using System; using System.IO; using System.Security.Cryptography; using System.Text; using System.Threading.Tasks;

​

class Program { // Giá trị pbLocal và pvLocal bạn đã cung cấp 

    private static readonly string pbLocal = "QY95kGY+IHN1fv/YZgGzZvR1Q5z8DoE2odZ8s+OepNITau2UfvkWo1nsMXBNTkrL9EVjkXYOZvczDdTAxsVIUmoHkdYzqNaiPjuDNphxzdOd/Az20ur/mz9wmUqZzzwZo2aeJtoZ3Nee6ut9Qi/RZF8FkesPtFZPcuL9v9QQ4ag=";

    private static readonly string pvLocal = "ZECixRpS1P4LICup7XAlq52pjvt8hpLgO25Q4TkRhFiXsOqKfv2HPKpuG6sKoNavaYu8wp+Xvvj3FkPOBw1VewILkfANr+28gOxV+omZUg4bsY+49Hl+BVlC/9Ls+8yQ4FRO9Lc0TdF9747bXl7Ug/WWKRjO4xhkittq8RraJNXXj+xM2AaTsxtSW6UBYSEFNQlkG9EEuyz3al/QyCAmS3aRyxlraYiv9p44lN3lPj4=";

​

// Hàm giả lập GetVaultSecretValue

private static Task<string> GetVaultSecretValue(string appCode, string key)

{

    if (key == "pbECCLocal")

        return Task.FromResult(pbLocal);

    if (key == "pvECCLocal")

        return Task.FromResult(pvLocal);

    throw new Exception("Invalid key");

}

​

// Hàm mã hóa AES-GCM

private static byte[] AesGcmEncrypt(byte[] key, byte[] plainText)

{

    using var aes = new AesGcm(key);

    var nonce = new byte[12];

    RandomNumberGenerator.Fill(nonce);

    var cipherText = new byte[plainText.Length];

    var tag = new byte[16];

​

    aes.Encrypt(nonce, plainText, cipherText, tag);

​

    using var ms = new MemoryStream();

    ms.Write(nonce, 0, nonce.Length);

    ms.Write(tag, 0, tag.Length);

    ms.Write(cipherText, 0, cipherText.Length);

​

    return ms.ToArray();

}

​

// Hàm giải mã AES-GCM

private static byte[] AesGcmDecrypt(byte[] key, byte[] cipherData)

{

    using var aes = new AesGcm(key);

    var nonce = cipherData[..12];

    var tag = cipherData[12..28];

    var cipherText = cipherData[28..];

    var plainText = new byte[cipherText.Length];

​

    aes.Decrypt(nonce, cipherText, tag, plainText);

    return plainText;

}

​

// Hàm mã hóa chuỗi

public static async Task<string> EncryptStringToStoring(string plainText)

{

    try

    {

        var receiverPublicKey = Convert.FromBase64String("QY95kGY+IHN1fv/YZgGzZvR1Q5z8DoE2odZ8s+OepNITau2UfvkWo1nsMXBNTkrL9EVjkXYOZvczDdTAxsVIUmoHkdYzqNaiPjuDNphxzdOd/Az20ur/mz9wmUqZzzwZo2aeJtoZ3Nee6ut9Qi/RZF8FkesPtFZPcuL9v9QQ4ag=");

        using var senderEcdh = ECDiffieHellman.Create(ECCurve.NamedCurves.nistP256);

        byte[] ephemeralPublicKey = senderEcdh.ExportSubjectPublicKeyInfo();

​

        using var receiverPublic = ECDiffieHellman.Create(ECCurve.NamedCurves.nistP256);

        receiverPublic.ImportSubjectPublicKeyInfo(receiverPublicKey, out _);

        byte[] aesKey = senderEcdh.DeriveKeyMaterial(receiverPublic.PublicKey);

​

        byte[] encryptedData = AesGcmEncrypt(aesKey, Encoding.UTF8.GetBytes(plainText));

​

        using var ms = new MemoryStream();

        await ms.WriteAsync(BitConverter.GetBytes(ephemeralPublicKey.Length), 0, 4);

        await ms.WriteAsync(ephemeralPublicKey, 0, ephemeralPublicKey.Length);

        await ms.WriteAsync(encryptedData, 0, encryptedData.Length);

        return Convert.ToBase64String(ms.ToArray());

    }

    catch (Exception ex)

    {

        throw new Exception("Sai khóa mã hóa hoặc dữ liệu trống: " + ex.Message);

    }

}

​

// Hàm giải mã chuỗi

public static async Task<string> DecryptStringToStoring(string encryptedText)

{

    try

    {

        var receiverPrivateKey = Convert.FromBase64String("ZECixRpS1P4LICup7XAlq52pjvt8hpLgO25Q4TkRhFiXsOqKfv2HPKpuG6sKoNavaYu8wp+Xvvj3FkPOBw1VewILkfANr+28gOxV+omZUg4bsY+49Hl+BVlC/9Ls+8yQ4FRO9Lc0TdF9747bXl7Ug/WWKRjO4xhkittq8RraJNXXj+xM2AaTsxtSW6UBYSEFNQlkG9EEuyz3al/QyCAmS3aRyxlraYiv9p44lN3lPj4=");

​

        using var receiverEcdh = ECDiffieHellman.Create(ECCurve.NamedCurves.nistP256);

        receiverEcdh.ImportECPrivateKey(receiverPrivateKey, out _);

​

        var encryptedData = Convert.FromBase64String(encryptedText);

        // Đọc độ dài ephemeral public key

        int ephemeralPublicKeyLength = BitConverter.ToInt32(encryptedData, 0);

        byte[] ephemeralPublicKey = new byte[ephemeralPublicKeyLength];

        Buffer.BlockCopy(encryptedData, 4, ephemeralPublicKey, 0, ephemeralPublicKeyLength);

​

        // Phần còn lại là dữ liệu mã hóa

        byte[] cipherText = new byte[encryptedData.Length - 4 - ephemeralPublicKeyLength];

        Buffer.BlockCopy(encryptedData, 4 + ephemeralPublicKeyLength, cipherText, 0, cipherText.Length);

​

        using var senderPublic = ECDiffieHellman.Create();

        senderPublic.ImportSubjectPublicKeyInfo(ephemeralPublicKey, out _);

        byte[] aesKey = receiverEcdh.DeriveKeyMaterial(senderPublic.PublicKey);

​

        byte[] decryptedData = AesGcmDecrypt(aesKey, cipherText);

        return Encoding.UTF8.GetString(decryptedData);

    }

    catch (Exception ex)

    {

        throw new Exception("Dữ liệu giải mã lỗi hoặc sai khóa giải mã hoặc dữ liệu trống: " + ex.Message);

    }

}

​

static async Task Main(string[] args)

{

    try

    {

        // Chuỗi đầu vào để mã hóa

        string plainText = "Hello, this is a test string!";

        Console.WriteLine("Chuỗi gốc: " + plainText);

​

        // Mã hóa chuỗi

        string encryptedText = await EncryptStringToStoring(plainText);

        Console.WriteLine("Chuỗi mã hóa: " + encryptedText);

​

        // Giải mã chuỗi

        string decryptedText = await DecryptStringToStoring(encryptedText);

        Console.WriteLine("Chuỗi giải mã: " + decryptedText);

​

        // Kiểm tra kết quả

        if (plainText == decryptedText)

        {

            Console.WriteLine("Mã hóa và giải mã thành công!");

        }

        else

        {

            Console.WriteLine("Mã hóa và giải mã thất bại!");

        }

    }

    catch (Exception ex)

    {

        Console.WriteLine("Lỗi: " + ex.Message);

    }

}}