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dgsoft
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Group: StrataFrame Users
Posts: 93,
Visits: 236
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Hi,
I try to encrypt and store files in SQL Server database [binarydata] VarChar(MAX) field..
Problem is.. I can't DECRYPT already ecnrypted file.. (with strings I have no problem)
1) Way to encrypt and SaveFile in the Database
Dim loEncrypt As MicroFour.StrataFrame.Security.Encryption.TripleDESWrapper = New MicroFour.StrataFrame.Security.Encryption.TripleDESWrapper
loEncrypt.EncryptFile(lcFilename)
Dim lcSQLExpr = String.Format("UPDATE [ErpData].[dbo].[KONTAKTE_DOKUMENTE] SET [BinaryData] = (SELECT BulkColumn FROM OPENROWSET(BULK '{0}', SINGLE_BLOB) AS InsertData) WHERE PK_ID = {1}", lcFilename, tnDocumentId)
If Me.ExecuteNonQuery(lcSQLExpr) > 0 Then
File.Delete(lcFilename)
End If
==== On this step I encrypt the file and save data into binarydata field
2) I try to restore and decrypt file
' Here is "ME" is businessObject.
Dim fs As FileStream = New FileStream(lcFilename, FileMode.CreateNew, FileAccess.Write)
Dim bw As BinaryWriter = New BinaryWriter(fs)
bw.Write(Me.binarydata, 0, Me.binarydata.Length)
bw.Flush()
bw.Close()
fs.Close()
Dim loEncrypt As MicroFour.StrataFrame.Security.Encryption.TripleDESWrapper = New MicroFour.StrataFrame.Security.Encryption.TripleDESWrapper
Try
loEncrypt.DecryptFile(lcFilename)
lcReturn = lcFilename
Catch ex As Exception
MicroFour.StrataFrame.Messaging.MessageForm.ShowMessage(ex.Message)
End Try
=======! HERE I'V GOT AN EXCEPTION "The length of the encrypted is invalid"
I expect something wrong with BinaryWriter.. but what?
Thanks
Denis
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Greg McGuffey
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Group: Forum Members
Posts: 2K,
Visits: 6.6K
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I don't have time to test your code, but in the mean time there are two things you might test:
First, does the encryption/decryption work if you just encrypt the file, then decrypt it? This would isolate the problem to either the encryption related code or the database related code.
Second, you might consider providing a key and vector to the TripleDESWrapper constructor.
When I get a chance (if you haven't already figured it out), I'll run a quick test to see what I come up with.
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dgsoft
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Group: StrataFrame Users
Posts: 93,
Visits: 236
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Hi Greg,
Thanks for response.
1) Yes. When I do decrypt, and encrypt file on disk - it works perfect.
I thinking the problem with BinaryWriter because my original before attach to database is 184Kb,
And after BinaryWriter.Write file - its 280Kb..
I change my code..
Dim fs As FileStream = New FileStream(lcFilename, FileMode.CreateNew, FileAccess.Write)
Dim bw As BinaryWriter = New BinaryWriter(fs)
Dim encoding As System.Text.ASCIIEncoding = New System.Text.ASCIIEncoding
Dim loBytes As Byte() = encoding.GetBytes(Me.binarydata)
bw.Write(loBytes, 0, loBytes.Length)
bw.Flush()
bw.Close()
fs.Close()
But still have a problem - but now error message is diffrent. It says : Data is invalid..
Probably something wrong with Encoding
Thanks
Denis
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Greg McGuffey
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Group: Forum Members
Posts: 2K,
Visits: 6.6K
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I think the problem might be the EncryptFile method. It is marked as obsolete and apparently causes major file corruption issues. Use the Encrypt/Decrypt methods instead. You can either open a stream and pass the bytes to these methods or read the contents and pass strings: Dim loEncrypt As New TrippleDESWrapper()
Dim contents As String = File.ReadAllText(lcFilename)
Dim encryptedContents As String = loEncrypt.Encrypt(contents)
...
'-- Decrypt code
Dim encryptedContents = myBoInstance.ContentProperty
Dim contents As String = loEncrypt.Decrypt(encryptedContents )
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dgsoft
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Group: StrataFrame Users
Posts: 93,
Visits: 236
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Hi,
Your code works only with Text files.. when I restore binary file like PDF to the disk.. the file is corrupt
RTF file reads ok.. PDF - not
Here I extracting file from database
Private Function mmks_DeryptFile(ByVal tcFilename As String, ByVal tlDecrypt As Boolean)
Dim lcReturnResult As String = tcFilename
Dim contents As String = Me.binarydata
'-- Decrypt code
If tlDecrypt Then
Dim loEncrypt As MicroFour.StrataFrame.Security.Encryption.TripleDESWrapper = New MicroFour.StrataFrame.Security.Encryption.TripleDESWrapper
Dim encryptedContents = Me.binarydata
contents = loEncrypt.Decrypt(encryptedContents)
End If
Dim fs As FileStream = New FileStream(tcFilename, FileMode.CreateNew, FileAccess.Write)
Dim bw As BinaryWriter = New BinaryWriter(fs)
Dim encoding As System.Text.ASCIIEncoding = New System.Text.ASCIIEncoding
Dim loBytes As Byte() = encoding.GetBytes(contents)
bw.Write(loBytes, 0, loBytes.Length)
bw.Flush()
bw.Close()
fs.Close()
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dgsoft
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Group: StrataFrame Users
Posts: 93,
Visits: 236
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Ok.. Now for me it does not work with encoding/ without encoding .. the code next In case when file NOT ENCRYPTED - the binary file stored on the disk correct.
When file is encrypted - I have a next : Encrypting:
1) Dim contents As Byte() = File.ReadAllBytes(lcFilename) LENGHT is 85668
2) Dim encryptedContents As Byte() = loEncrypt.Encrypt(contents) - LENGHT is 85672 Decrypting:
1) Dim encryptedContents As Byte() = System.Text.Encoding.Unicode.GetBytes(contents) - LENGHT is 85672
2) loBytes = loEncrypt.Decrypt(encryptedContents) - LENGHT is 85671 !!!!!!!!!!!!!!!! and as result - file not readable.. Below my code 1) Attach file to the database If KontaktE_DOKUMENTEBO1.isembedded Then
Dim lcFilename As String = KontaktE_DOKUMENTEBO1.location
If File.Exists(lcFilename) Then
If KontaktE_DOKUMENTEBO1.geschuetzt = True Then ' When the document is password protected
Dim loEncrypt As MicroFour.StrataFrame.Security.Encryption.TripleDESWrapper = New MicroFour.StrataFrame.Security.Encryption.TripleDESWrapper
Dim contents As Byte() = File.ReadAllBytes(lcFilename)
Dim encryptedContents As Byte() = loEncrypt.Encrypt(contents)
Me.KontaktE_DOKUMENTEBO1.binarydata = System.Text.Encoding.Unicode.GetString(encryptedContents)
Else
Dim loBytes As Byte() = File.ReadAllBytes(lcFilename)
Me.KontaktE_DOKUMENTEBO1.binarydata = System.Text.Encoding.Unicode.GetString(loBytes)
End If
Try
File.Delete(lcFilename)
Catch ex As Exception
Dim lcMessage = ex.Message
End Try
End If
End If
2) Restore File to the Disk Code
Dim contents As String = Me.binarydata 'BusinessObject VarChar(MAX) field
Dim loBytes As Byte() ' When file neccessary to decrypt - then
If tlDecrypt Then
Dim loEncrypt As MicroFour.StrataFrame.Security.Encryption.TripleDESWrapper = New MicroFour.StrataFrame.Security.Encryption.TripleDESWrapper
Dim encryptedContents As Byte() = System.Text.Encoding.Unicode.GetBytes(contents)
loBytes = loEncrypt.Decrypt(encryptedContents)
Else
' When file not encrypted
loBytes = System.Text.Encoding.Unicode.GetBytes(contents)
End If
Dim fs As FileStream = New FileStream(tcFilename, FileMode.CreateNew, FileAccess.Write)
Dim bw As BinaryWriter = New BinaryWriter(fs)
bw.Write(loBytes, 0, loBytes.Length)
bw.Flush()
bw.Close()
fs.Close()
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dgsoft
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Group: StrataFrame Users
Posts: 93,
Visits: 236
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Ok.
Now problem is fixed.
I choose wrong datatype for SQL Server field.
Now I change it to varbinary(MAX) and all works perfect
Thanks
Denis
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Ivan George Borges
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Group: StrataFrame MVPs
Posts: 1.9K,
Visits: 21K
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Hi Denis. I have created a sample following Greg's code and it works fine over here. To test it, I created a varbinary(MAX) in the Customer table of the StrataFrameSample database and used it to store a .pdf file (you will find it in the project folder itself) called TestPDF.pdf. You can find the sample at the SF Users Contributed Samples (http://forum.strataframe.net/Forum26-1.aspx) There are two buttons, one encrypt the file and save the BO. The other reads the contents of the BO and creates a file on the Desktop (change the line where the FileStream is created to address your Desktop). Hope it helps.
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Greg McGuffey
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Group: Forum Members
Posts: 2K,
Visits: 6.6K
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dgsoft
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Group: StrataFrame Users
Posts: 93,
Visits: 236
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Hi Ivan,
Yes.. my main mistake was using wrong type.. varchar(max) instead varbinary(max), now it works without any conversion operation to string
Thanks for attention
Denis
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