TripleDes problem in .Net

Question

I use TripleDes to encrypt/decrypt. I have a program in the .Net Framework version and in the .Net version.

According to the code I show, in .NetFw it returns an object "System.Security.Cryptography.CryptoAPITransform" to TDes_ICryptoTransform and for .Net it returns an object "System.Security.Cryptography.UniversalCryptoDecryptor".

It seems that "System.Security.Cryptography.CryptoAPITransform" is not supported in .Net and when trying to decode a string encoded in .NetFw in .Net, the results are different.

How can I get "System.Security.Cryptography.CryptoAPITransform" to return in .Net or to always generate "System.Security.Cryptography.UniversalCryptoDecryptor" in both .NetFw and .Net?

in both systems, TDes_TripleDESCryptoServiceProvider is an object "System.Security.Cryptography.TripleDESCryptoServiceProvider".

System.Security.Cryptography.ICryptoTransform TDes_ICryptoTransform = TDes_TripleDESCryptoServiceProvider.CreateEncryptor(key, iv);

Answer 1

Hi @zequion , Welcome to Microsoft Q&A,

Use the TripleDESCryptoServiceProvider class to ensure that the same encryption and decryption logic is used on .NET Framework and .NET Core, avoiding issues caused by platform differences.

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

public class TripleDESEncryption
{
    public static byte[] Encrypt(byte[] data, byte[] key, byte[] iv)
    {
        using (TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider())
        {
            tdes.Key = key;
            tdes.IV = iv;
            tdes.Mode = CipherMode.CBC;
            tdes.Padding = PaddingMode.PKCS7;

            using (ICryptoTransform encryptor = tdes.CreateEncryptor())
            {
                return PerformCryptography(data, encryptor);
            }
        }
    }

    public static byte[] Decrypt(byte[] data, byte[] key, byte[] iv)
    {
        using (TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider())
        {
            tdes.Key = key;
            tdes.IV = iv;
            tdes.Mode = CipherMode.CBC;
            tdes.Padding = PaddingMode.PKCS7;

            using (ICryptoTransform decryptor = tdes.CreateDecryptor())
            {
                return PerformCryptography(data, decryptor);
            }
        }
    }

    private static byte[] PerformCryptography(byte[] data, ICryptoTransform cryptoTransform)
    {
        using (MemoryStream memoryStream = new MemoryStream())
        {
            using (CryptoStream cryptoStream = new CryptoStream(memoryStream, cryptoTransform, CryptoStreamMode.Write))
            {
                cryptoStream.Write(data, 0, data.Length);
                cryptoStream.FlushFinalBlock();
                return memoryStream.ToArray();
            }
        }
    }
}

class Program
{
    static void Main()
    {
        byte[] key = Encoding.UTF8.GetBytes("123456789012345678901234"); // 24 bytes for TripleDES
        byte[] iv = Encoding.UTF8.GetBytes("12345678"); // 8 bytes for TripleDES
        byte[] data = Encoding.UTF8.GetBytes("Hello World!");

        // Encrypt the data
        byte[] encryptedData = TripleDESEncryption.Encrypt(data, key, iv);
        Console.WriteLine("Encrypted data: " + Convert.ToBase64String(encryptedData));

        // Decrypt the data
        byte[] decryptedData = TripleDESEncryption.Decrypt(encryptedData, key, iv);
        Console.WriteLine("Decrypted data: " + Encoding.UTF8.GetString(decryptedData));
    }
}

Best Regards,

Jiale

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