CryptoStream error when loading from XML file

Question

I am encrypting my data before saving it into the XML file but I am being given the following error when trying to read (load()) from files :

 

System.Security.Cryptography.CryptographicException: 'Bad Data.'

 

The data is written (save()) correctly and is encypted.

 

The following is the save() method:

protected static List Load(string typeName) where T:Person
{
byte[] key = { 1, 2, 3, 4, 5, 6, 7, 8 }; // Where to store these keys is the tricky part,
// you may need to obfuscate them or get the user to input a password each time
byte[] iv = { 1, 2, 3, 4, 5, 6, 7, 8 };
// using (Rijndael rijAlg = Rijndael.Create())
//{
// rijAlg.Key = key;
// rijAlg.IV = iv;
// ICryptoTransform decryptor = rijAlg.CreateDecryptor(key, iv);
// }
//1. Create the result as an empty list
List result = new List();
//2. Create the target directory
string targetDirectory = CreateTargetDirectory(typeName);
//3. Find all the XML files in the target directory
string[] xmlFilePaths = Directory.GetFiles(targetDirectory, "*.xml");
//4. Load each file and deserialize it
//XmlSerializer xmlSerializer = new XmlSerializer(typeof(T));
BinaryFormatter bformatter = new BinaryFormatter();
//added code start >>>
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
//added code end <<<<<
foreach (string xmlFilePath in xmlFilePaths)
{
//using (FileStream dataStream = new FileStream(xmlFilePath, FileMode.Open))
// Decryption
using (var fs = new FileStream(xmlFilePath, FileMode.Open, FileAccess.Read))
using (var cryptoStream = new CryptoStream(fs, des.CreateDecryptor(key, iv), CryptoStreamMode.Read))
{
BinaryFormatter formatter = new BinaryFormatter();
// This is where you deserialize the class
T person = (T)formatter.Deserialize(cryptoStream);
result.Add(person);
}
}
//5. Return the result
return result;
}

The following is the save() method:

protected void Save(string typeName)
{
string targetDirectory = CreateTargetDirectory(typeName);
byte[] key = { 1, 2, 3, 4, 5, 6, 7, 8 }; // Where to store these keys is the tricky part,
// you may need to obfuscate them or get the user to input a password each time
byte[] iv = { 1, 2, 3, 4, 5, 6, 7, 8 };
//2. Generate the path to the target file
string filePath = targetDirectory + ID + ".xml";
//added code start >>>
//using (Stream innerStream = File.Create(filePath));
//added code end <<<<
//3. Serialise the object
//4. Save the object to the target file
//XmlSerializer xmlSerializer = new XmlSerializer(this.GetType());
//added code Start >>>>>
BinaryFormatter bformatter = new BinaryFormatter();
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
//added code end <<<<<<
//using (Stream cryptoStream = new CryptoStream(innerStream, encryptor, CryptoStreamMode.Write))
//{
// 3. write to the cryptoStream
// bformatter.Serialize(cryptoStream, this);
//}
//using (FileStream dataStream = new FileStream(filePath, FileMode.Create))
//Encryption
using (var fs= new FileStream(filePath, FileMode.Create, FileAccess.Write))
using (var cryptoStream = new CryptoStream(fs, des.CreateEncryptor(key, iv), CryptoStreamMode.Write))
{
//xmlSerializer.Serialize(dataStream, this);
//added code start >>>>> https://www.codeproject.com/Articles/1789/Object-Serialization-using-C
//https://stackoverflow.com/questions/1154198/what-are-the-differences-between-the-xmlserializer-and-binaryformatter/1154429
//https://www.codeproject.com/Articles/311944/BinaryFormatter-or-Manual-serializing
//https://stackoverflow.com/questions/48610656/c-sharp-binary-serialization-vs-xmlserializer
//bformatter.Serialize(dataStream, this);
//added code end <<<<<
// dataStream.Close();
bformatter.Serialize(cryptoStream, this);
cryptoStream.Close();
}
}

Can anyone help please, as I am new in C Sharp. The error is being pointed to the line of code at the end of the load method (line 44), which is:

T person = (T)formatter.Deserialize(cryptoStream);