填充无效，无法删除。填充零有效，但 ANSIX923、ISO10126 或 PKCS7 无效

Question

我目前正在尝试编写一个进程来加密以字节流形式发送的文件。 AES 库似乎没有正确应用填充。

当我尝试进行加密时，我得到这样的密码字节：

... 50 57 243 226 18 0 0 0 0 0 0 0 0 0 ... (about 30,000 0s appended to the end)

当我认为我应该得到这样的密码字节时（使用 PKCS7）：

... 50 57 243 226 18 9 9 9 9 9 9 9 9 9

如何让实际的填充方法被识别并像 PKCS7 那样 return 填充？

    Public Function Encrypt(InputStream As Stream) As Byte()

        Dim outputStream = New MemoryStream()

        Dim EncryptionKey As String = "MAKV2SPBNI99212"
        Using encryptor As Aes = Aes.Create()

            Dim pdb As New Rfc2898DeriveBytes(EncryptionKey, New Byte() {&H49, &H76, &H61, &H6E, &H20, &H4D, &H65, &H64, &H76, &H65, &H64, &H65, &H76})
            encryptor.Key = pdb.GetBytes(32)
            encryptor.IV = pdb.GetBytes(16)
            Using cs As New CryptoStream(outputStream, encryptor.CreateEncryptor(), CryptoStreamMode.Write)
                Dim data As Integer
                While (Assign(data, InputStream.ReadByte())) <> -1
                    cs.WriteByte(CByte(data))
                End While
            End Using
        End Using

        Return outputStream.GetBuffer()
    End Function

    Public Function Decrypt(InputStream As Stream) As Byte()

        Dim outputStream = New MemoryStream()

        Dim EncryptionKey As String = "MAKV2SPBNI99212"
        Using encryptor As Aes = Aes.Create()

            Dim pdb As New Rfc2898DeriveBytes(EncryptionKey, New Byte() {&H49, &H76, &H61, &H6E, &H20, &H4D, &H65, &H64, &H76, &H65, &H64, &H65, &H76})
            encryptor.Key = pdb.GetBytes(32)
            encryptor.IV = pdb.GetBytes(16)
            Using cs As New CryptoStream(InputStream, encryptor.CreateDecryptor(), CryptoStreamMode.Read)
                Dim data As Integer
                While (Assign(data, cs.ReadByte())) <> -1
                    outputStream.WriteByte(CByte(data))
                End While
            End Using
        End Using

        Return outputStream.GetBuffer
    End Function

    Private Function Assign(Of T)(ByRef source As T, ByVal value As T) As T
        source = value
        Return value
    End Function

Answer 1

您不应在 returned MemoryStreams 上使用 .GetBuffer 方法。 .GetBuffer returns 底层数组，通常大于流中的数据量。这就是为什么您在末尾看到额外的 0，以及填充无法正确读取的原因。请参阅 the documentation for the MemoryStream.GetBuffer Method

中的备注部分

您应该做的是调用 outputStream.ToArray，这将 return 一个仅包含流中包含的相关数据的字节数组，没有所有尾随 0。

填充无效，无法删除。填充零有效，但 ANSIX923、ISO10126 或 PKCS7 无效

Padding is invalid and cannot be removed. Padding Zeros works but ANSIX923, ISO10126 or PKCS7 do not

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