zk Privacy Solution Comparison

zkBob | zk.money | Railgun | Tornado.cash |

How does zkBob compare to other privacy protocols?

zkBob provides everyday privacy to everyday users. Limits, compliant wallet checks, and other security features ensure that zkBob is a safe place for honest users to discreetly transfer stable value.

Different privacy solutions offer different tradeoffs for users seeking anonymity on-chain. Below are some features that set zkBob apart.

	zkBob	Railgun	Secret Network	zk.Money (sunset & no longer active)	Tornado.cash (pre-ban)
Stable fees	✅ $0.10/tx on Polygon $ dynamic stable fees on Optimism	❌ variable	❌ variable	❌ variable	❌ variable
Optional KYC	✅ users can submit KYC to increase deposit limits.	❌ No KYC option for individuals	❌ No KYC option for individuals	❌ N/A	❌ N/A
No additional wallet required	✅ standalone transfers and withdrawals from app	❌ requires wallet	❌ requires wallet	❌ requires wallet	❌ requires wallet
No native tokens required	✅ Tokens used for all interactions and pay for gas fees	❌ required for shielding	❌ SCRT required for fees	❌ required for withdrawal and deposit	❌ required for withdrawal/deposit
Multisender	✅ read more	❌	❌	❌	❌
Deposit limits (non-KYC)	✅ < 10K USDC per address in 24 hours, 300K total protocol per 24 hours	❌	❌	❌ N/A	❌
Tiered deposit limits (KYC'd)	✅ < 20K USDC per address in 24 hours.	❌	❌	❌	❌
Current withdrawal limits	✅ < 300K per day for the total protocol	❌	❌	❌	❌
Current pool size limits	✅ 2M USDC Polygon 10M USDC Optimism	❌	❌	❌	❌
TRM compliance integration	✅ Risk management and illicit funds detection	❌	❌	❌	❌
Cloud API	✅ Beta Gated implementation	❌	❌	❌	❌

A big differentiator between the protocols is zkBob’s use of tokens such as USDC for transactions and fees. With stable pools, transaction fees do not fluctuate for users (hard coded to $0.10 per tx on Polygon/ $0.50 per tx on Optimism). If the actual tx cost is less, the extra amount is collected and dedicated to protocol and user support. In rare cases when it costs more, txs are divided and processed in several transactions.

zkBob pools have the additional utility including the ability to introduce compounding and lost/expired token redistribution. These features on the roadmap will provide future incentives for zkBob users.

Multitransfer is another unique zkBob feature, allowing users to transfer to multiple zk addresses with a single transaction. This is especially useful for employers sending salary payments to many employees. Rather than create proofs and pay fees for each tx, these can be sent in bulk, saving time and overhead costs.

Additional zkBob roadmap items include multi-chain deployment, decentralized relayer infrastructure, and fast client state sync also set it apart from competitors in the space.

In the table below we explore some technical and operational differences between zkBob, zk.money and Tornado.cash (pre-ban).

Operational Comparison Table

Note comparisons were made to show varying technology and zk tech. As zk.money and tornado.cash are no longer in active operation (sunset or banned), zkBob is currently the primary solution for optional privacy.

	zkBob	zk.money (now sunset)	Tornado.cash (pre-ban)
Deployment Chain	Polygon	Aztec Network Rollup	Ethereum/Gnosis Chain
zkSNARK	Groth’16	PLONK	Groth’16
Verification time	~3 ms	~ 6ms	~3 ms
Prover algorithm RAM requirements	~5MB	~900MB	~10MB
Trusted setup	✅ Per circuit	✅ Universal	✅ Per circuit
Deposit gas size	642K	51K	910K
Arbitrary Deposits/Transfers/Withdrawals?	✅	✅	❌ Regular TC ✅ TC Nova
Gas fee token(s)	-> USDC/ETH/BOB deposits & withdrawals (no native token required)	-> ETH deposits & withdrawals	-> ETH deposits & withdrawals
Transfer token(s)	USDC, ETH, BOB	zkETH / zkDAI / zkrenBTC	ETH, DAI, USDC
Transaction times	< 1 minute, Polygon infra	Variable (4hours to < 5 min) based on desired fee	< 1 minute, Nova on Gnosis Chain infra
Tokenomics	✅ XP Auctions on roadmap	❌	✅ TORN governance token
Geo restrictions	✅ implemented	❌	❌
Multi-chain deployment	✅ Optimism & Polygon	❌	✅ (prior roadmap)
Decentralized relayers	✅ On roadmap	❌ (Multi-rollup infra on Roadmap)	✅
Fast client-state sync	✅ On roadmap	❌	❌