> ## Documentation Index
> Fetch the complete documentation index at: https://docs.usenautilius.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Architecture

> Trace Nautilius from browser-encrypted offers through FCC result verification and FTestXRP escrow.

Nautilius separates public coordination from confidential price discovery.

<Note>
  The diagram uses `SilentLotInstructionSender` because that is the immutable name of the verified v0.1 Coston2 artifact.
</Note>

```text theme={null}
seller wallet
  ├─ register salted evidence commitments ────────────────→ LandDeal
  ├─ bind auction before encryption ─────────────────────→ SilentLotInstructionSender
  │                                                        └─ FlareTeeManager selects TEE
  └─ sign + ECIES-encrypt CREATE to bound TEE key ────────→ TeeExtensionRegistry

bidder wallet
  └─ EIP-712 sign + ECIES-encrypt offer ─→ server relay ─→ TeeExtensionRegistry
                                                          └─ same selected TEE
                                                              └─ /decrypt
                                                                  └─ TypeScript matcher

TEE/proxy ─ signed ActionResult ─→ browser/Go verifier ─→ LandDeal.consumeClearing
                                                        ├─ verify chain/domain/action/status
                                                        ├─ verify selected TEE signer and replay
                                                        └─ decode fixed clearing payload

selected buyer ─ FTestXRP approve/deposit ─→ LandDeal escrow
seller ─ consent + registry commitments ───→ pull credit ─→ seller
expired/failed completion ─────────────────→ pull refund ─→ buyer
```

## Components

`web/` hashes user-selected title evidence locally with 32 bytes of fresh salt, verifies deployment code and live state, binds the TEE before encryption, creates EIP-712 authorizations, encrypts with Go-Ethereum-compatible ECIES, submits transactions, polls signed FCC results and shows explorer receipts. `SILENTLOT_RELAYER_PRIVATE_KEY` is server-only; it is never included in the browser bundle.

`contracts/InstructionSender.sol` contains the v0.1 registered FCC instruction entry point. The parcel seller first calls `bindAuctionTee`; all CREATE/BID/CLEAR actions for that auction then use the same machine. Returned registry action IDs are recorded once and cannot overwrite existing bindings.

`typescript/` is the only Nautilius extension implementation. Ciphertext is passed to the TEE node `/decrypt` endpoint, then the plaintext is strictly decoded and validated. State is currently process-local: a TEE restart loses open auctions, so the present design needs operational continuity or a future sealed persistence mechanism.

`contracts/LandDeal.sol` stores commitments and lifecycle state, verifies the exact signed FCC result, and holds exact-transfer FTestXRP. It uses pull credits for seller settlement and buyer refunds.

`tools/` contains generated ABI bindings and Coston2 deployment/verification CLIs. It is not an alternate extension implementation.

## Fixed clearing schema

The extension ABI-encodes:

```solidity theme={null}
(bytes32 schema, bytes32 auctionId, bytes32 parcelCommitment,
 address seller, address selectedBuyer, uint256 clearingAmount,
 uint32 bidCount, uint64 closesAt, uint64 resultExpiresAt,
 bytes32 receiptCommitment)
```

`LandDeal` accepts it only when the schema, parcel, seller, close, action mapping, CLEAR command, expiry, selected TEE signature and replay guards all match.

## Failure behavior

* Missing deployment, extension, proxy or relay configuration disables the affected path; no fake success is shown.
* A rejected wallet request, reverted transaction or failed TEE result remains an explicit error.
* An unfunded clearing can be expired after its deadline.
* A funded deal that misses consent/completion deadline can expose a buyer pull refund.
* Failed outgoing token transfers preserve the corresponding credit because the transaction reverts atomically.

Continue with the [privacy and threat model](/concepts/privacy-and-threats) or inspect the [clearing-result schema](/reference/clearing-result).