# Lethe

> Lethe is a privacy protocol for managing crypto assets on Elysium (mainnet chain ID 99901, testnet 99801). Users shield supported tokens (HYPE, as wrapped HYPE, and one bridged stablecoin at launch) into a shared pool, move them privately inside it, and later withdraw them. Transfers inside the pool are private: the chain shows no sender, recipient or amount for them. Deposits and withdrawals are public on the chain, like any token transfer. Privacy grows with the pool.

## Status

Lethe's HYPE pool is live on Elysium Testnet (chain ID 99801) with test tokens of no value. Nothing is deployed on Elysium mainnet, and no LETHE token has launched. The app at /app/ works on Elysium Testnet with a browser wallet (shield, private send and withdraw test HYPE); it also offers a demo wallet with simulated balances. The testnet pool is 0x73b8be1ec39b0bc892b00291e3a024e04f97dd54. The contracts have not had an external security review.

Any token called LETHE, and any "Lethe pool" address, that is not listed on https://enterlethe.xyz/docs/contracts/ is not from this project.

## Design

- One pool contract holds every supported token. Every user action is one call to transact(proof, extData): a positive extAmount is a shield, zero is a private transfer, a negative extAmount is a withdrawal.
- Ownership is a set of encrypted notes. The chain stores commitments in a 20-level Poseidon Merkle tree; spending reveals nullifiers, which prevent double spends. Proofs are Groth16 on BN254 and are built in the user's browser.
- Each proof is bound to its outputs, its fee, its token, the chain ID, the pool address and an expiry.
- Keys are created on the user's device from fresh randomness and backed up with a 24-word recovery phrase. Nobody, including Lethe, can recover them.
- The admin will be a multisig that can only turn deposits of a token on or off. It cannot move funds, block withdrawals, change the verifier or upgrade the pool.
- Lethe never lends or deploys user deposits. There is no yield.

## Privacy limits

- Deposits and withdrawals are public: address, asset, amount and time.
- The more transactions the pool has, the larger its anonymity set. Common amounts and time between a deposit and a withdrawal help.
- A relayer sees the IP address and the transaction it submits. Elysium's sequencer orders every transaction and can delay or censor during its single-sequencer phase.

## Pages

- Home: https://enterlethe.xyz/
- How it works: https://enterlethe.xyz/how-it-works/
- Docs: https://enterlethe.xyz/docs/
- Project status: https://enterlethe.xyz/docs/project-status/
- Network and contracts: https://enterlethe.xyz/docs/contracts/
- What stays private: https://enterlethe.xyz/docs/privacy/
- Security: https://enterlethe.xyz/security/
- Whitepaper: https://enterlethe.xyz/docs/whitepaper/
- App (demo): https://enterlethe.xyz/app/