// 1. 準(zhǔn)備數(shù)據(jù)
const text = "123456";
const encoder = new TextEncoder();
const data = encoder.encode(text);

// 2. 計算哈希
const hashBuffer = await crypto.subtle.digest('SHA-256', data);

// 3. 轉(zhuǎn)為十六進(jìn)制
const hashArray = Array.from(new Uint8Array(hashBuffer));
const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join('');

console.log("SHA-256:", hashHex);
// 輸出: 8d969eef6ecad3c29a3a629280e686cf0c3f5d5a86aff3ca12020c923adc6c92

// 最簡單的AES加密解密
async function aesSimple() {
  // 1. 生成密鑰
  const key = await crypto.subtle.generateKey(
    {name: "AES-GCM", length: 256}, true, ["encrypt", "decrypt"]
  );
  
  // 2. 加密
  const iv = crypto.getRandomValues(new Uint8Array(12));
  const encrypted = await crypto.subtle.encrypt(
    {name: "AES-GCM", iv}, key, new TextEncoder().encode("你好世界")
  );
  
  // 3. 解密
  const decrypted = await crypto.subtle.decrypt(
    {name: "AES-GCM", iv}, key, encrypted
  );
  
  console.log("結(jié)果:", new TextDecoder().decode(decrypted)); // 你好世界
}
aesSimple();

// ECC 密鑰交換完整流程演示
class ECCFlow {
  static async demonstrateCompleteFlow() {
    console.log("ECC 密鑰交換完整流程演示");
    console.log("==========================");
    
    // 第1步：選擇橢圓曲線
    console.log("\n第1步：選擇橢圓曲線");
    const curve = "P-256";
    console.log("   選擇的曲線: " + curve);
    console.log("   安全強(qiáng)度: 128位");
    console.log("   公鑰長度: 65字節(jié)");
    console.log("   私鑰長度: 32字節(jié)");
    
    // 第2步：雙方生成密鑰對
    console.log("\n第2步：雙方生成密鑰對");
    
    // Alice 生成密鑰對
    const aliceKeyPair = await crypto.subtle.generateKey(
      { name: "ECDH", namedCurve: curve },
      true,
      ["deriveKey"]
    );
    console.log("   Alice 生成密鑰對:");
    console.log("     - 私鑰: 保密存儲");
    console.log("     - 公鑰: 準(zhǔn)備發(fā)送給 Bob");
    
    // Bob 生成密鑰對
    const bobKeyPair = await crypto.subtle.generateKey(
      { name: "ECDH", namedCurve: curve },
      true,
      ["deriveKey"]
    );
    console.log("   Bob 生成密鑰對:");
    console.log("     - 私鑰: 保密存儲");
    console.log("     - 公鑰: 準(zhǔn)備發(fā)送給 Alice");
    
    // 第3步：交換公鑰
    console.log("\n第3步：交換公鑰（通過網(wǎng)絡(luò)）");
    
    const bobPublicKey = bobKeyPair.publicKey;
    console.log("   Alice 收到 Bob 的公鑰");
    
    const alicePublicKey = aliceKeyPair.publicKey;
    console.log("   Bob 收到 Alice 的公鑰");
    
    // 第4步：計算共享密鑰
    console.log("\n第4步：各自計算共享密鑰");
    console.log("   數(shù)學(xué)原理:");
    console.log("   Alice私鑰 × Bob公鑰 = Bob私鑰 × Alice公鑰");
    
    // Alice 計算共享密鑰
    const aliceSharedKey = await crypto.subtle.deriveKey(
      {
        name: "ECDH",
        public: bobPublicKey
      },
      aliceKeyPair.privateKey,
      { name: "AES-GCM", length: 256 },
      true,
      ["encrypt", "decrypt"]
    );
    console.log("   Alice 計算共享密鑰完成");
    
    // Bob 計算共享密鑰
    const bobSharedKey = await crypto.subtle.deriveKey(
      {
        name: "ECDH",
        public: alicePublicKey
      },
      bobKeyPair.privateKey,
      { name: "AES-GCM", length: 256 },
      true,
      ["encrypt", "decrypt"]
    );
    console.log("   Bob 計算共享密鑰完成");
    
    // 第5步：驗(yàn)證密鑰相同
    console.log("\n第5步：驗(yàn)證雙方密鑰相同");
    
    const aliceKeyBytes = await crypto.subtle.exportKey("raw", aliceSharedKey);
    const bobKeyBytes = await crypto.subtle.exportKey("raw", bobSharedKey);
    
    const aliceHex = Array.from(new Uint8Array(aliceKeyBytes))
      .map(b => b.toString(16).padStart(2, '0'))
      .join('');
    
    const bobHex = Array.from(new Uint8Array(bobKeyBytes))
      .map(b => b.toString(16).padStart(2, '0'))
      .join('');
    
    console.log("   驗(yàn)證結(jié)果:");
    console.log("   Alice 密鑰: " + aliceHex.substring(0, 32) + "...");
    console.log("   Bob 密鑰:   " + bobHex.substring(0, 32) + "...");
    console.log("   是否相同: " + (aliceHex === bobHex ? "是" : "否"));
    
    // 第6步：使用共享密鑰加密通信
    console.log("\n第6步：使用共享密鑰加密通信");
    
    const message = "會議時間改為下午2點(diǎn)";
    console.log("   Alice 要發(fā)送: \"" + message + "\"");
    
    // 加密
    const iv = crypto.getRandomValues(new Uint8Array(12));
    const encrypted = await crypto.subtle.encrypt(
      { name: "AES-GCM", iv },
      aliceSharedKey,
      new TextEncoder().encode(message)
    );
    
    console.log("   加密完成:");
    console.log("     - 密文長度: " + encrypted.byteLength + " 字節(jié)");
    console.log("     - IV: " + Array.from(iv).slice(0, 3).join(',') + "...");
    
    // 第7步：Bob 解密消息
    console.log("\n第7步：Bob 解密消息");
    
    const decrypted = await crypto.subtle.decrypt(
      { name: "AES-GCM", iv },
      bobSharedKey,
      encrypted
    );
    
    const decryptedMessage = new TextDecoder().decode(decrypted);
    console.log("   Bob 解密得到: \"" + decryptedMessage + "\"");
    console.log("   是否正確: " + (message === decryptedMessage ? "是" : "否"));
    
    // 安全性分析
    console.log("\n安全性分析:");
    console.log("   中間人無法計算共享密鑰");
    console.log("   即使竊聽到公鑰交換也沒用");
    console.log("   每次會話可生成新的密鑰對");
    
    return {
      aliceKeyPair,
      bobKeyPair,
      sharedKey: aliceSharedKey,
      encryptedMessage: encrypted
    };
  }
}

// 運(yùn)行完整流程
ECCFlow.demonstrateCompleteFlow().catch(console.error);