Lelantus Spark
Firo's next-generation privacy protocol that hides sender, receiver, and amount — with no trusted setup required.
From Zerocoin to Spark
Firo's privacy technology has evolved through several generations, each addressing the limitations of the previous:
Zerocoin
First practical implementation. Required trusted setup and only supported fixed denominations. Provided basic privacy through zero-knowledge proofs.
Sigma
Removed the trusted setup requirement while keeping fixed denominations. Smaller proof sizes and improved efficiency.
Lelantus
Introduced flexible amounts (no fixed denominations), larger anonymity sets, and one-out-of-many proofs. No trusted setup.
Lelantus Spark
Full privacy: hidden amounts, Spark addresses, direct private transfers, and view keys. The most complete privacy solution yet.
Key Features of Spark
Confidential Amounts
Transaction amounts are cryptographically hidden using Pedersen commitments and range proofs. Nobody can see how much you sent or received.
Spark Addresses
A new address type (starting with "sm1...") that can be publicly shared for receiving funds, while all incoming transactions are automatically private.
Direct Private Transfers
No need for separate burn-and-redeem steps. Send coins directly from one Spark address to another in a single private transaction.
No Trusted Setup
All cryptographic proofs are based on well-studied discrete logarithm assumptions. No multi-party ceremony, no trust required.
Efficient Proofs
Spark uses optimized proof constructions that keep transaction sizes manageable while providing strong privacy guarantees.
View Keys
Optional incoming view keys let you grant read-only access to your transaction history — useful for auditing or compliance without surrendering control.
How Spark Works
When you send FIRO using Spark, the following happens under the hood:
- Coin serialization: Your coins are "burned" (removed from the transparent pool) and added to the global Spark anonymity set.
- Proof generation: A zero-knowledge proof is created that proves you own sufficient funds to make the transaction, without revealing which specific coins are yours.
- Amount hiding: The transfer amount is encrypted using Pedersen commitments. Only the sender and receiver can determine the amount.
- Coin creation: New Spark coins are created for the receiver at their Spark address. These coins have no history — they appear to come from the entire anonymity set.
- Verification: Network nodes verify the proof's validity without learning anything about the sender, receiver, or amount.
Anonymity Set Size
Spark's global anonymity set encompasses all coins that have ever been burned/anonymized. With 65,000+ coins in the set, the probability of linking any specific transaction to a sender is astronomically low — far higher privacy than ring signature approaches that use 11–16 decoys.
What's Next: Curve Trees
The next major upgrade to Spark is the integration of Curve Trees, an innovative technique for efficient membership proofs. With Curve Trees:
- The anonymity set becomes truly global — encompassing every Spark coin ever created
- Proof sizes remain small and verification stays fast, even as the set grows
- Privacy and scalability improve simultaneously — a rare achievement in cryptography
Curve Trees are on Firo's mid-term roadmap and represent a significant leap forward for blockchain privacy technology.
Try Spark Today
Download a Firo wallet and experience Lelantus Spark privacy firsthand.