Question

在我们的网络应用程序中，我们有一个上传部分，您可以上传和下载PDF文件。它会在上传时加密它们并在下载时解密它们。它起初工作正常但现在有几个文件损坏了。

某些PDF文件每次都会成功加密和解密，而且每次都会损坏某些PDF文件。我尝试使用我之前知道的相同PDF文件重新测试它，它不再有效。因此，虽然它似乎是特定于文件的，但之前有效的文件不一定有效。

这是我正在使用的加密类：

Public Class clsEncryptFile

Public Sub Encrypt(inputFilePath As String, outputfilePath As String)

    Dim EncryptionKey As String = "FAKEKEY"

    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 fs As New FileStream(outputfilePath, FileMode.Create)
            Using cs As New CryptoStream(fs, encryptor.CreateEncryptor(), CryptoStreamMode.Write)
                Using fsInput As New FileStream(inputFilePath, FileMode.Open)
                    Dim data As Integer

                    While (Assign(data, fsInput.ReadByte())) <> -1
                        cs.WriteByte(CByte(data))
                    End While
                End Using
            End Using
        End Using
    End Using
End Sub

Public Sub Decrypt(inputFilePath As String, outputfilePath As String)
    Dim EncryptionKey As String = "FAKEKEY"
    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 fs As New FileStream(inputFilePath, FileMode.Open)
            Using cs As New CryptoStream(fs, encryptor.CreateDecryptor(), CryptoStreamMode.Read)
                Using fsOutput As New FileStream(outputfilePath, FileMode.Create)
                    Dim data As Integer
                    While (Assign(data, cs.ReadByte())) <> -1
                        fsOutput.WriteByte(CByte(data))
                    End While
                End Using
            End Using
        End Using
    End Using
End Sub

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

End Class

这是加密文件的子程序（使用telerik radasyncupload事件）：

Private Sub _upWorkPapers_FileUploaded(sender As Object, e As Telerik.Web.UI.FileUploadedEventArgs) Handles _upWorkPapers.FileUploaded
    Dim newfilename As String

    newfilename = Session("Asi_Num") & "_" & _hdnNoteDate.Value.Replace("/", "") '& e.File.GetExtension

    e.File.SaveAs(IO.Path.Combine(Server.MapPath(_upWorkPapers.TargetFolder), newfilename & e.File.GetExtension))

    Dim input As String = Convert.ToString(Server.MapPath("/Repository/WorkPapers/") & newfilename) & e.File.GetExtension
    Dim output As String = Convert.ToString((Server.MapPath("/Repository/WorkPapers/") & newfilename) + "_enc") & e.File.GetExtension

    'Encrypt the file
    'crptFile is declared at top of the class as Dim crptFile As New clsEncryptFile
    crptFile.Encrypt(input, output)

    'Set hidden value to store filename
    _hdnFileName.Value = newfilename
    _hdnFileExtension.Value = e.File.GetExtension

    'Delete Original File
    File.Delete(input)

End Sub

这是解密文件的子：

Protected Sub DownloadFile()
    Dim input As String = Convert.ToString((Server.MapPath("/Repository/WorkPapers/") & _hdnFileName.Value) + "_enc") & _hdnFileExtension.Value
    Dim output As String = Convert.ToString((Server.MapPath("/Repository/WorkPapers/") & _hdnFileName.Value) + "_dec") & _hdnFileExtension.Value
    'crptFile is declared at top of class as Dim crptFile As New clsEncryptFile
    crptFile.Decrypt(input, output)

    ''Download the Decrypted File.
    Response.Clear()
    Response.ContentType = "application/pdf"


    Response.AppendHeader("Content-Disposition", "attachment; filename=" + Path.GetFileName(output))
    Response.WriteFile(output)
    Response.Flush()

    'Delete the decrypted (output) file.
    File.Delete(output)

End Sub

自实施以来，这些都没有改变，但突然间它的功能非常不稳定。有没有人对可能造成这种情况有什么想法？

VB.NET中的AES解密不再适用于特定的PDF

0 个答案: