# Wallet

The **Wallet** is a standalone Command Line Interface (CLI) tool that acts as the primary interface for users to interact with the pETHit blockchain. It implements the "Client-Side Signing" paradigm, ensuring that private keys never leave the user's machine.

## Current Architecture (v0.3.0)

This is a newly introduced component in Iteration 3. It serves three main purposes: **Identity Management**, **Transaction Signing**, and **Network Communication**.

### 1. Identity Management (Key Generation)

The wallet generates and manages cryptographic identities using the **ECDSA** (Elliptic Curve Digital Signature Algorithm) on the `secp256k1` curve, the same standard used by Ethereum.

* **Private Key:** A random 32-byte number generated via `rand::OsRng`.
* **Public Key:** Derived from the private key.
* **Address:** The last 20 bytes of the Keccak256 hash of the public key (Ethereum standard).

### 2. Transaction Signing

The wallet constructs and signs transactions locally before broadcasting them.

1. **Nonce Fetching:** It queries the Node (`/get_account`) to find the next valid nonce for the address.
3. **Hashing:** It calculates the Keccak256 hash of the transaction before signing.
4. **Signing:** It signs the hash using the private key to produce a signature (`r`, `s`, `v`).
2. **RLP Encoding:** It creates the signed transaction and encodes it into an RLP byte stream.

### 3. Network Communication

The wallet acts as a JSON-RPC client. It uses `reqwest` to send HTTP POST requests to the Node.

* **Querying:** Uses `POST /get_account` to read state.
* **Broadcasting:** Uses `POST /send_tx` to submit signed transactions (as Hex strings).

## API / Usage

The Wallet is a binary executable (`pethit-wallet`).

### Commands

#### `generate`

Creates a new random wallet identity.

* **Output:** Prints the Private Key and the derived Address.

cargo run -p pethit-wallet -- generate

#### `send`

Constructs, signs, and sends a transaction.

* **Arguments:**
* `--private-key`: The hex string of the signer's key.
* `--to`: The destination address.
* `--value`: The amount to send (in Wei).
* `--rpc`: (Optional) The URL of the pETHit node (Default: `http://127.0.0.1:3000`).

cargo run -p pethit-wallet -- send \
  --private-key <YOUR_KEY> \
  --to 0x... \
  --value 100 \
  --rpc http://127.0.0.1:3000

## Evolution Log

### v0.3.0: The Client

* **Creation:** Initial release of the `pethit-wallet` crate.
* **Features:** Key generation, local signing (ECDSA), RLP serialization, and RPC integration.
* **Role:** Replaced manual `curl` commands, enabling secure and strictly typed interactions with the blockchain.