Privacy Technology Comparison
How Firo's privacy technology compares to other privacy coins
Overview
This comprehensive guide examines major blockchain privacy mechanisms and demonstrates how Firo's Lelantus protocols compare to competitors. The fundamental challenge is balancing privacy with the public verifiability that blockchains require.
Major Privacy Mechanisms Analyzed
1. Cryptocurrency Tumblers & CoinJoin
Used in: Dash, Decred, Bitcoin Cash, Bitcoin mixers
Users mix funds by combining coins into a pool, then withdrawing equivalent amounts, obscuring original ownership.
Advantages
- • Works with most cryptocurrencies
- • Simple implementation
- • Regular transaction format
Critical Limitations
- • Transaction amounts visible
- • Low anonymity sets (typically 3)
- • Exchange freezing risk
- • Vulnerable to cluster attacks
Real-world issue: Some services may flag CoinJoin activity; policies and implementations vary, so verify current service rules.
2. CryptoNote & Ring Signatures (RingCT)
Used in: Monero, Particl, Zano
Ring signatures prove a transaction is signed by someone in a group without revealing identity. RingCT adds amount hiding.
Advantages
- • No trusted mixer required
- • Automatic mixing
- • Amounts hidden via RingCT
- • Mandatory stealth addressing
Documented limitations and research questions
- • Statistical-analysis risks documented in research
- • Limited ring size (11-16)
- • Vulnerable to flooding attacks
- • Quantum computing risk
Long-term cryptographic risks depend on future capabilities and protocol upgrades; retroactive deanonymization is not a certain outcome.
3. Lelantus v1/v2
Used in: Firo (activated January 2021)
Burn-and-redeem model using one-out-of-many proofs (Groth-Bootle proofs) requiring no trusted setup.
Key Features
- • Anonymity sets up to 65,000
- • Arbitrary burn/redemption amounts
- • Partial redemptions with hidden change
- • ~1.5 KB proof sizes
- • Batch verification efficiency
Advantages
- • Well-researched DDH cryptography
- • No trusted setup required
- • Simple UTXO handling
- • High anonymity sets
Limitations
- • Anonymity capped at high thousands
- • v1 doesn't fully hide amounts
- • No stealth addressing (v1)
4. Lelantus Spark
Currently active on Firo mainnet
Enhancement over Lelantus v1/v2 with broad privacy capabilities
New Capabilities
- ✓Full stealth address support via "Spark addresses"
- ✓One-time address generation for recipients
- ✓View key functionality for balance disclosure
- ✓Amount hiding with security proofs
Advantages
- • Retains all Lelantus benefits
- • Security proofs available
- • Modular architecture
- • Recipient-privacy design
Performance
- • Scaling to ~100,000 anonymity set
- • Batch verification optimization
- • Efficient multi-signatures
5. Zerocash (zkSNARKs)
Used in: Zcash, PirateChain, Horizen, Komodo, PIVX
Uses zkSNARKs (Zero-Knowledge Succinct Non-Interactive Arguments of Knowledge)
Theoretical Strengths
- • Global anonymity set
- • Small, fast-to-verify proofs
- • Amount hiding
- • No fixed denominations
Design tradeoffs and historical issues
- • Requires trusted setup ceremony
- • High computational burden
- • Multiple counterfeiting bugs found
- • High implementation and audit complexity
Critical vulnerabilities: Sprout mainnet contained counterfeiting bug for two years (launch until October 2018). BTCP suffered undetected hidden inflation for almost 10 months.
Complexity concern: Complex cryptographic systems require careful implementation, review and prompt security updates.
6. Mimblewimble
Used in: Grin, Beam, Litecoin MWEB sidechain, MimbleWimble Coin
Aggregates all transactions in a block into one massive transaction, hiding which inputs correspond to which outputs.
Advantages
- • All amounts hidden
- • Lightweight construction
- • Blockchain size reduction
- • Simple, understandable design
Network-layer research findings
- • High linkability reported in one 2019 test setup
- • Network monitoring vulnerability
- • No supply auditability
- • Low transaction volume issue
2019 Study: A 2019 network-layer study reported high linkability under its test conditions. That result should not be generalized to every current Mimblewimble deployment.
Summary Comparison
| Mechanism | Anonymity Set | Trusted Setup | Key Weakness |
|---|---|---|---|
| CoinJoin | 3-11 | No | Exchange freezing, low anonymity |
| RingCT | 11 (Monero) | No | Statistical deanonymization |
| Lelantus | 65,000 | No | Limited scaling |
| Lelantus Spark | 100,000 | No | Scaling limits |
| Zerocash | Global | Yes | Trusted setup, complexity |
| Mimblewimble | Variable | No | Network monitoring vulnerability |
Firo's Position
"Lelantus and Lelantus Spark compare very favorably to other anonymity schemes by providing a very well-rounded anonymity package, giving very strong anonymity using proven cryptography while remaining scalable."
Firo's approach prioritizes:
- • Standard, well-researched cryptographic assumptions
- • Absence of trusted setup requirements
- • Simpler constructions reducing implementation risks
- • Practical anonymity sets exceeding mixer-based systems
- • Optional supply auditability