ship.
The execution layer delivers on Aztec's core promise: fully programmable, privacy-preserving smart contracts on Ethereum.
A complete dual state model is now in place–with both private and public state. Private functions execute client-side in the Private Execution Environment (PXE), running directly in the user's browser and generating zero-knowledge proofs locally, so that private data never leaves the original device. Public functions execute on the Aztec Virtual Machine (AVM) on the network side.
Aztec.js is now live, giving developers a full SDK for managing accounts and interacting with contracts. Native account abstraction has been implemented, meaning every account is a smart contract with customizable authentication rules. Note discovery has been solved through a tagging mechanism, allowing recipients to efficiently query for relevant notes without downloading and decrypting everything on the network.
Contract standards are underway, with the Wonderland team delivering AIP-20 for tokens and AIP-721 for NFTs, along with escrow contracts and logic libraries, providing the production-ready building blocks for the Alpha Network.
The proving system is what makes Aztec's privacy guarantees real, and it has deep roots.
In 2019, Aztec's cofounder Zac Williamson and Chief Scientist Ariel Gabizon introduced PLONK, which became one of the most widely used proving systems in zero-knowledge cryptography. Since then, Aztec's cryptographic backend, Barretenberg, has evolved through multiple generations, each facilitating faster, lighter, and more efficient proving than the last. The latest innovation, CHONK (Client-side Highly Optimized ploNK), is purpose-built for proving on phones and browsers and is what powers proof generation for the Alpha Network.
CHONK is a major leap forward for the user experience, dramatically reducing the memory and time required to generate proofs on consumer devices. It leverages best-in-class circuit primitives, a HyperNova-style folding scheme for efficiently processing chains of private function calls, and Goblin, a hyper-efficient purpose-built recursion acceleration scheme. The result is that private transactions can be proven on the devices people actually use, not just powerful servers.
This matters because privacy on Aztec means proofs are generated on the user's own device, keeping private data private. If proving is too slow or too resource-intensive, privacy becomes impractical. CHONK makes it practical.
Decentralization is what makes Aztec's privacy guarantees credible. Without it, a central operator could censor transactions, introduce backdoors, or compromise user privacy at will.
Aztec addressed this by hardcoding decentralized sequencing, proving, and governance directly into the base protocol. The Ignition Chain has proven the stability of this consensus layer, maintaining zero downtime with over 3,500 sequencers and 50+ provers running across five continents. Aztec Labs and the Aztec Foundation run no sequencers and do not participate in governance.
Noir 1.0 is nearing completion, bringing a stable, production-grade language within reach. Aztec's own protocol circuits have been entirely rewritten in Noir, meaning the language is already battle-tested at the deepest layer of the stack.
Internal and external audits of the compiler and toolchain are progressing in parallel, and security tooling including fuzzers and bytecode parsers is nearly finished. A stable, audited language means application teams can build on Alpha with confidence that the foundation beneath them won't shift.
The code for Alpha Network, a functionally complete and raw version of the network, is ready.
The Alpha Network brings fully programmable, privacy-preserving smart contracts to Ethereum for the first time. It's the culmination of years of parallel work across the four tracks in the Aztec Roadmap. Together, they enable efficient client-side proofs that power customizable smart contracts, letting users choose exactly what stays private and what goes public.
No other project in the space is close to shipping this.
The code is written. The network is running. All the pieces are in place. The governance proposal is now live on the forum and open for discussion. Read through it, ask questions, poke holes, and help shape the path forward.
Once the community is aligned, the proposal moves to a vote. This is how a decentralized network upgrades. Not by a team pushing a button, but by the people running it.
Programmable privacy will unlock a renaissance in onchain adoption. Real-world applications are coming and institutions are paying attention. Alpha represents the culmination of eight years of intense work to deliver privacy on Ethereum.
Now it needs to be battle-tested in the wild.
View the updated product roadmap here and join us on Thursday, March 5th, at 3 pm UTC on X to hear more about the most recent updates to our product roadmap.
Alpha is live: a fully feature-complete, privacy-first network. The infrastructure is in place, privacy is native to the protocol, and developers can now build truly private applications.
Nine years ago, we set out to redesign blockchain for privacy. The goal: create a system institutions can adopt while giving users true control of their digital lives. Privacy band-aids are coming to Ethereum (someday), but it’s clear we need privacy now, and there’s an arms race underway to build it. Privacy is complex, it’s not a feature you can bolt-on as an afterthought. It demands a ground-up approach, deep tech stack integration, and complete decentralization.
In November 2025, the Aztec Ignition Chain went live as the first decentralized L2 on Ethereum, it’s the coordination layer that the execution layer sits on top of. The network is not operated by the Aztec Labs or the Aztec Foundation, it’s run by the community, making it the true backbone of Aztec.
With the infrastructure in place and a unanimous community vote, the network enters Alpha.
Alpha is the first Layer 2 with a full execution environment for private smart contracts. All accounts, transactions, and the execution itself can be completely private. Developers can now choose what they want public and what they want to keep private while building with the three privacy pillars we have in place across data, identity, and compute.
These privacy pillars, which can be used individually or combined, break down into three core layers:
Alpha is feature complete–meaning this is the only full-stack solution for adding privacy to your business or application. You build, and Aztec handles the cryptography under the hood.
It’s Composable. Private-preserving contracts are not isolated; they can talk to each other and seamlessly blend both private and public state across contracts. Privacy can be preserved across contract calls for full callstack privacy.
No backdoor access. Aztec is the only decentralized L2, and is launching as a fully decentralized rollup with a Layer 1 escape hatch.
It’s Compliant. Companies are missing out on the benefits of blockchains because transparent chains expose user data, while private networks protect it, but still offer fully customizable controls. Now they can build compliant apps that move value around the world instantly.
Developers can explore our privacy primitives across data, identity, and compute and start building with them using the documentation here. Note that this is an early version of the network with known vulnerabilities, see this post for details. While this is the first iteration of the network, there will be several upgrades that secure and harden the network on our path to Beta. If you’d like to learn more about how you can integrate privacy into your project, reach out here.
To hear directly from our Cofounders, join our live from Cannes Q&A on Tuesday, March 31st at 9:30 am ET. Follow us on X to get the latest updates from the Aztec Network.
The Ignition Chain launched late last year, as the first fully decentralized L2 on Ethereum– a huge milestone for decentralized networks. The team has reinvented what true programmable privacy means, building the execution model from the ground up— combining the programmability of Ethereum with the privacy of Zcash in a single execution environment.
Since then, the network has been running with zero downtime with 3,500+ sequencers and 50+ provers across five continents. With the infrastructure now in place, the network is fully in the hands of the community, and the culmination of the past 8 years of work is now converging.
Major upgrades have landed across four tracks: the execution layer, the proving system, the programming language, Noir, and the decentralization stack. Together, these milestones deliver on Aztec’s original promise, a system where developers can write fully programmable smart contracts with customizable privacy.
The infrastructure is in place. The code is ready. And we’re ready to ship.
The execution layer delivers on Aztec's core promise: fully programmable, privacy-preserving smart contracts on Ethereum.
A complete dual state model is now in place–with both private and public state. Private functions execute client-side in the Private Execution Environment (PXE), running directly in the user's browser and generating zero-knowledge proofs locally, so that private data never leaves the original device. Public functions execute on the Aztec Virtual Machine (AVM) on the network side.
Aztec.js is now live, giving developers a full SDK for managing accounts and interacting with contracts. Native account abstraction has been implemented, meaning every account is a smart contract with customizable authentication rules. Note discovery has been solved through a tagging mechanism, allowing recipients to efficiently query for relevant notes without downloading and decrypting everything on the network.
Contract standards are underway, with the Wonderland team delivering AIP-20 for tokens and AIP-721 for NFTs, along with escrow contracts and logic libraries, providing the production-ready building blocks for the Alpha Network.
The proving system is what makes Aztec's privacy guarantees real, and it has deep roots.
In 2019, Aztec's cofounder Zac Williamson and Chief Scientist Ariel Gabizon introduced PLONK, which became one of the most widely used proving systems in zero-knowledge cryptography. Since then, Aztec's cryptographic backend, Barretenberg, has evolved through multiple generations, each facilitating faster, lighter, and more efficient proving than the last. The latest innovation, CHONK (Client-side Highly Optimized ploNK), is purpose-built for proving on phones and browsers and is what powers proof generation for the Alpha Network.
CHONK is a major leap forward for the user experience, dramatically reducing the memory and time required to generate proofs on consumer devices. It leverages best-in-class circuit primitives, a HyperNova-style folding scheme for efficiently processing chains of private function calls, and Goblin, a hyper-efficient purpose-built recursion acceleration scheme. The result is that private transactions can be proven on the devices people actually use, not just powerful servers.
This matters because privacy on Aztec means proofs are generated on the user's own device, keeping private data private. If proving is too slow or too resource-intensive, privacy becomes impractical. CHONK makes it practical.
Decentralization is what makes Aztec's privacy guarantees credible. Without it, a central operator could censor transactions, introduce backdoors, or compromise user privacy at will.
Aztec addressed this by hardcoding decentralized sequencing, proving, and governance directly into the base protocol. The Ignition Chain has proven the stability of this consensus layer, maintaining zero downtime with over 3,500 sequencers and 50+ provers running across five continents. Aztec Labs and the Aztec Foundation run no sequencers and do not participate in governance.
Noir 1.0 is nearing completion, bringing a stable, production-grade language within reach. Aztec's own protocol circuits have been entirely rewritten in Noir, meaning the language is already battle-tested at the deepest layer of the stack.
Internal and external audits of the compiler and toolchain are progressing in parallel, and security tooling including fuzzers and bytecode parsers is nearly finished. A stable, audited language means application teams can build on Alpha with confidence that the foundation beneath them won't shift.
The code for Alpha Network, a functionally complete and raw version of the network, is ready.
The Alpha Network brings fully programmable, privacy-preserving smart contracts to Ethereum for the first time. It's the culmination of years of parallel work across the four tracks in the Aztec Roadmap. Together, they enable efficient client-side proofs that power customizable smart contracts, letting users choose exactly what stays private and what goes public.
No other project in the space is close to shipping this.
The code is written. The network is running. All the pieces are in place. The governance proposal is now live on the forum and open for discussion. Read through it, ask questions, poke holes, and help shape the path forward.
Once the community is aligned, the proposal moves to a vote. This is how a decentralized network upgrades. Not by a team pushing a button, but by the people running it.
Programmable privacy will unlock a renaissance in onchain adoption. Real-world applications are coming and institutions are paying attention. Alpha represents the culmination of eight years of intense work to deliver privacy on Ethereum.
Now it needs to be battle-tested in the wild.
View the updated product roadmap here and join us on Thursday, March 5th, at 3 pm UTC on X to hear more about the most recent updates to our product roadmap.
Privacy has emerged as a major driver for the crypto industry in 2025. We’ve seen the explosion of Zcash, the Ethereum Foundation’s refocusing of PSE, and the launch of Aztec’s testnet with over 24,000 validators powering the network. Many apps have also emerged to bring private transactions to Ethereum and Solana in various ways, and exciting technologies like ZKPassport that privately bring identity on-chain using Noir have become some of the most talked about developments for ushering in the next big movements to the space.
Underpinning all of these developments is the emerging consensus that without privacy, blockchains will struggle to gain real-world adoption.
Without privacy, institutions can’t bring assets on-chain in a compliant way or conduct complex swaps and trades without revealing their strategies. Without privacy, DeFi remains dominated and controlled by advanced traders who can see all upcoming transactions and manipulate the market. Without privacy, regular people will not want to move their lives on-chain for the entire world to see every detail about their every move.
While there's been lots of talk about privacy, few can define it. In this piece we’ll outline the three pillars of privacy and gives you a framework for evaluating the privacy claims of any project.
True privacy rests on three essential pillars: transaction privacy, identity privacy, and computational privacy. It is only when we have all three pillars that we see the emergence of a private world computer.
Transaction privacy means that both inputs and outputs are not viewable by anyone other than the intended participants. Inputs include any asset, value, message, or function calldata that is being sent. Outputs include any state changes or transaction effects, or any transaction metadata caused by the transaction. Transaction privacy is often primarily achieved using a UTXO model (like Zcash or Aztec’s private state tree). If a project has only the option for this pillar, it can be said to be confidential, but not private.
Identity privacy means that the identities of those involved are not viewable by anyone other than the intended participants. This includes addresses or accounts and any information about the identity of the participants, such as tx.origin, msg.sender, or linking one’s private account to public accounts. Identity privacy can be achieved in several ways, including client-side proof generation that keeps all user info on the users’ devices. If a project has only the option for this pillar, it can be said to be anonymous, but not private.
Computation privacy means that any activity that happens is not viewable by anyone other than the intended participants. This includes the contract code itself, function execution, contract address, and full callstack privacy. Additionally, any metadata generated by the transaction is able to be appropriately obfuscated (such as transaction effects, events are appropriately padded, inclusion block number are in appropriate sets). Callstack privacy includes which contracts you call, what functions in those contracts you’ve called, what the results of those functions were, any subsequent functions that will be called after, and what the inputs to the function were. A project must have the option for this pillar to do anything privately other than basic transactions.
Bitcoin ushered in a new paradigm of digital money. As a permissionless, peer-to-peer currency and store of value, it changed the way value could be sent around the world and who could participate. Ethereum expanded this vision to bring us the world computer, a decentralized, general-purpose blockchain with programmable smart contracts.
Given the limitations of running a transparent blockchain that exposes all user activity, accounts, and assets, it was clear that adding the option to preserve privacy would unlock many benefits (and more closely resemble real cash). But this was a very challenging problem. Zcash was one of the first to extend Bitcoin’s functionality with optional privacy, unlocking a new privacy-preserving UTXO model for transacting privately. As we’ll see below, many of the current privacy-focused projects are working on similar kinds of private digital money for Ethereum or other chains.
Now, Aztec is bringing us the final missing piece: a private world computer.
A private world computer is fully decentralized, programmable, and permissionless like Ethereum and has optional privacy at every level. In other words, Aztec is extending all the functionality of Ethereum with optional transaction, identity, and computational privacy. This is the only approach that enables fully compliant, decentralized applications to be built that preserve user privacy, a new design space that we see as ushering in the next Renaissance for the space.
Private digital money emerges when you have the first two privacy pillars covered - transactions and identity - but you don’t have the third - computation. Almost all projects today that claim some level of privacy are working on private digital money. This includes everything from privacy pools on Ethereum and L2s to newly emerging payment L1s like Tempo and Arc that are developing various degrees of transaction privacy
When it comes to digital money, privacy exists on a spectrum. If your identity is hidden but your transactions are visible, that's what we call anonymous. If your transactions are hidden but your identity is known, that's confidential. And when both your identity and transactions are protected, that's true privacy. Projects are working on many different approaches to implement this, from PSE to Payy using Noir, the zkDSL built to make it intuitive to build zk applications using familiar Rust-like syntax.
Private digital money is designed to make payments private, but any interaction with more complex smart contracts than a straightforward payment transaction is fully exposed.
What if we also want to build decentralized private apps using smart contracts (usually multiple that talk to each other)? For this, you need all three privacy pillars: transaction, identity, and compute.
If you have these three pillars covered and you have decentralization, you have built a private world computer. Without decentralization, you are vulnerable to censorship, privileged backdoors and inevitable centralized control that can compromise privacy guarantees.
What exactly is a private world computer? A private world computer extends all the functionality of Ethereum with optional privacy at every level, so developers can easily control which aspects they want public or private and users can selectively disclose information. With Aztec, developers can build apps with optional transaction, identity, and compute privacy on a fully decentralized network. Below, we’ll break down the main components of a private world computer.
A private world computer is powered by private smart contracts. Private smart contracts have fully optional privacy and also enable seamless public and private function interaction.
Private smart contracts simply extend the functionality of regular smart contracts with added privacy.
As a developer, you can easily designate which functions you want to keep private and which you want to make public. For example, a voting app might allow users to privately cast votes and publicly display the result. Private smart contracts can also interact privately with other smart contracts, without needing to make it public which contracts have interacted.
Transaction: Aztec supports the optionality for fully private inputs, including messages, state, and function calldata. Private state is updated via a private UTXO state tree.
Identity: Using client-side proofs and function execution, Aztec can optionally keep all user info private, including tx.origin and msg.sender for transactions.
Computation: The contract code itself, function execution, and call stack can all be kept private. This includes which contracts you call, what functions in those contracts you’ve called, what the results of those functions were, and what the inputs to the function were.
A decentralized network must be made up of a permissionless network of operators who run the network and decide on upgrades. Aztec is run by a decentralized network of node operators who propose and attest to transactions. Rollup proofs on Aztec are also run by a decentralized prover network that can permissionlessly submit proofs and participate in block rewards. Finally, the Aztec network is governed by the sequencers, who propose, signal, vote, and execute network upgrades.
A private world computer enables the creation of DeFi applications where accounts, transactions, order books, and swaps remain private. Users can protect their trading strategies and positions from public view, preventing front-running and maintaining competitive advantages. Additionally, users can bridge privately into cross-chain DeFi applications, allowing them to participate in DeFi across multiple blockchains while keeping their identity private despite being on an existing transparent blockchain.
This technology makes it possible to bring institutional trading activity on-chain while maintaining the privacy that traditional finance requires. Institutions can privately trade with other institutions globally, without having to touch public markets, enjoying the benefits of blockchain technology such as fast settlement and reduced counterparty risk, without exposing their trading intentions or volumes to the broader market.
Organizations can bring client accounts and assets on-chain while maintaining full compliance. This infrastructure protects on-chain asset trading and settlement strategies, ensuring that sophisticated financial operations remain private. A private world computer also supports private stablecoin issuance and redemption, allowing financial institutions to manage digital currency operations without revealing sensitive business information.
Users have granular control over their privacy settings, allowing them to fine-tune privacy levels for their on-chain identity according to their specific needs. The system enables selective disclosure of on-chain activity, meaning users can choose to reveal certain transactions or holdings to regulators, auditors, or business partners while keeping other information private, meeting compliance requirements.
The shift from transparent blockchains to privacy-preserving infrastructure is the foundation for bringing the next billion users on-chain. Whether you're a developer building the future of private DeFi, an institution exploring compliant on-chain solutions, or simply someone who believes privacy is a fundamental right, now is the time to get involved.
Follow Aztec on X to stay updated on the latest developments in private smart contracts and decentralized privacy technology. Ready to contribute to the network? Run a node and help power the private world computer.
The next Renaissance is here, and it’s being powered by the private world computer.
After eight years of solving impossible problems, the next renaissance is here.
We’re at a major inflection point, with both our tech and our builder community going through growth spurts. The purpose of this rebrand is simple: to draw attention to our full-stack privacy-native network and to elevate the rich community of builders who are creating a thriving ecosystem around it.
For eight years, we’ve been obsessed with solving impossible challenges. We invented new cryptography (Plonk), created an intuitive programming language (Noir), and built the first decentralized network on Ethereum where privacy is native rather than an afterthought.
It wasn't easy. But now, we're finally bringing that powerful network to life. Testnet is live with thousands of active users and projects that were technically impossible before Aztec.
Our community evolution mirrors our technical progress. What started as an intentionally small, highly engaged group of cracked developers is now welcoming waves of developers eager to build applications that mainstream users actually want and need.
A brand is more than aesthetics—it's a mental model that makes Aztec's spirit tangible.
Renaissance means "rebirth"—and that's exactly what happens when developers gain access to privacy-first infrastructure. We're witnessing the emergence of entirely new application categories, business models, and user experiences.
The faces of this renaissance are the builders we serve: the entrepreneurs building privacy-preserving DeFi, the activists building identity systems that protect user privacy, the enterprise architects tokenizing real-world assets, and the game developers creating experiences with hidden information.
This next renaissance isn't just about technology—it's about the ethos behind the build. These aren't just our values. They're the shared DNA of every builder pushing the boundaries of what's possible on Aztec.
Agency: It’s what everyone deserves, and very few truly have: the ability to choose and take action for ourselves. On the Aztec Network, agency is native
Genius: That rare cocktail of existential thirst, extraordinary brilliance, and mind-bending creation. It’s fire that fuels our great leaps forward.
Integrity: It’s the respect and compassion we show each other. Our commitment to attacking the hardest problems first, and the excellence we demand of any solution.
Obsession: That highly concentrated insanity, extreme doggedness, and insatiable devotion that makes us tick. We believe in a different future—and we can make it happen, together.
Just as our technology bridges different eras of cryptographic innovation, our new visual identity draws from multiple periods of human creativity and technological advancement.
Our new wordmark embodies the diversity of our community and the permissionless nature of our network. Each letter was custom-drawn to reflect different pivotal moments in human communication and technological progress.
Together, these letters tell the story of human innovation: each era building on the last, each breakthrough enabling the next renaissance. And now, we're building the infrastructure for the one that's coming.
We evolved our original icon to reflect this new chapter while honoring our foundation. The layered diamond structure tells the story:
The architecture echoes a central plaza—the Roman forum, the Greek agora, the English commons, the American town square—places where people gather, exchange ideas, build relationships, and shape culture. It's a fitting symbol for the infrastructure enabling the next leap in human coordination and creativity.
From the Mughal and Edo periods to the Flemish and Italian Renaissance, our brand imagery draws from different cultures and eras of extraordinary human flourishing—periods when science, commerce, culture and technology converged to create unprecedented leaps forward. These visuals reflect both the universal nature of the Renaissance and the global reach of our network.
But we're not just celebrating the past —we're creating the future: the infrastructure for humanity's next great creative and technological awakening, powered by privacy-native blockchain technology.
Join us to ask questions, learn more and dive into the lore.
Join Our Discord Town Hall. September 4th at 8 AM PT, then every Thursday at 7 AM PT. Come hear directly from our team, ask questions, and connect with other builders who are shaping the future of privacy-first applications.
Take your stance on privacy. Visit the privacy glyph generator to create your custom profile pic and build this new world with us.
Stay Connected. Visit the new website and to stay up-to-date on all things Noir and Aztec, make sure you’re following along on X.
The next renaissance is what you build on Aztec—and we can't wait to see what you'll create.
Noir, the universal language for zero-knowledge applications, is now in beta.
Noir was originally created to solve the two-brain problem for ZK circuits: with previous zero knowledge DSL's, developers were required to understand basic cryptography in addition to reasoning about business logic. The way we described it was needing two brains:
After over a year of development since Noir’s alpha release, we’re ready to present a powerful version of Noir that is:
If you’ve thought about Noir but wasn’t sure about it’s stability, now’s the time to dive in. While Noir remains unaudited and we warn against production use-cases involving financial assets, we believe the DevEx and feature-suite are mature.
> Discover Noir with Noir Guardians
> Get started with Noir documentation at noir-lang.org
Noir has never been more fun or usable for writing games, identity solutions, and much more that allow for privacy on-chain:
Noir is designed to be familiar to a wide swath of developers, which is why it’s based on Rust. You won’t feel like you’re learning to program again, you’ll just start programming in ZK.
Abstract Circuit Intermediate Representation (ACIR) allows for multiple crypto-providing backends. Noir is Aztec network friendly, not Aztec network only. Plug into any crypto backend you’d like.
awesome-noir boasts a collection of core cryptographic primitives written by best-in-class cryptographers. Take advantage of what your fellow devs have already built, then pay it forward with your own contributions.
Versioned releases: Noir comes released with numbered versions, providing its users the flexibility to choose and settle on a certain snapshot of the language and freeing developers’ minds from the need to constantly keep track of breaking changes. Refer to GitHub to learn more.
Continuous integration testing: Noir is developed with a comprehensive set of integration tests that minimizes the probability of unintentionally breaking existing features with new features. Refer to GitHub to learn more.
Over the development cycles since Alpha, numerous features were introduced to the Noir language and Noir's tooling, including but not limited to:
UltraPlonk Integration: The UltraPlonk proving backend by Aztec enables fast proving speeds and gives Noir developers access to natively optimized gadgets like Keccak256 and ECDSA signature verifications. This unlocks a variety of use-cases such as ECrecover, Ethereum Storage Proofs, and zkWebAuthn. Read the announcement to learn more. While UltraPlonk is the default, Noir supports integration with any backends where the community has been developing integrations with the likes of Halo2, Gnark, etc.
NoirJS: A Javascript package for building privacy-preserving applications that work in web browsers. This major milestone essentially means you can build user-ready web apps with Noir. Read the announcement to learn more.
Unconstrained Functions: Noir supports the development of unconstrained functions using the same language syntax. This means developers can define and write computations that execute outside of circuits, enabling more highly optimized circuits and programs. Read the announcement to learn more.
VS Code Extension: This extension helps developers write, understand, and improve Noir code with features such as:
Read the announcement and download the extension to start using it.
Extended Grammar: From basic control flow like if-else and for-loops to composite data types like structs and traits, Noir supports a wide set of syntaxes that you may expect coming from other programming languages to ease developers building their zero-knowledge applications. Read the Noir docs to learn more.
Standard Library: Re-use trusted and efficient implementations of common primitives without re-implementing cryptography from scratch. Noir comes with a comprehensive standard library covering primitives for hashing, signature verification, merkle proofs, elliptic curve arithmetics, etc. Developed by world class engineers from Aztec Labs and the Noir community, importable right off the shelf. Read the documentation to learn more.
A Noir workflow consists of three stages: Compilation, Execution and Proving.
Compilation is where the user’s program is converted into a sequence of Abstract Circuit Intermediate Representation (ACIR) opcodes for execution and proving that follows. This is done by the Noir compiler, designed with effective circuit optimizing logic and fast compilation.
Execution is where each opcode is executed and the values that each opcode produces is saved, generating proof inputs for proving that follows. This is done by Noir’s Abstract Circuit Virtual Machine (ACVM), a component within the Noir stack.
Proving is where the saved values along with the sequence of opcodes is sent to a proving backend, which generates a proof of the program being executed with said input values. This is done by the proving backend of choice.
Noir enables developers to write, test and compile optimized circuits easily, where they are then handed over to a proving backend of developers’ choice for blazinging fast proving. The default proving backend is the UltraPlonk-based Barretenberg developed and maintained by Aztec Labs.
A quick reference of proving times of common Noir primitives are detailed as below:
A Noir user flow typically starts from developers compiling and distributing the compiled artifacts as a part of their applications to users, where users then execute the application and prove their execution. Execute and Prove times combined hence represent what application users are expected to experience when interacting with applications built with Noir.
Note that execution times depend largely on the Noir stack, while circuit sizes and prove times depend largely on the proving backend of choice. The results were gathered using Noir v0.21.0 paired with the default UltraPlonk-based Barretenberg proving backend on M3 Macbook Pro.
UltraPlonk-based Barretenberg contains small fixed costs for circuits that are amortized in complex circuits. For example, a Noir program doing 1 Keccak256 hash has a circuit size of 55k constraints, while a program that does 100 Keccak256 hashes has a circuit size of 1.8m constraints, rather than 5.5m constraints. This also applies when primitives are mix-and-matched, not just when the same primitive is used at scale.
Expect different results if a different proving backend is used, or when Barretenberg undergoes a significant change (e.g. upgrading from UltraPlonk to UltraHonk).
As a general reference for cross checking performance of Noir programs not listed above, the compilation, execution and proving times for Noir programs spanning different circuit sizes are detailed below:
The Noir technology stack is the main contributor to compilation and execution times, while the proving backend of choice is the main contributor to proving times.
The benchmarking results were gathered using Noir v0.21.0 paired with the default UltraPlonk-based Barretenberg proving backend on M3 Macbook Pro. Refer to Github for more benchmarking details.
Noir is now entering its Beta phase of maturity for developers to start building applications and projects using the language, but that is far from being the destination.
On the road towards production, a vast amount of effort around language features, tooling additions, performance improvements, security audits are continuously being sketched out for the exciting year to come.
If you have been considering developing a Noir project, now is the prime time to start building with the Noir community towards production and launch alongside Noir 1.0.
We’re proud and excited for you to build with Noir Beta as we have ourselves.
We at Aztec Labs have recently completed rebuilding the entirety of Aztec network’s protocol circuits in Noir (read the announcement to learn more). This is the time for your users to experience on-chain privacy via gaming, voting, identities, and so much more.
Learn Noir on Node Guardians today and check resources and projects on Awesome Noir to get started.
Today we are thrilled to announce that Aztec Network has raised $17 million in Series A financing to bring programmable privacy to Web3.
The round was led by Paradigm with support from existing partners a_capital, Ethereal Ventures, and Libertus Capital, and participation from Variant Fund, Nascent, IMToken, Scalar Capital, Defi Alliance, IOSG Ventures, and ZK Validator, along with leading angels including Anthony Sassano, Stani Kulechov, Bankless, Defi Dad, Mariano Conti, and Vitalik Buterin.
“Privacy is a fundamental right. Aztec’s rollup, powered by their pioneering academic research on Plonk, is solving for high privacy while also allowing access to Ethereum’s DeFi. We’re incredibly pleased to partner with them and help advance this work.”
- Georgios Konstantopoulos, Research Partner and Chief Technology Officer, Paradigm
At Aztec we believe decentralization is premised on individual rights. Without widely accessible privacy, we compromise our ability to choose how we live our lives and earn our livelihoods.
That’s why we’re building Aztec Network to deliver privacy without compromise:
“When we started Aztec, the technology to scale blockchains privately didn’t exist. Since then, we’ve assembled a team of world-class cryptographers who continuously redefine the state-of-the-art. Inventing PLONK — the paradigm-defining universal zk-SNARK — showcases our ability to produce technology that matches our ambitions: unlocking an entire universe of blockchain applications that couldn’t exist without privacy.”
- Zac Williamson, CEO and Cofounder, Aztec
Our first product was zk.money, a private transfer protocol built on Aztec. Since launch, zk.money has had over 20,000 registered users, 50,000 transactions, and $35 million in total deposits, all while being 96% cheaper than existing private transfer protocols.
We are now excited to announce Aztec Connect, the first private bridge for Ethereum’s decentralized finance ecosystem. It allows users to confidentially access world-class DeFi services on Ethereum with up to 100x cost savings, all while strengthening Aztec’s existing privacy guarantees.
At launch, Aztec Connect extends the capabilities of zk.money, adding functionality from blue-chip DeFi partners. Soon thereafter, the Connect SDK will allow any Ethereum project to permissionlessly integrate Aztec, unlocking instant privacy and cost-savings.
“We are excited to bring Element’s fixed rates to L2 by integrating with Aztec’s zk-rollup technology. Users will benefit from the same privacy they have come to expect from zk.money with the option to earn fixed rates on their shielded balances, all while saving up to 80–90% in gas fees over L1.”
- Jonny Rhea, CTO and Cofounder, Element Finance
Aztec Connect accomplishes the above while maintaining two significant advantages over other scaling solutions:
“Privacy needs an active financial market to be useful. Aztec Connect was designed with this in mind — its goal is to deliver value to users of existing DeFi protocols by adding iron-clad privacy guarantees and reducing transaction costs.”
- Joe Andrews, Head of Product and Cofounder, Aztec
Proceeds from the Series A will be used for network decentralization, Aztec Connect Grants, and continued development of our class-leading zero knowledge proving systems.
We are grateful for the community of users and developers supporting Aztec’s mission to build the programmable privacy layer for Ethereum and Web3.
To join our community or develop on Aztec Connect, please follow us on Twitter, find us on Discord, and check out the Aztec Connect Starter on Github.
We are always looking for talented and passionate contributors to Aztec. If you’re interested in joining our mission, browse our full time roles here.
Aztec Network is the first private ZK-rollup on Ethereum, enabling decentralized applications to access privacy and scale. Aztec’s rollup is secured by its industry-standard PLONK proving mechanism used by the leading zero-knowledge scaling projects.
For press inquiries please reach out to jon@aztecprotocol.com.
A full media kit can be found here.
How do you benchmark SNARKs?
It’s a problem because different SNARKs will perform differently on various circuits — it’s not a matter of ‘PLONK is 5x faster than Sonic every time’.
Well, a critical measure is how efficiently a SNARK can verify a hash operation. But why are hashes important? This article describes how zero-knowledge assets are stored in the Two-Tree Model, and therefore why fast hashes in SNARKs are mission-critical.
Before explaining how the Two-Tree Model works, here’s a reminder of what a Merkle tree actually is.
Remember, the purpose of a Merkle Tree is to generate a single short digest (hash) of many pieces of data, so that if asked, one can prove that any one piece of data is ‘guaranteed’ by that hash without revealing all the other pieces of data.
In the diagram below, data pieces A, B, C and D are separately hashed. Next, each pair is hashed together (turning 4 hashes into two hashes). Finally, those two hashes are hashed to form the ‘Merkle Root’.
The Merkle Root changes if and only if a single piece of data changes (i.e. if A, B, C or D are modified / edited). Here’s the picture to have in mind:
We introduce the classical model for storing ZK Assets.
This system is built around a UTXO model like Bitcoin — i.e. each asset is recorded via so-called ‘notes’ of ownership. An asset with $1,000 total global supply is held in the form of one-or-more notes by each owner.
Alice may hold $10 of this asset in (say) three notes: $7, $2 and $1. Transferring ownership involves a ‘join split’ transaction which takes input notes (e.g. say the $7 and $2 notes above), and printing new output notes (say $8 and $1).
Instead of creating output notes and destroying input notes, we instead record this process in two trees —
The idea is — instead of deleting a note from the Note Tree, you need to check whether that note also turns up in the Nullifier Tree to work out if it’s already spent. If it’s not there, it’s still spendable.
A join-split transaction adds the output notes to the Note Tree, and the input notes to the Nullifier Tree.
Let’s take a closer look at these structures.
Locations in Tree = ~2³⁰ leaves (dense Merkle Tree)
The first tree — the Note Tree — determines the current state of all data inside the system — smart contracts, registers of ownership of assets — everything. For now, let’s focus just on recording the ownership of assets through notes.
Suppose Alice sends Bob 50 zkDai and the Note Tree has slots 1, 2, … n filled up. Then the following is added to the Note Tree:
Encrypt (
{
owner: [Bob's Address], asset: 0x40a5a9872e73de550516d8ec43c6990f8247441d, amount: 50
}
)Locations in Tree = ~2²⁵⁶ leaves (sparse Merkle Tree)
The second tree — the Nullifier Tree — determines which notes have been spent — we add the following to the Nullifier Tree to mark Alice’s Input Note of 50 zkDai as spent.
Hash (
{
owner: [Alice's Address], asset: 0x40a5a9872e73de550516d8ec43c6990f8247441d, amount: 50
}
)
The ‘random’ nature of the Hash means the note in the nullifier set can’t be traced to the newly-added note in the Note Tree.
The two-tree diagram above is actually slightly misleading in one respect — it shows the spent note being added to position 3 (out of 4) in the Nullifier Tree, at the same location it was originally created in the Note Tree.
However, these two trees have significantly different structures.
The Note Tree is actually encoded as a ‘dense’ Merkle Tree — that is, a tree designed to hold ~2³⁰ notes, and therefore requiring 30 hashes to add a note. You add the notes in the order in which they are created over the lifetime of the asset— first note at position 1, second note at position 2, etc. This tree is ‘dense’ because leaves are all created as immediate next-door neighbours.
The Nullifier Tree, however, looks very different — addresses, instead of running in order, are determined by the hash of the nullifier note data (detailed above). This of of course means that the Nullifier Tree is a sparse Merkle tree — that is, a tree with 2²⁵⁶ theoretically-available leaves — each containing the number 0. The note is added at the address determined by that hash — that’s right, the note hash’s value *also* doubles as its location in the tree. In other words, the Nullifier Note is placed into the Nullifier Tree amid a wilderness of zeros.
Notice that this means that the position of a note in the Nullifier Tree (i.e. being marked as spent) is ≠ the position in the Note Tree.
There are two excellent reasons for this:
Observation: Even though the Nullifier Tree has 2²⁵⁶ locations, and therefore 256 hashes between a leaf and the Merkle Root, most of the locations always hold the default value 0 (i.e. most locations are unused). This allows us to get the number of hashes needing verification nearer to 30, rather than 256.
The following computation is indicative only — AZTEC is actually going to use more SNARK-friendly hashes e.g. Pedersen commitments.
But to complete the exercise:
Each SHA-256 hash in PLONK requires ~27,000 gates for a 64 byte input, so 60 hashes consume ~1.6m gates. The actual smart-contract logic can often be run in a handful of gates — sometimes 10s, 100s, or 1,000s of gates depending on the smart contract in question.
That leaves hashing algorithms dominating > 99% of the computation. And that is why benchmarking SNARKs on hashing algorithms is the crucial barometer of speed.
We’re on the lookout for talented engineers and applied cryptographers. If joining our mission to bring scalable privacy to Ethereum excites you — get in touch with us at hello@aztecprotocol.com.
