vb.net - シリアル化暗号化エラー

Question

オブジェクトを逆シリアル化するときに、シリアル化で暗号化を使用すると問題が発生します。

これはエラーです：

デシリアライズに失敗しました。理由: 解析が完了する前にストリームの終わりが検出されました

これが私のコードです：

Imports System.IO
Imports System.Security.Cryptography
Imports System.Runtime.Serialization
Imports System.Runtime.Serialization.Formatters.Binary
Imports System.Text

Module TestModEncryption

Public Sub SaveEncryptedObjectToFile(FileName As String, Item As Object)
    Dim fs As FileStream
    Dim encryptor As CryptoStream

    Dim formatter As New BinaryFormatter

    Dim password As String = "MyPassword"
    Dim salt As String = "InitialVector123"

    Dim AES As AesManaged = New AesManaged
    AES.Padding = PaddingMode.None
    AES.Mode = CipherMode.CBC

    Dim HashAlgorithm As String = "SHA1" 'Can be SHA1 or MD5
    Dim PasswordIterations As Integer = 2
    Dim InitialVector As String = "InitialVector123" 'This should be a string of 16 ASCII characters.
    Dim KeySize As Integer = 256 'Can be 128, 192, or 256.

    Dim InitialVectorBytes As Byte() = Encoding.ASCII.GetBytes(InitialVector)
    Dim SaltValueBytes As Byte() = Encoding.ASCII.GetBytes(salt)
    Dim DerivedPassword As New Rfc2898DeriveBytes(password, SaltValueBytes, PasswordIterations)
    Dim KeyBytes As Byte() = DerivedPassword.GetBytes(CInt(KeySize / 8))

    Dim encryptTransf As ICryptoTransform = AES.CreateEncryptor(KeyBytes, InitialVectorBytes)

    fs = New FileStream(FileName, FileMode.Create)
    encryptor = New CryptoStream(fs, encryptTransf, CryptoStreamMode.Write)

    Try
        formatter.Serialize(encryptor, Item)
    Catch e As SerializationException
        Console.WriteLine("Failed to serialize. Reason: " & e.Message)
        Throw
    Finally
        fs.Close()
    End Try
End Sub

Public Function OpenEncryptedObjectFromFile(FileName As String) As Object
    Dim fs As New FileStream(FileName, FileMode.Open)
    Dim decryptor As CryptoStream

    Dim ItemToReturn As New Object

    Dim password As String = "MyPassword"
    Dim salt As String = "InitialVector123"

    Dim AES As AesManaged = New AesManaged
    AES.Padding = PaddingMode.None
    AES.Mode = CipherMode.CBC

    Dim HashAlgorithm As String = "SHA1" 'Can be SHA1 or MD5
    Dim PasswordIterations As Integer = 2
    Dim InitialVector As String = "InitialVector123" 'This should be a string of 16 ASCII characters.
    Dim KeySize As Integer = 256 'Can be 128, 192, or 256.

    Dim InitialVectorBytes As Byte() = Encoding.ASCII.GetBytes(InitialVector)
    Dim SaltValueBytes As Byte() = Encoding.ASCII.GetBytes(salt)
    Dim DerivedPassword As New Rfc2898DeriveBytes(password, SaltValueBytes, PasswordIterations)
    Dim KeyBytes As Byte() = DerivedPassword.GetBytes(CInt(KeySize / 8))

    Dim decryptTrans As ICryptoTransform = AES.CreateDecryptor(KeyBytes, InitialVectorBytes)

    Try
        Dim formatter As New BinaryFormatter

        decryptor = New CryptoStream(fs, decryptTrans, CryptoStreamMode.Read)
        ItemToReturn = DirectCast(formatter.Deserialize(decryptor), Object)
        Return ItemToReturn
    Catch e As SerializationException
        MsgBox("Failed to deserialize. Reason: " & e.Message)
        Return Nothing
        'Throw
    Finally
        fs.Close()
    End Try
End Function

End Module