Series: Zero to Zero Knowledge
Today we take a look at Lelantus!
Released in 2019, this protocol builds upon Zerocoin. It is used in the Firo currency (formerly Zcoin) to enable private on-chain transactions. It resembles Zcash in some ways but is distinctly different in most aspects.
Similar to Zcash, Firo uses shielded addresses to achieve anonymous payments.
Timeline:
The Σ (Sigma) protocol used in earlier versions of Zcoin/Firo had a major limitation: users could only mint fixed denominations.
This created smaller anonymity sets and opened the door to timing attacks between mint and redeem operations (plus the "tainted change" problem).
Lelantus solves the fixed denomination issue by allowing mints from a single larger set.
Key benefits:
Limitation: Set size is currently capped at 65,000 coins.
A coin commitment is a double-blinded commitment encoding the coin serial number and the coin value.
These function similarly to Notes in Zcash.
The coin commitment is published and stored on the ledger when the coin is created (via Mint or Spend transactions).
Lelantus uses the classic basecoin < - > zerocoin model.
Important feature: Partial redemptions are now possible while keeping the remainder and amounts hidden.
Like Zcash, transparent transactions must be explicitly selected by the user.
Lelantus utilizes One-of-Many Proofs to extract input values necessary for proving balance without revealing the input origins - and without requiring a trusted setup.
These proofs are also used in Triptych (mentioned in our CryptoNote thread).
Firo nodes use the same Network Magic as Zcash's Magicbean.
Like Monero, Firo implemented Dandelion++ to add privacy by obfuscating the IP address of the transaction broadcaster.
Dandelion++ phases:
This makes it much harder to trace the origin of a transaction through network analysis.
Lelantus-Spark (planned for later 2023) introduces two levels of opt-in visibility using ZIP-32 style derivation and diversified addresses.
It will also add support for:
These features parallel Zcash Shielded Assets.
Original Thread by ZecHub (@ZecHub)
https://x.com/ZecHub/status/1641902859800150017
This page was compiled from the original Zero to Zero Knowledge thread for the ZecHub wiki.