Semaphore vs Aztec Protocol: Privacy Application Scope

Zero-Knowledge Identity Primitive: A minimalist, audited smart contract library for anonymous signaling and group membership. This matters for building lightweight, composable privacy features like anonymous voting or attestations directly into your dApp on L1/L2.

Seamless Smart Contract Integration: Deployed on Ethereum, Arbitrum, Optimism, and Polygon. This matters for teams that need to add privacy to an existing EVM stack without complex client-side proving or a new VM.

Private Smart Contract Platform: A dedicated zkRollup with a privacy-first VM (Aztec VM) enabling confidential state and logic. This matters for applications requiring full transaction privacy (e.g., private DeFi, confidential DAO treasuries) where both amounts and logic must be hidden.

Efficient Batch Proving: Leverages PLONK-based recursion for batching private transactions, achieving ~100+ TPS for confidential computations. This matters for high-throughput private applications where cost-per-private-action is a critical metric.

• Adding anonymous features to a public app (e.g., anonymous governance on Snapshot).
• Lightweight group membership (e.g., proof of humanity in Worldcoin).
• Teams prioritizing auditability, simplicity, and EVM compatibility over full state privacy.

• Building a fully private application from the ground up (e.g., a private AMM or lending protocol).
• Applications requiring confidential amounts, balances, and transaction graphs.
• Projects that can adopt a new VM and client-side proving stack for maximum privacy guarantees.

Specific advantage: Specialized for anonymous identity and signaling via zero-knowledge group membership proofs. This matters for on-chain voting, anonymous DAO participation, and reputation systems where proving membership without revealing identity is the primary goal. Its scope is narrow and optimized for this single, powerful primitive.

Specific advantage: Deployed as a set of Solidity smart contracts on Ethereum L1/L2s. This matters for teams needing lightweight, composable privacy without a separate chain. Projects like Unirep Social and Interep use it for gas-efficient, anonymous attestations directly within their existing EVM stack.

Specific weakness: Does not provide private transactions or confidential state. This matters if your use case requires hiding token amounts, asset types, or smart contract logic. You cannot build a private DEX or confidential DeFi pool with Semaphore alone; it's a tool for identity, not general computation.

Specific advantage: Offers a zk-rollup with a privacy-first VM enabling confidential smart contracts. This matters for private DeFi (zk.money), confidential NFTs, and shielded cross-chain bridges where both the asset and the transaction logic must be hidden. It provides a complete privacy stack.

Specific advantage: Provides high-level languages (Noir) and SDKs for building complex private applications. This matters for protocols requiring custom private logic, like confidential voting with weighted stakes or private on-chain gaming. It's a full-fledged development environment, not just a library.

Specific weakness: Operates as an app-specific zk-rollup, creating friction for cross-application composability. This matters for projects that require deep integration with the broader Ethereum DeFi ecosystem. Users and assets must bridge into Aztec's shielded environment, adding steps versus a native L1/L2 library like Semaphore.

Specific advantage: A lightweight ZK-SNARK-based protocol for identity and signaling. It's designed for group membership proofs and anonymous voting on-chain. This matters for applications like DAO governance (e.g., Unirep) or anonymous credentials where the privacy logic is simple and needs to be verifiable directly on a host chain like Ethereum or Polygon.

Specific limitation: Primarily a privacy primitive, not a full execution environment. It excels at proving membership and broadcasting signals but lacks native support for private smart contract state and complex private computations. This matters if you need to build a private DEX or a lending protocol with shielded balances; you'd have to build significant infrastructure around Semaphore.

Specific advantage: A zk-rollup with a privacy-first VM (Aztec VM) enabling fully private, programmable logic. Supports private state and private function execution via Noir. This matters for building complex, composable DeFi applications like zk.money (private swaps) or confidential NFT markets where both asset amounts and identities must be hidden.

Specific limitation: A newer, more complex stack with a steeper learning curve. While powerful, the ecosystem of audited contracts, developer tools, and integrations is smaller compared to established L1s. This matters for teams with tight deadlines or those requiring extensive third-party oracle/ bridge support, as they may face longer development cycles.

Specific advantage: Easy to integrate as a modular component into existing Ethereum dApps. Its gas-efficient proofs and straightforward API make it ideal for adding a single privacy feature (e.g., anonymous polling) without migrating your entire application. This matters for teams wanting incremental privacy without adopting a new L2 stack.

Specific limitation: Higher computational cost for proving complex private transactions, leading to higher fees and lower throughput compared to transparent rollups. Current TPS is limited by ZK proof generation times. This matters for high-frequency trading applications or mass-market social apps requiring sub-second, low-cost private transactions.