new commit

client/package.json

@@ -9,7 +9,10 @@
     "preview": "vite preview"
   },
   "dependencies": {
-    "axios": "^0.27.2",
+    "axios": "^1.7.2",
+    "ethereum-cryptography": "^2.1.3",
+    "ethereumjs-tx": "^2.1.2",
+    "ethereumjs-util": "^7.1.5",
     "react": "^18.2.0",
     "react-dom": "^18.2.0"
   },

client/src/App.jsx

@@ -1,8 +1,10 @@
 import Wallet from "./Wallet";
-import Transfer from "./Transfer";
+// import Transfer from "./Transfer";
 import "./App.scss";
+import Transfer from "./Transffer";
 import { useState } from "react";
 
+
 function App() {
   const [balance, setBalance] = useState(0);
   const [address, setAddress] = useState("");

client/src/App.scss

@@ -83,4 +83,14 @@ input {
 .transfer {
   display: flex;
   flex-direction: column;
+
+  .signature {
+    letter-spacing: 1px;
+    font-weight: 400;
+    font-size: .9em;
+    display: inline-flex;
+    margin-top: 10px;
+    padding: 0.75rem;
+    background-color: #f4f6f8;
+  }
 }

client/src/Transfer.jsx

@@ -47,8 +47,10 @@ function Transfer({ address, setBalance }) {
       </label>
 
       <input type="submit" className="button" value="Transfer" />
+      <div className="signature">Mssg:</div>
     </form>
   );
 }
 
 export default Transfer;
+// new

client/src/Transffer.jsx

@@ -0,0 +1,69 @@
+import { useState } from "react";
+import server from "./server";
+
+function Transfer({ address, setBalance }) {
+  const [sendAmount, setSendAmount] = useState("");
+  const [recipient, setRecipient] = useState("");
+  // Dummy signature for demonstration purposes
+  const [dummySignature, setDummySignature] = useState("");
+
+  const setValue = (setter) => (evt) => setter(evt.target.value);
+
+  async function transfer(evt) {
+    evt.preventDefault();
+
+    try {
+      // Simulated transaction data
+      const transactionData = `${address}${recipient}${sendAmount}`;
+
+      // Generate a dummy signature (replace this with actual signature generation)
+      const dummySignatureValue = "0x1234567890123456789012345678901234567890"; // Replace with actual signature
+
+      const {
+        data: { balance },
+      } = await server.post(`send`, {
+        sender: address,
+        amount: parseInt(sendAmount),
+        recipient,
+        signature: dummySignatureValue, // Include the dummy signature in the request
+      });
+
+      setBalance(balance);
+    } catch (ex) {
+      alert(ex.response.data.message);
+    }
+  }
+
+  return (
+    <form className="container transfer" onSubmit={transfer}>
+      <h1>Send Transaction</h1>
+
+      <label>
+        Send Amount
+        <input
+          placeholder="1, 2, 3..."
+          value={sendAmount}
+          onChange={setValue(setSendAmount)}
+        ></input>
+      </label>
+
+      <label>
+        Recipient
+        <input
+          placeholder="Type an address, for example: 0x2"
+          value={recipient}
+          onChange={setValue(setRecipient)}
+        ></input>
+      </label>
+
+      {/* Display the dummy signature */}
+      <div className="signature">
+        Signature: <span>{dummySignature}</span>
+      </div>
+
+      <input type="submit" className="button" value="Transfer" />
+    </form>
+  );
+}
+
+export default Transfer;

server/index.js

@@ -7,9 +7,9 @@ app.use(cors());
 app.use(express.json());
 
 const balances = {
-  "0x1": 100,
-  "0x2": 50,
-  "0x3": 75,
+  "089b40fad730c2e6edc3": 100,
+  "9b7fcd1c1787f635d8a6": 50,
+  "cb062d401405b8ea555c": 75,
 };
 
 app.get("/balance/:address", (req, res) => {
@@ -42,3 +42,4 @@ function setInitialBalance(address) {
     balances[address] = 0;
   }
 }
+/// new

server/newIndex.js

@@ -0,0 +1,59 @@
+const express = require("express");
+const app = express();
+const cors = require("cors");
+const port = 3042;
+const { Transaction, utils } = require("ethereumjs-tx");
+
+app.use(cors());
+app.use(express.json());
+
+const balances = {
+  "089b40fad730c2e6edc3": 100,
+  "9b7fcd1c1787f635d8a6": 50,
+  "cb062d401405b8ea555c": 75,
+};
+
+// Function to verify a signature
+function verifySignature(messageHash, signature, publicKey) {
+  return Transaction.verifyTransaction(messageHash, signature, publicKey);
+}
+
+app.get("/balance/:address", (req, res) => {
+  const { address } = req.params;
+  const balance = balances[address] || 0;
+  res.send({ balance });
+});
+
+app.post("/send", (req, res) => {
+  const { sender, recipient, amount, signature } = req.body;
+
+  // Verify the signature
+  const messageHash = utils.sha3(utils.toBuffer(`${sender}${recipient}${amount}`));
+  const isValid = verifySignature(messageHash, signature, sender);
+
+  if (!isValid) {
+    res.status(403).send({ message: "Invalid signature" });
+    return;
+  }
+
+  setInitialBalance(sender);
+  setInitialBalance(recipient);
+
+  if (balances[sender] < amount) {
+    res.status(400).send({ message: "Not enough funds!" });
+  } else {
+    balances[sender] -= amount;
+    balances[recipient] += amount;
+    res.send({ balance: balances[sender] });
+  }
+});
+
+app.listen(port, () => {
+  console.log(`Listening on port ${port}`);
+});
+
+function setInitialBalance(address) {
+  if (!balances[address]) {
+    balances[address] = 0;
+  }
+}