Plonk vs Groth16 for Privacy Scaling

Universal trusted setup: A single, reusable ceremony (e.g., Perpetual Powers of Tau) supports all circuits, drastically simplifying deployment. This is critical for rapid protocol iteration and teams building multiple applications.

Supports custom gates: Enables more efficient arithmetic representations, optimizing for specific computations like hashing or signature verification.

Smallest proof size: ~200 bytes, leading to the lowest on-chain verification gas costs. This is non-negotiable for high-frequency, cost-sensitive applications on Ethereum L1.

Fastest verification time: Sub-second verification on-chain. Essential for protocols like Zcash and Tornado Cash where per-transaction efficiency is paramount.

Larger proof size: ~400-800 bytes, resulting in ~2-3x higher verification gas costs versus Groth16. This adds up for applications with thousands of daily proofs.

Prover time can be higher: While flexible, the generalized arithmetic can be less optimized than a hand-tuned Groth16 circuit for a specific task.

Per-circuit trusted setup: Each new circuit requires a new, secure multi-party ceremony. This creates operational overhead and risk for development teams.

Inflexible for updates: Any change to the circuit logic invalidates the setup, hindering agile development and bug fixes post-deployment.

Single trusted setup for all circuits. A one-time ceremony (like the Perpetual Powers of Tau) supports any future Plonk-based application. This drastically reduces operational overhead for teams deploying new privacy features, rollups (Aztec, zkSync), or custom logic.

Supports custom gates and recursion natively. Enables more efficient arithmetic and easier proof aggregation. This is critical for complex DeFi applications (e.g., AMMs with privacy) and layer-2 networks that need to bundle proofs, like Polygon zkEVM.

Smallest proofs (~200 bytes) and fastest on-chain verification. This results in the lowest possible gas costs for Ethereum L1 verification. The benchmark standard for applications where per-transaction cost is paramount, such as private token transfers (Tornado Cash classic).

Highly optimized over 5+ years with stable libraries (bellman, snarkjs). Offers predictable performance and extensive documentation. Ideal for teams with well-defined, static circuits who prioritize battle-tested reliability and don't anticipate frequent logic changes.

Proofs are ~1 KB (5x Groth16) with slower verification. This leads to higher gas costs for on-chain verification. A significant consideration for high-frequency, low-value transactions on Ethereum mainnet where gas dominates cost.

Requires a new trusted setup ceremony for each unique circuit. This creates ongoing operational security burdens and delays for protocol upgrades. A major drawback for agile teams iterating on product features or maintaining multiple circuit versions.

Specific advantage: ~10-20x faster prover times and smaller proof sizes (~200 bytes) compared to early Plonk implementations. This matters for high-frequency private transactions where latency is critical, as seen in Zcash's shielded transfers.

Specific advantage: Ultra-efficient on-chain verification (~200k gas on Ethereum). This matters for cost-sensitive L2 validity proofs and private DeFi where every unit of gas impacts user fees, making it the historical choice for early rollups.

Specific disadvantage: Requires a circuit-specific, perpetual trusted setup (MPC ceremony). This is a single point of failure for security and creates operational overhead for each new application, unlike Plonk's universal setup.

Specific disadvantage: No support for runtime circuit modifications. Any logic change (e.g., adding a new opcode) necessitates a completely new trusted setup. This matters for rapidly evolving protocols like general-purpose zkVMs (e.g., zkEVM), where Plonk's flexibility is superior.

Specific advantage: A single, reusable trusted setup (e.g., Perpetual Powers of Tau) supports any circuit up to a billion constraints. This matters for developer agility and long-term security, enabling projects like Aztec Network and Polygon zkEVM to iterate without new ceremonies.

Specific advantage: Plonkish arithmetization allows for tailored constraint systems (e.g., custom lookup arguments). This matters for optimizing complex circuits (like SHA-256 or ECDSA) found in zkEVMs and identity protocols, achieving better prover performance than vanilla Groth16.