Mimblewimble (Grin/Beam) vs Zcash: Compact Blockchain vs Full Privacy Features

Radical blockchain pruning: Transactions are merged and old data is cut off, leading to a chain that grows at ~1/10th the rate of Bitcoin. This results in lower node storage costs and faster sync times. This matters for lightweight clients and long-term network scalability.

All transactions are private by default using confidential transactions and CoinJoin. There is no transparent ledger, making all coins inherently equal and untraceable. This matters for protocols where base-layer fungibility is the primary privacy goal, not selective disclosure.

Selective disclosure with zk-SNARKs: Users can choose between transparent (t-addr) and shielded (z-addr) transactions. Shielded pools offer full cryptographic privacy, while enabling compliance proofs via view keys. This matters for institutions and applications requiring auditability alongside privacy.

Established developer platform: Supports complex smart contracts via cross-chain bridges (e.g., Zcash on Ethereum via zkSNARKs verifiers) and wallets like ZecWallet. The Zcash Foundation and ECC provide formal audits and protocol upgrades (e.g., Halo 2). This matters for building privacy-preserving DeFi or identity applications.

Key advantage: Compact blockchain size via cut-through and CoinJoin. Transactions are aggregated, removing intermediate data. This results in a chain that grows ~10x slower than Bitcoin's. This matters for light clients and node operators who require lower storage and bandwidth costs, enabling broader decentralization.

Key advantage: Mandatory privacy for all transactions. Every transaction is confidential by default, ensuring strong fungibility. However, the protocol allows for selective auditability via view keys, which is critical for regulatory compliance and institutional use cases where proving solvency without revealing details is required.

Key advantage: Full privacy suite with selective disclosure. Users can choose between transparent (t-addr) and shielded (z-addr) transactions. Advanced features like memo fields and multi-asset shielding (via ZSA) are possible. This matters for complex DeFi applications and enterprises needing flexible, auditable private transactions.

Key advantage: Established developer tools and integrations. Zcash benefits from a ~$90M+ ecosystem fund and integrations with major wallets (Coinbase, Exodus) and explorers (Zchain). The EVM-compatible Zcash (via ECC's work) expands possibilities. This matters for protocols seeking a battle-tested privacy base with existing user and developer mindshare.

Key trade-off: No Turing-complete smart contracts. The design intentionally omits complex scripting to preserve privacy and scalability. This is a disadvantage for developers building private DeFi, NFTs, or complex dApps that require on-chain logic beyond simple value transfer.

Key trade-off: Cryptographic complexity and perceived trust. The original 2016 Powers of Tau ceremony involved a trusted setup, though the 2022 Halo 2 upgrade removed this requirement for future proofs. The dual-address system can also lead to user error and privacy leakage if used incorrectly, complicating the user experience.

Selective transparency with zk-SNARKs: Enables fully shielded transactions (z-addresses) where sender, receiver, and amount are cryptographically hidden. This is critical for regulatory compliance (like Zcash's use by Gemini) and applications requiring maximum anonymity, such as confidential DeFi or private donations.

Aggregation and cut-through: Transactions are merged and intermediate data is discarded, leading to a dramatically smaller blockchain. Grin's blockchain is ~90% smaller than Bitcoin's for the same number of transactions. This is optimal for light clients, faster sync times, and long-term scalability.

Inherent privacy by default: All transactions are confidential (amounts and addresses hidden) using Pedersen Commitments and CoinJoin. This provides strong fungibility—every coin is identical. The lean protocol design also enables lower fees (Beam avg. fee < $0.01) and is ideal for high-volume, private P2P payments.

Reliance on a cryptographic ceremony: Original zk-SNARKs required a trusted setup (though Halo 2 removes this). The protocol complexity also leads to higher computational requirements for shielded transactions (~40 sec generation time, ~1.5 MB proof size). This can be a barrier for lightweight integration.

Designed for simplicity, not extensibility: Lacks native smart contract support and complex scripting. Privacy is limited to basic transaction confidentiality; it cannot easily support private DeFi, NFTs, or identity schemes. Choose this for payments, not for a dApp platform.