Rijndael管理:明文长度检测 [英] Rijndael managed: plaintext length detction

问题描述

我花了一些时间来学习如何在.NET中使用RijndaelManaged库，并开发了以下功能来测试对文本的加密，并对该MSDN库进行了一些修改:

I am spending some time learning how to use the RijndaelManaged library in .NET, and developed the following function to test encrypting text with slight modifications from the MSDN library:

Function encryptBytesToBytes_AES(ByVal plainText As Byte(), ByVal Key() As Byte, ByVal IV() As Byte) As Byte()
        ' Check arguments.
        If plainText Is Nothing OrElse plainText.Length <= 0 Then
            Throw New ArgumentNullException("plainText")
        End If
        If Key Is Nothing OrElse Key.Length <= 0 Then
            Throw New ArgumentNullException("Key")
        End If
        If IV Is Nothing OrElse IV.Length <= 0 Then
            Throw New ArgumentNullException("IV")
        End If

        ' Declare the RijndaelManaged object
        ' used to encrypt the data.
        Dim aesAlg As RijndaelManaged = Nothing

        ' Declare the stream used to encrypt to an in memory
        ' array of bytes.
        Dim msEncrypt As MemoryStream = Nothing

        Try
            ' Create a RijndaelManaged object
            ' with the specified key and IV.
            aesAlg = New RijndaelManaged()
            aesAlg.BlockSize = 128
            aesAlg.KeySize = 128
            aesAlg.Mode = CipherMode.ECB
            aesAlg.Padding = PaddingMode.None
            aesAlg.Key = Key
            aesAlg.IV = IV

                ' Create a decrytor to perform the stream transform.
                Dim encryptor As ICryptoTransform = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV)

                ' Create the streams used for encryption.
                msEncrypt = New MemoryStream()
                Using csEncrypt As New CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write)
                    Using swEncrypt As New StreamWriter(csEncrypt)

                        'Write all data to the stream.
                        swEncrypt.Write(plainText)
                    End Using
                End Using

        Finally
            ' Clear the RijndaelManaged object.
            If Not (aesAlg Is Nothing) Then
                aesAlg.Clear()
            End If
        End Try
        ' Return the encrypted bytes from the memory stream.
        Return msEncrypt.ToArray()

    End Function

这是我用以下命令调用cryptoBytesToBytes_AES()的实际代码:

Here's the actual code I am calling encryptBytesToBytes_AES() with:

Private Sub btnEncrypt_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnEncrypt.Click
    Dim bZeroKey As Byte() = {&H0, &H0, &H0, &H0, &H0, &H0, &H0, &H0, &H0, &H0, &H0, &H0, &H0, &H0, &H0, &H0}
    PrintBytesToRTF(encryptBytesToBytes_AES(bZeroKey, bZeroKey, bZeroKey))
End Sub

但是，我在swEncrypt.Write(plainText)上抛出了一个异常，指出要加密的数据长度无效".

However, I get an exception thrown on swEncrypt.Write(plainText) stating that the 'Length of the data to encrypt is invalid.'

但是，我知道密钥，iv和纯文本的大小为16个字节== 128位== aesAlg.BlockSize. 为什么会引发此异常?，是因为StreamWriter试图创建一个String(表面上使用某种编码)，并且它不喜欢& H0作为值吗?

However, I know that the size of my key, iv, and plaintext are 16 bytes == 128 bits == aesAlg.BlockSize. Why is it throwing this exception? Is it because the StreamWriter is trying to make a String (ostensibly with some encoding) and it doesn't like &H0 as a value?

我认为除了使用StreamWriter之外，我还需要想出一种加密字节数组的新方法. MSDN页面上的雄鹿显示这将首先执行某种字符串转换，这是我不想要的.有什么想法吗?

I think I need to come up with a new way to encrypt the byte array, other than using the StreamWriter. A gander on the MSDN page shows that this will do some sort of string conversion first, which I don't want. Any ideas?

推荐答案

在这种情况下，您不能也不需要使用StreamWriter.
StreamWriter不接受Byte()作为参数.

You cannot and don't need to use a StreamWriter in this case.
StreamWriter doesn't accept Byte() as an argument.

您可以将加密功能修改为以下内容:

You can modify your encryption function to the following:

Function encryptBytesToBytes_AES(ByVal plainText As Byte(), ByVal Key() As Byte, ByVal IV() As Byte) As Byte()
    ' Check arguments.'
    If plainText Is Nothing OrElse plainText.Length <= 0 Then
        Throw New ArgumentNullException("plainText")
    End If
    If Key Is Nothing OrElse Key.Length <= 0 Then
        Throw New ArgumentNullException("Key")
    End If
    If IV Is Nothing OrElse IV.Length <= 0 Then
        Throw New ArgumentNullException("IV")
    End If

    ' Declare the RijndaelManaged object'
    ' used to encrypt the data.'
    Dim aesAlg As RijndaelManaged = Nothing

    Dim encryptedData As Byte()

    Try
        ' Create a RijndaelManaged object'
        ' with the specified key and IV.'
        aesAlg = New RijndaelManaged()
        aesAlg.BlockSize = 128
        aesAlg.KeySize = 128
        aesAlg.Mode = CipherMode.ECB
        aesAlg.Padding = PaddingMode.None
        aesAlg.Key = Key
        aesAlg.IV = IV

        ' Create a decrytor to perform the stream transform.'
        Dim encryptor As ICryptoTransform = aesAlg.CreateEncryptor()

        ' Create the streams used for encryption.'
        Using msEncrypt As New MemoryStream()

            Using csEncrypt As New CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write)
                csEncrypt.Write(plainText, 0, plainText.Length)
                csEncrypt.FlushFinalBlock()
            End Using
            encryptedData = msEncrypt.ToArray()
        End Using

    Finally
        ' Clear the RijndaelManaged object.'
        If Not (aesAlg Is Nothing) Then
            aesAlg.Clear()
        End If
    End Try
    ' Return the encrypted bytes from the memory stream.'
    Return encryptedData
End Function

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