AES 函数总是以空结果回复

Question

今天我有一个关于我当前要进行的 Visual Basic 项目的问题。我的意图是在可执行文件所在的同一目录中为我的程序提供一个或多个加密的配置文件。因为很可能（en/de）加密将被处理两次（用户名和密码），我想（ en/de)crypt 直接从字符串到字符串。我希望这将减少临时文件的麻烦，并且以后可能会有用。

在这个伟大的网站和另一个教程的帮助下，至少编译器不再抱怨了。 :) 到目前为止，一切都很好......

我的代码如下：

   Private Function produceKeyandIV(ByVal Password As String) As Object()
    Dim ByteArray(Password.Length) As Byte, Key(31) As Byte, IV(15) As Byte
    ByteArray = System.Text.Encoding.ASCII.GetBytes(Password)
    Dim SHA_FUNCTION As New System.Security.Cryptography.SHA512Managed
    Dim HashResult As Byte() = SHA_FUNCTION.ComputeHash(ByteArray)
    Array.Copy(HashResult, Key, 32)
    Array.Copy(HashResult, 32, IV, 0, 16)
    Dim obj(2) As Object
    obj(0) = Key
    obj(1) = IV
    Return obj
End Function
Private Function GenerateStreamFromString(ByVal myString As String) As Stream
    Dim ret_stream As MemoryStream = New MemoryStream()
    Dim stream_writer As StreamWriter = New StreamWriter(ret_stream, Encoding.Default)
    stream_writer.Write(myString)
    stream_writer.Flush()
    ret_stream.Position = 0
    Return ret_stream
End Function
Public Function DecryptStringReturnString(ByVal EncryptedString As String, ByVal Key As String) As String
    Dim CryptographyParameters As Object() = produceKeyandIV(Key)
    Try
        Dim byteBuffer(4096) As Byte
        Dim memoryStreamIn As Stream = GenerateStreamFromString(EncryptedString)
        Dim memoryStreamOut As MemoryStream = New MemoryStream()
        Dim positionInString As Long = 0
        Dim StringLength As Long = EncryptedString.Length()
        Dim bytesInBlockProcessed As Integer = 0
        Dim cryptServiceProvRijn As New System.Security.Cryptography.RijndaelManaged
        Using sCryptoStream = New CryptoStream(memoryStreamOut, _
                                              cryptServiceProvRijn.CreateDecryptor(CryptographyParameters(0), CryptographyParameters(1)), _
                                              CryptoStreamMode.Write)
            While positionInString < StringLength
                bytesInBlockProcessed = memoryStreamIn.Read(byteBuffer, 0, 4096)
                sCryptoStream.Write(byteBuffer, 0, bytesInBlockProcessed)
                positionInString = positionInString + (bytesInBlockProcessed)
            End While
        End Using
        memoryStreamIn.Close()
        memoryStreamOut.Position = 0
        Dim stream_reader As StreamReader = New StreamReader(memoryStreamOut)
        Return stream_reader.ReadToEnd()
    Catch ex As Exception

    End Try
    Return Nothing
End Function
Public Function EncryptStringReturnString(ByVal DecryptedString As String, ByVal Key As String) As String
    Dim CryptographyParameters As Object() = produceKeyandIV(Key)
    Try
        Dim byteBuffer(4096) As Byte
        Dim memoryStreamIn As Stream = GenerateStreamFromString(DecryptedString)
        Dim memoryStreamOut As MemoryStream = New MemoryStream()
        Dim positionInString As Long = 0
        Dim StringLength As Long = DecryptedString.Length()
        Dim bytesInBlockProcessed As Integer = 0
        Dim cryptServiceProvRijn As New System.Security.Cryptography.RijndaelManaged
        Using sCryptoStream = New CryptoStream(memoryStreamOut, _
                                              cryptServiceProvRijn.CreateEncryptor(CryptographyParameters(0), CryptographyParameters(1)), _
                                              CryptoStreamMode.Write)
            While positionInString < StringLength
                bytesInBlockProcessed = memoryStreamIn.Read(byteBuffer, 0, 4096)
                sCryptoStream.Write(byteBuffer, 0, bytesInBlockProcessed)
                positionInString = positionInString + (bytesInBlockProcessed)
            End While
            memoryStreamIn.Close()
            memoryStreamOut.Position = 0
            Dim stream_reader As StreamReader = New StreamReader(memoryStreamOut)
            Return stream_reader.ReadToEnd()
        End Using
    Catch ex As Exception

    End Try
    Return Nothing
End Function

问题是如果我调用函数并让我打印给出结果，它们总是空的。也许其他人知道为什么？ :)

提前感谢您的帮助...

有用的资源：

• how to generate a stream from a string?
• http://www.codeproject.com/Articles/12092/Encrypt-Decrypt-Files-in-VB-NET-Using-Rijndael 这些对我的项目帮助很大。

Answer 1

缺少一条指令。根据this website 需要FlushFinalBlock()，以便最终确定对 CryptoStream 所做的更改。那边的人还建议将数据实际存储在字节数组中，而不是转换后的字符串中。我将在进一步的开发中这样做，只有在最后，如果配置需要清晰可读，它将被转换回“可读”文本。

这是我以前源代码的“固定”版本：

Imports System.IO
Imports System.Security.Cryptography
Imports System.Text

Module sandbox
    Private Function produceKeyandIV(ByVal Password As String) As Object()
        Dim ByteArray(Password.Length) As Byte, Key(31) As Byte, IV(15) As Byte
        ByteArray = System.Text.Encoding.ASCII.GetBytes(Password)
        Dim SHA_FUNCTION As New System.Security.Cryptography.SHA512Managed
        Dim HashResult As Byte() = SHA_FUNCTION.ComputeHash(ByteArray)
        Array.Copy(HashResult, Key, 32)
        Array.Copy(HashResult, 32, IV, 0, 16)
        Dim obj(2) As Object
        obj(0) = Key
        obj(1) = IV
        Return obj
    End Function
    Private Function GenerateStreamFromString(ByVal myString As String) As Stream
        Dim ret_stream As MemoryStream = New MemoryStream()
        Dim stream_writer As StreamWriter = New StreamWriter(ret_stream, Encoding.Default)
        stream_writer.Write(myString)
        stream_writer.Flush()
        ret_stream.Position = 0
        Return ret_stream
    End Function
    Public Function DecryptByteArrayReturnByteArray(ByVal Encrypted As Byte(), ByVal Key As String) As Byte()
        Dim CryptographyParameters As Object() = produceKeyandIV(Key)
        Try
            Dim byteBuffer(4096) As Byte
            Dim memoryStreamIn As Stream = New MemoryStream(Encrypted)
            Dim memoryStreamOut As MemoryStream = New MemoryStream()
            Dim position As Long = 0
            Dim bytesInBlockProcessed As Integer = 0
            Dim cryptServiceProvRijn As New System.Security.Cryptography.RijndaelManaged
            Using sCryptoStream = New CryptoStream(memoryStreamOut, _
                                                  cryptServiceProvRijn.CreateDecryptor(CryptographyParameters(0), CryptographyParameters(1)), _
                                                  CryptoStreamMode.Write)
                While position < Encrypted.Count()
                    bytesInBlockProcessed = memoryStreamIn.Read(byteBuffer, 0, 4096)
                    sCryptoStream.Write(byteBuffer, 0, bytesInBlockProcessed)
                    sCryptoStream.Flush()
                    position = position + (bytesInBlockProcessed)
                End While
                memoryStreamIn.Close()
                sCryptoStream.FlushFinalBlock() ' Needed to close the CryptoStream properly (a simple flush is not enough)
                Return memoryStreamOut.ToArray ' Independent from actual Streamposition
            End Using
        Catch ex As Exception

        End Try
        Return Nothing
    End Function
    Public Function EncryptByteArrayReturnByteArray(ByVal Decrypted As Byte(), ByVal Key As String) As Byte()
        Dim CryptographyParameters As Object() = produceKeyandIV(Key)
        Try
            Dim byteBuffer(4096) As Byte
            Dim memoryStreamIn As Stream = New MemoryStream(Decrypted)
            Dim memoryStreamOut As MemoryStream = New MemoryStream()
            Dim position As Long = 0
            Dim bytesInBlockProcessed As Integer = 0
            Dim cryptServiceProvRijn As New System.Security.Cryptography.RijndaelManaged
            Using sCryptoStream = New CryptoStream(memoryStreamOut, _
                                                  cryptServiceProvRijn.CreateEncryptor(CryptographyParameters(0), CryptographyParameters(1)), _
                                                  CryptoStreamMode.Write)
                While position < Decrypted.Count()
                    bytesInBlockProcessed = memoryStreamIn.Read(byteBuffer, 0, 4096)
                    sCryptoStream.Write(byteBuffer, 0, bytesInBlockProcessed)
                    sCryptoStream.Flush()
                    position = position + (bytesInBlockProcessed)
                End While
                memoryStreamIn.Close()
                sCryptoStream.FlushFinalBlock() ' Needed to close the CryptoStream properly (a simple flush is not enough)
                Return memoryStreamOut.ToArray ' Independent from actual Streamposition
            End Using
        Catch ex As Exception

        End Try
        Return Nothing
    End Function
    Sub Main()
        Console.Write("Passwort: ")
        Dim pwd = Console.ReadLine()
        Dim x As String = New String((System.Text.Encoding.Default.GetChars(DecryptByteArrayReturnByteArray(EncryptByteArrayReturnByteArray(System.Text.Encoding.Default.GetBytes(pwd), pwd), pwd))))
        Console.Write(x)
        Console.ReadLine()
    End Sub

End Module

如果您认为代码中存在问题或缺陷，请为我指出。我非常感谢。 :)