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zkTelos Pool Contract

The zkTelos Pool is the core smart contract of the protocol. It receives transactions from the relayer (or directly from users), verifies ZK proofs, and updates the on-chain shielded state.

Contract Addresses​

See Deployed Contracts for all pool and verifier addresses on Telos EVM.

Pool Initialization​

Each pool serves a single token and has a unique pool_id — an unsigned 24-bit integer.

constructor(
    uint256 __pool_id,
    address _token,
    ITransferVerifier _transfer_verifier,
    ITreeVerifier _tree_verifier
)
PoolTokenPool ID
WTLOS Pool0xD102cE6A4dB07D247fcc28F366A623Df0938CA9E40001
USDC.e Pool0xF1815bd50389c46847f0Bda824eC8da914045D1440002

Denominators​

Two denominators are used when translating between user-facing amounts and on-chain values:

uint256 constant TOKEN_DENOMINATOR = 1 gwei;   // 1e9
uint256 constant NATIVE_DENOMINATOR = 1 gwei;  // 1e9

When a user specifies an amount (e.g., 5 tokens), the pool multiplies by TOKEN_DENOMINATOR to get the actual token value in wei. This is also used to calculate deposit/withdrawal limits.

Merkle Tree Root​

The pool maintains a Merkle tree of height 48. The initial root for an empty tree (all leaves zero) is:

11469701942666298368112882412133877458305516134926649826543144744382391691533

Transaction Processing​

All transactions are processed via the transact() method:

function transact() external payable onlyOperator;

All transaction data is passed through calldata. Before processing, the ZK proofs are verified by the Verifier contracts. The onlyOperator modifier ensures only authorized relayers can submit transactions.

Transaction types supported:

  • Deposit (type 0) — move tokens into the shielded pool
  • Transfer (type 1) — private transfer within the pool
  • Withdrawal (type 2) — move tokens out of the pool
  • Permittable deposit (type 3) — deposit using EIP-2612 permit signature

Limits​

The pool supports configurable limits to prevent large-scale transactions:

function setLimits(
    uint256 _tvlCap,            // max total value locked
    uint256 _dailyDepositCap,   // max deposits per day
    uint256 _dailyWithdrawalCap,// max withdrawals per day
    uint256 _dailyUserDepositCap,// max per-user deposits per day
    uint256 _depositCap         // max single deposit
)

Source Code​

The pool contract is based on ZkBobPool.sol from the zkBob contracts repository.