Aztec Network
22 Apr
## min read

History of Aztec: Pioneering Privacy in Web3

Aztec from 2017 to 2024 can be seen as a methodical journey toward building a fully private, programmable, and decentralized blockchain network. Aztec mainnet will mark the emergence of applications that weren't possible before – applications that combine the transparency and programmability of blockchain with the privacy necessary for real-world adoption. 

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The Early Days of Aztec (2017)

When Aztec mainnet launches, it will be the first fully private and decentralized L2 on Ethereum. Getting here was a long road: when Aztec started eight years ago, the initial plan was to build an onchain financial service called CreditMint for issuing corporate debt to mid-market enterprises – obviously a distant use case from how we understand Aztec today. When co-founders Zac Williamson, Joe Andrews, Tom Pocock, and Arnaud Schenk, got started, the world of zero-knowledge proving systems and applications weren’t even in their infancy: there was no PLONK, no Noir, no programmable privacy, and it wasn’t clear that demand for onchain privacy was even strong enough to necessitate a new blockchain network. The founders’ initial explorations through CreditMint led to what we know as Aztec today. 

While putting corporate debt onchain might seem unglamorous (or just limited compared with how we now understand Aztec’s capabilities), it was useful, wildly popular, and necessary for the founding team to realized that no serious institution wanted to touch the blockchain without the same privacy assurances that they were accustomed to in the corporate world. Traditional finance is built around trusted intermediaries and middlemen, which of course introduces friction and bottlenecks progress – but offers more privacy assurances than what you see on public blockchains like Ethereum. 

This takeaway led to a bigger understanding: the number of people (not just the number of institutions) who wanted to use the blockchain was limited by a lack of programmable privacy. Aztec was born out of the recognition that everyone – not only corporations – could use permissionless, onchain systems for private transactions, and this could become the default for all online payments. In the words of the CEO, Zac Williamson:

“If you had programmable digital money that had privacy guarantees around it, you could use that to create extremely fast permissionless payment channels for payments on the internet.” 

Equipped with this understanding, Zac and Joe began to specialize. Zac, whose background is in particle physics, went deep on cryptography research and began exploring protocols that could be used to enable onchain privacy. Meanwhile, Joe worked on how to get user adoption for privacy tech, while Arnaud focused on getting the initial CreditMint platform live and recruiting early members of the team. In 2018, Aztec published a proof-of-concept transaction demonstrating the creation and transfer of private assets on Ethereum  – using an early cryptographic protocol that predated modern proving schemes like PLONK. It was a limited example, with just DAI as the test-case (and it could only facilitate private assets, not private identities), but it garnered a lot of early interest from members of the Ethereum community. 

“The Product Needs Drive the Proving Scheme” (2018-2020)

The 2018 version of the Aztec Protocol had three key limitations: it wasn’t programmable, it only supported private data (rather than private data and user-level privacy), and it was expensive, from both a computation and gas perspective. The underlying proving scheme was, in the words of Zac, a “Frankenstein cryptography protocol using older primitives than zk-SNARKs.” These limitations motivated the development of PLONK in 2019, a SNARK-based proving system that is computationally inexpensive, and only requires one universal trusted setup. 

A single universal trusted setup is desirable because it allows developers to utilize a common reference string for all of the programs they might want to instantiate in a circuit; the alternative is a much more cumbersome process of conducting a trusted setup ceremony for each cryptographic circuit. In other words, PLONK enabled programmable privacy for future versions of Aztec. 

PLONK was a big breakthrough, not just for Aztec, but for the wider blockchain community. Today, PLONK has been implemented and extended by teams like zkSync, Polygon, Mina, and more. There is even an entire category of proving systems called PLONKish that all derive from the original 2019 paper. For Aztec specifically, PLONK was also instrumental in paving the way for zk.money and Aztec Connect, a private payment network and private DeFi rollup, which launched in 2021 and 2022 respectively.  

The product needs of Aztec motivated the development of a modern-day proving system. PLONK proofs are computationally cheap to generate, leading not only to lower transaction costs and programmability for developers, but big steps forward for privacy and decentralization. PLONK made it simpler to generate client-side proofs on inexpensive hardware. In the words of Joe, “PLONK [was] developed to keep the middleman away.”  

Making the Blockchain Real (2021-2023)

Between 2021 and 2023, the Aztec team operated zk.money and Aztec Connect. The products were not only vital in illustrating that there was a demand for onchain privacy solutions, but in demonstrating that it was possible to build performant and private networks leveraging PLONK. Joe remarked that they “wanted to test that we could build a viable payments network, where the user experience was on par with a public transaction. Privacy needed to be in the background.” 

Aztec’s early products indicated that there was significant demand for private onchain payments and DeFi – at peak, the rollups had over $20 million in TVL. Both products fit into the vision Zac had to “make the blockchain real.” In his team’s eyes, blockchains are held back from mainstream adoption because you can’t bring consequential, real-world assets onchain without privacy. 

Despite the demand for these networks, the team made the decision to sunset both zk.money and Aztec Connect after recognizing that they could not fully decentralize the networks without massive architectural changes. Zac and Joe don’t believe in “Progressive Decentralization” – the network needs to have no centralized operators from day one. And it wasn’t just the sequencer of these early Aztec products that were centralized – the team also recognized that it would have been impossible for other developers to write programs on Aztec that could compose with each other, because all programs operated on shared state. In 2023, zk.money and Aztec Connect were officially shut down. 

In tandem, the team also began developing Noir (an original brainchild of Kevaundray Wedderbaum). Noir is a Rust-like programming language for writing zero-knowledge circuits that makes privacy technology accessible to mainstream developers. While Noir began as a way to make it easier for developers to write private programs without needing to know cryptography, the team soon realized that the demand for privacy didn’t just apply to applications on the Aztec stack, and that Noir could be a general-purpose DSL for any kind of application that needs to leverage privacy. In the same way that bringing consequential assets and activity onchain “makes the blockchain real,” bringing zero-knowledge technology to any application – onchain or offchain – makes privacy real. The team continued working on Noir, and it has developed into its own product stack today. 

Aztec Today 

Aztec from 2017 to 2024 can be seen as a methodical journey toward building a fully private, programmable, and decentralized blockchain network. The earliest attempt at Aztec as a protocol introduced asset-level privacy, without addressing user-level privacy, or significant programmability. PLONK paved the way for user-level privacy and programmability, which yielded zk.money and Aztec Connect. Noir extended programmability even further, making it easy for developers to build applications in zero-knowledge. But zk.money and Aztec Connect were incomplete without a viable path to decentralization. So, the team decided to build a new network from scratch. Extending on their learnings from past networks, the foundations and findings from continuous R&D efforts of PLONK, and the growing developer community around Noir, they set the stage for Aztec mainnet. 

The fact of the matter is that creating a network that is fully private and decentralized is hard. To have privacy, all data must be shielded cheaply inside of a SNARK. If you want to really embrace the idea of “making the blockchain real” then you should also be able to leverage outside authentication and identity solutions, like Apple ID – and you need to be able to put those technologies inside of a SNARK as well. The number of statements that need to be represented as provable circuits is massive. Then, all of these capabilities need to run inside of a network that is decentralized. The combination of mathematical, technological, and networking problems makes this very difficult to achieve

The technical architecture of Aztec reflects the learnings of the Aztec team. Zac describes Aztec mainnet as a “Russian nesting doll” of products that all add up to a private and decentralized network. Aztec today consists of:

  1. A decentralized Prover and Sequencer network that eliminates central points of control
  2. The Privacy Execution Environment (PXE) that enables client-side proving
  3. Significant innovations in proving systems, including the faster, low-memory proving systems optimized for browser performance

At the network level, there will be many participants in the decentralization efforts of Aztec: provers, sequencers, and node operators. Joe views the infrastructure-level decentralization as a crucial first stage of Aztec’s mainnet launch.

As Aztec goes live, the vision extends beyond private transactions to enabling entirely new categories of applications. The team envisions use cases ranging from consumer lending based on private credit scores to games leveraging information asymmetry, to social applications that preserve user privacy. The next phase will focus on building a robust ecosystem of developers and the next generation of applications on Ethereum using  Noir, the universal language of privacy. 

Aztec mainnet marks the emergence of applications that weren't possible before – applications that combine the transparency and programmability of blockchain with the privacy necessary for real-world adoption. 

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Aztec Network
Aztec Network
31 Mar
xx min read

Announcing the Alpha Network

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. 

What is the Alpha Network?

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: 

  1. Data: The data you hold or send remains private, enabling use cases such as private transactions, RWAs, payments and stablecoins.
  2. Identity: Your identity remains private, enabling accounts that privately connect real world identities onchain, institutional compliance, or financial reporting where users selectively disclose information.
  3. Compute: The actions you take remain private, enabling applications in private finance, gaming, and beyond.

The Key Components  

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.

How Apps Work on Alpha 

  1. Write in Noir, an open-source Rust-like programming language for writing smart contracts. Build contracts with Aztec.nr and mark functions private or public.
  1. Prove on a device. Users execute private logic locally and a ZK proof is generated.
  1. Submit to Aztec. The proof goes to sequencers who validate without seeing the data. Any public aspects are then executed.
  1. Settle on Ethereum. Proofs of transactions on Aztec are settled to Ethereum L1.

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.

Aztec Network
Aztec Network
27 Mar
xx min read

Critical Vulnerability in Alpha v4

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.

State of Alpha security

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.

Additional bug disclosure

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.

Aztec Network
Aztec Network
18 Mar
xx min read

How Aztec Governance Works

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.

The Virtual Town Square

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.

From Proposal to Upgrade

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.

Built-In Delays, Built-In Safety

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.

No Single Point of Control

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 Network
Aztec Network
10 Mar
xx min read

Alpha Network Security: What to Expect

Aztec’s Approach to Security

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.

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.

Security of the Aztec Virtual Machine (AVM)

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.

Quantifying the cost of committee takeover attacks

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.

What does this means for builders?

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.

Conclusion

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.