Mornin', I'm trying to just get basic encryption working using System.Security.Cryptography.RjindaelManaged. I have google for this error and cannot find the problem, or what I am doing wrong. All I am attempting to do is encrypt a string, and then decrypt a string.
Following is my code, and any help would be appreciated.
Imports System.Security.Cryptography
Imports System.Text
Public rj As New RijndaelManaged
Try
rj.Padding = PaddingMode.None
rj.GenerateKey()
rj.GenerateIV()
Dim curProvider As New AesCryptoServiceProvider
Dim curEncryptor As ICryptoTransform
Dim memEncStream As New MemoryStream
Dim cryptoEncStream As CryptoStream
curEncryptor = curProvider.CreateEncryptor(rj.Key, rj.IV)
cryptoEncStream = New CryptoStream(memEncStream, curEncryptor, CryptoStreamMode.Write)
Dim startingBytes() As Byte = Encoding.ASCII.GetBytes("This is a test")
Debug.Print("before length: " & startingBytes.Length)
Debug.Print("before text: " & Encoding.ASCII.GetString(startingBytes))
EcryptoEncStream.Write(startingBytes, 0, startingBytes.Length)
cryptoEncStream.FlushFinalBlock()
memEncStream.Position = 0
Dim theBytes(memEncStream.Length) As Byte
memEncStream.Read(theBytes, 0, memEncStream.Length)
memEncStream.Flush()
memEncStream.Close()
cryptoEncStream.Close()
Debug.Print("How long? " & theBytes.Length)
Debug.Print("Data: " & Encoding.ASCII.GetString(theBytes))
Dim curDecryptor As ICryptoTransform
curDecryptor = curProvider.CreateDecryptor(rj.Key, rj.IV)
Dim memDecStream As New MemoryStream
Dim cryptoDecStream As CryptoStream
curDecryptor = curProvider.CreateDecryptor(rj.Key, rj.IV)
cryptoDecStream = New CryptoStream(memDecStream, curDecryptor, CryptoStreamMode.Write)
Dim endingBytes() As Byte = theBytes
Debug.Print("before length: " & theBytes.Length)
Debug.Print("before text: " & Encoding.ASCII.GetString(theBytes))
cryptoDecStream.Write(theBytes, 0, theBytes.Length)
cryptoDecStream.FlushFinalBlock()
memDecStream.Position = 0
Dim endBytes(memDecStream.Length) As Byte
memDecStream.Read(theBytes, 0, memDecStream.Length)
memDecStream.Flush()
memDecStream.Close()
cryptoEncStream.Close()
Debug.Print("How long? " & endBytes.Length)
Debug.Print("Data: " & Encoding.ASCII.GetString(endBytes))
Catch ex As Exception
Debug.Print(ex.ToString)
End Try
You have overridden the PaddingMode and set it None. Why? Leave the PaddingMode to its default value of PaddingMode.PKCS7 unless you have a good reason to change it and you understand padding in a block cipher.
It appears that the problem is the length of the data that you are passing to the decryption stream. If you change the declaration of theBytes from this:
Dim theBytes(memEncStream.Length) As Byte
To this:
Dim theBytes(memEncStream.Length - 1) As Byte
Then it runs fine (at least it did for me). I'm not a VB wizard at all, but I think the array declaration is one byte longer than the given size (I think it is 0 to N). With that extra byte passed to the decryption stream, it does not work.
And I'm sure you will see it soon enough, but your printing of the final decrypted text is not quite right. It is printing theBytes instead of endBytes.
Related
I need a solution to my current code, I am trying to save text to a file from a Text Box, and add a string to it.
My following code is:
Dim fs As FileStream = File.Create(fileName.Text)
' Add text to the file.
Dim info As Byte() = New UTF8Encoding(True).GetBytes(CodeBox.Text)
Dim Code = "-- Made with LUA Creator by Sam v1.9
" + info
fs.Write(Code, 0, Code.Length)
fs.Close()
MsgBox("File saved as " + fileName.Text)
But Visual Studio says that I cannot use "+" operator with strings & bytes:
Error BC30452 Operator '+' is not defined for types 'String' and 'Byte()'.
Anyone have a solution?
Sorry if this is a duplicate, I couldn't find it anywhere here so I just asked myself. Thanks.
"Can I Convert A Byte() to a string?" Short answer is yes, but that doesn't look like what you're really wanting to do.
You're trying to concatenate a String with a Byte array, which Dim Code has no idea what the end result is supposed to be.
FileStream.Write() requires a Byte array so you can try a couple of things
Concatenate the string from the TextBox with your "header" information then turn it into a Byte array.
Dim fs As FileStream = File.Create(fileName.Text)
' Add text to the file.
Dim Code As Byte() = New UTF8Encoding(true).GetBytes("-- Made with LUA Creator by Sam v1.9 " & CodeBox.Text)
fs.Write(Code, 0, Code.Length)
fs.Close()
Write your "header" information, then write the Textbox information
Dim fs As FileStream = File.Create(fileName.Text)
' Add text to the file.
Dim header As Byte() = New UTF8Encoding(true).GetBytes("-- Made with LUA Creator by Sam v1.9 ")
Dim info As Byte() = New UTF8Encoding(True).GetBytes(CodeBox.Text)
fs.Write(header, 0, header.Length)
fs.Write(info, 0, info.Length)
fs.Close()
I have an Access Database linked with a VB project through a data source. In the database on one of the tables, I have an OLE Object field. I have saved pictures in .BMP format and .JPG format in this field. The problem I am encountering is loading this image into my application. This is what I would like to be able to do:
ButtonMeal1.BackgroundImage = IPOSDBDataSet.Meals.Rows(0).Item(5)
Where Item(5) is the column of the row where the image is stored.
Is there another way of doing this. Do I have to load the picture into the program by storing it as a variable, and then using that to change the background image of the button. There are no clear answers on the internet regarding my issue. Please help!
EDIT 1:
After doing some more research, I found some code and adjusted it to try fix my problem.
Dim ImageByteArray As Byte() = CType(IPOSDBDataSet.Meals.Rows(0).Item(5), Byte())
Dim ImageMemoryStream As MemoryStream = New IO.MemoryStream(ImageByteArray)
Dim MyImage As Image = Drawing.Image.FromStream(ImageMemoryStream)
PictureBox1.Image = MyImage
However, I receive the error "Parameter is Not Valid" with the 3rd line of the code. Would anyone be able to tell me how I could adjust my code to fix this issue, or tell me if I am doing something completely wrong?
EDIT 2:
I keep on changing the code around, but the error is always "Parameter is not valid.". What parameter is not valid?
EDIT 3:
No matter what I change it to, the error still persists. What is this parameter that is causing all my issues?
Dim ImageByteArray As Byte() = CType(IPOSDBDataSet.Meals.Rows(0).Item(5), Byte())
Dim ImageMemoryStream As MemoryStream = New IO.MemoryStream(ImageByteArray)
Dim ImageStream As Stream = ImageMemoryStream
Dim MyImage As Image = Drawing.Image.FromStream(ImageStream)
PictureBox1.Image = MyImage
EDIT 4:
Can anyone please help? I really need to be able to implement this into my program. Is there any other possible way of storing images in an access database, and importing them into my vb.net program?
Credit goes to TnTinMan from CodeProject for the answer. Hopefully this helps someone else:
Dim ImageByteArray As Byte() = CType(DataSet.Table.Rows(RowNo).Item(ItemNo), Byte())
Dim ImageMemoryStream As MemoryStream = New IO.MemoryStream(GetImageBytesFromOLEField(ImageByteArray))
Dim MyImage As Image = Drawing.Image.FromStream(ImageMemoryStream)
Friend Shared Function GetImageBytesFromOLEField(ByVal oleFieldBytes() As Byte) As Byte()
Dim BITMAP_ID_BLOCK As String = "BM"
Dim JPG_ID_BLOCK As String = ChrW(&HFF).ToString() & ChrW(&HD8).ToString() & ChrW(&HFF).ToString()
Dim PNG_ID_BLOCK As String = ChrW(&H89).ToString() & "PNG" & vbCrLf & ChrW(&H1A).ToString() & vbLf
Dim GIF_ID_BLOCK As String = "GIF8"
Dim TIFF_ID_BLOCK As String = "II*" & ChrW(&H0).ToString()
Dim imageBytes() As Byte
' Get a UTF7 Encoded string version
Dim u7 As System.Text.Encoding = System.Text.Encoding.UTF7
Dim strTemp As String = u7.GetString(oleFieldBytes)
Dim st2 As String = System.Text.Encoding.UTF8.GetString(oleFieldBytes)
' Get the first 300 characters from the string
Dim strVTemp As String = strTemp.Substring(0, 300)
' Search for the block
Dim iPos As Integer = -1
If strVTemp.IndexOf(BITMAP_ID_BLOCK) <> -1 Then
iPos = strVTemp.IndexOf(BITMAP_ID_BLOCK)
ElseIf strVTemp.IndexOf(JPG_ID_BLOCK) <> -1 Then
iPos = strVTemp.IndexOf(JPG_ID_BLOCK)
ElseIf strVTemp.IndexOf(PNG_ID_BLOCK) <> -1 Then
iPos = strVTemp.IndexOf(PNG_ID_BLOCK)
ElseIf strVTemp.IndexOf(GIF_ID_BLOCK) <> -1 Then
iPos = strVTemp.IndexOf(GIF_ID_BLOCK)
ElseIf strVTemp.IndexOf(TIFF_ID_BLOCK) <> -1 Then
iPos = strVTemp.IndexOf(TIFF_ID_BLOCK)
Else
Throw New Exception("Unable to determine header size for the OLE Object")
End If
' From the position above get the new image
If iPos = -1 Then
Throw New Exception("Unable to determine header size for the OLE Object")
End If
imageBytes = New Byte(CInt(oleFieldBytes.LongLength - iPos - 1)) {}
Array.ConstrainedCopy(oleFieldBytes, iPos, imageBytes, 0, oleFieldBytes.Length - iPos)
Return imageBytes
End Function
There isn't really such a thing as an 'image' stored in an Access table, only a binary stream. Therefore, the left hand side of your expression doesn't know that the right hand side is providing an image. You would have to stream the binary stream into a stream in VB.NET, then use System.Graphics methods to make it into a BMP or PNG or whatever. You could assign that object to the button.
still show error: index and length must refer to a location within the string.Parameter name: len
I've got a problem to make two applications to send text-data between themselves.
The message is transmitted without any problems, the answer is received too. But, there is a lot of a "New line" char in the end of the string send/received on each side.
I guess it's because of I'm reading the full buffer; I've tried to remove all Chr(10) and Chr(13); I also tried to trim the string, but it didn't worked.
Here the code I use :
Client Side :
Dim cl As New TcpClient
cl.Connect("127.0.0.1", 2000)
Dim str As NetworkStream = cl.GetStream
Dim HelloInBytes As Byte() = Encoding.UTF8.GetBytes("Hello")
str.Write(HelloInBytes, 0, HelloInBytes.Length)
Dim Buffer(cl.ReceiveBufferSize) As Byte
str.Read(Buffer, 0, cl.ReceiveBufferSize)
Console.WriteLine(Encoding.UTF8.GetChars(Buffer))
Server Side :
Dim srv As New TcpListener(IPAddress.Any, 2000)
srv.Start()
Dim cl As TcpClient = srv.AcceptTcpClient
Dim str As NetworkStream = cl.GetStream
Dim buf(cl.ReceiveBufferSize) As Byte
str.Read(buf, 0, cl.ReceiveBufferSize)
Dim res As Byte() = Encoding.UTF8.GetBytes("World")
str.Write(res, 0, res.Length)
Is there a way to "clean" the received string ?
Thanks for help.
EDIT : Solution :
It Works with Harzcle solution.
I found another solution which is to use this function on the received string :
Public Function CleanString(ByRef Str As String)
Return Str.Replace(Encoding.UTF8.GetChars({0, 0, 0, 0}), Nothing)
End Function
UTF8 works on 4 bytes, and when I read the stream and I put it into a buffer, if there is no char, the 4 bytes stay on a 0 value.
Use Flush() after you write into the buffer
str.Write(HelloInBytes, 0, HelloInBytes.Length)
str.Flush()
And
str.Write(res, 0, res.Length)
str.Flush()
Edit:
You can use a delimiter or something like that.
Client side:
Dim delimiterChar as Char = "|"
Dim out As Byte() = System.Text.Encoding.UTF8.GetBytes(txtOut.Text + delimiterChar)
server.Write(outStream, 0, outStream.Length)
server.Flush()
And Server side:
Dim delimiterChar as Char = "|"
Dim Stream As NetworkStream = clientSocket.GetStream()
Stream.Read(bytesFrom, 0, CInt(client.ReceiveBufferSize))
Dim data As String = System.Text.Encoding.UTF8.GetString(bytesFrom)
data = data.Substring(0, data.IndexOf(delimiterChar)) 'From 0 to delimiter
This will remove all null characters at the end of the received string
client_content = client_content.Replace(Chr(0), Nothing)
To remove new lines:
client_content = client_content.Replace(vbLf, Nothing)
I have a encryption/decryption method that works just fine with one exception. When I attempt to read in encrypted text from a text file and then decrypt it I get the following error.
Invalid character in a Base-64 string
The strange thing is if I just read the encrypted text into a textbox and then copy and pate it into another text box that decrypts used the same decryption method it works just fine. No errors and the decryption proceeds. I am listing the decryption method and method used to read in the text file below.
Decryption Method
Public Shared Function DecryptUserString(ByRef cipheredText As String, ByRef password As String) As String
Dim RijndaelManagedObj As New RijndaelManaged
Dim RijndaelEncObj As ICryptoTransform, MD5Obj As New MD5CryptoServiceProvider
Dim DecryptedBytes As Byte(), EncryptedData As Byte()
Dim PasswordBytes As Byte() = New ASCIIEncoding().GetBytes(password)
Dim UTF8Encoding As System.Text.Encoding = System.Text.Encoding.UTF8
'A modified Base64 is sent with ~ and - so it can be sent as a form post
EncryptedData = Convert.FromBase64String(Replace(Replace(cipheredText, "~", "+"), "-", "="))
RijndaelManagedObj.BlockSize = 128
RijndaelManagedObj.KeySize = 128
RijndaelManagedObj.Mode = CipherMode.ECB
RijndaelManagedObj.Padding = PaddingMode.None
RijndaelManagedObj.Key = MD5Obj.ComputeHash(PasswordBytes)
RijndaelEncObj = RijndaelManagedObj.CreateDecryptor()
DecryptedBytes = RijndaelEncObj.TransformFinalBlock(EncryptedData, 0, EncryptedData.Length)
If DecryptedBytes.Length > 0 Then
DecryptUserString = UTF8Encoding.GetString(DecryptedBytes, 0, DecryptedBytes.Length)
If DecryptedBytes.Length = 0 Then DecryptUserString = New ASCIIEncoding().GetString(DecryptedBytes)
Else
DecryptUserString = ""
End If
End Function
Method to read text from file
Private Function ReadText(ByVal TextFilePath As String) As String
Using ReadStream As FileStream = File.OpenRead(TextFilePath)
Dim FileTextBuilder As New StringBuilder()
Dim DataTransit As Byte() = New Byte(ReadStream.Length) {}
Dim DataEncoding As New UTF8Encoding(True)
While ReadStream.Read(DataTransit, 0, DataTransit.Length) > 0
FileTextBuilder.Append(DataEncoding.GetString(DataTransit))
End While
Return FileTextBuilder.ToString()
End Using
End Function
Can't you use File.ReadAllText() method to read the whole file and then decrypt the same way you do with textboxes?
I know, if file is huge that's not a good idea, but you can give it a try to see if file is well saved or if you're reading it bad.
As a hobby I'm interesting in programming an Ethernet-connected LED sign to scroll messages across a screen. But I'm having trouble making a UDP sender in VB.NET (I am using 2008 currently).
Now the sign is nice enough to have a specifications sheet on programming for it.
But an example of a line to send to it (page 3):
<0x01>Z30<0x02>AA<0x06><0x1B>0b<0x1C>1<0x1A>1This message will show up on the screen<0x04>
With codes such as <0x01> representing the hex character.
Now, to send this to the sign I need to use UDP. However, the examples I have all encode the message as ASCII before sending, like this one (from UDP: Client sends packets to, and receives packets from, a server):
Imports System.Threading
Imports System.Net.Sockets
Imports System.IO
Imports System.Net
Public Class MainClass
Shared Dim client As UdpClient
Shared Dim receivePoint As IPEndPoint
Public Shared Sub Main()
receivePoint = New IPEndPoint(New IPAddress(0), 0)
client = New UdpClient(8888)
Dim thread As Thread = New Thread(New ThreadStart(AddressOf WaitForPackets))
thread.Start()
Dim packet As String = "client"
Console.WriteLine("Sending packet containing: ")
'
' Note the following line below, would appear to be my problem.
'
Dim data As Byte() = System.Text.Encoding.ASCII.GetBytes(packet)
client.Send(data, data.Length, "localhost", 5000)
Console.WriteLine("Packet sent")
End Sub
Shared Public Sub WaitForPackets()
While True
Dim data As Byte() = client.Receive(receivePoint)
Console.WriteLine("Packet received:" & _
vbCrLf & "Length: " & data.Length & vbCrLf & _
System.Text.Encoding.ASCII.GetString(data))
End While
End Sub ' WaitForPackets
End Class
To output a hexcode in VB.NET, I think the syntax may possibly be &H1A - to send what the specifications would define as <0x1A>.
Could I modify that code, to correctly send a correctly formated packet to this sign?
The answers from Grant (after sending a packet with hex in it), Hamish Smith (using a function to get hex values), and Hafthor (hardcoded chr() message into example) when attempted all did not work. So I'll research to see what else could go wrong. In theory, if this string is sent successfully, I should have a message containing "OK" back, which will help to know when it works.
I have tried and am now able to monitor the packets going through. A working packet example is this (in raw hex): http://www.brettjamesonline.com/misc/forums/other/working.raw vs my version: http://www.brettjamesonline.com/misc/forums/other/failed.raw. The difference is my hex codes are still not encoded correctly, seen in this side-by-side image: http://www.brettjamesonline.com/misc/forums/other/snapshotcoding.png.
I have used this code to generate the packet and send it:
container = &H1 & "Z" & &H30 & &H2 & "temp.nrg" & &H1C & "1Something" & &H4
' This did not appear to work neither
'container = Chr(&H1) & "Z" & Chr(&H30) & Chr(&H2) & Chr(&H1C) & "1Something" & Chr(&H4)
'<0x01>Z00<0x02>FILENAME<0x1C>1Test to display<0x04> <- the "official" spec to send
Dim sendBytes As [Byte]() = Encoding.ASCII.GetBytes(container)
(Full snippet: http://pastebin.com/f44417743.)
You could put together a quickie decoder like this one:
Function HexCodeToHexChar(ByVal m as System.Text.RegularExpressions.Match) As String
Return Chr(Integer.Parse(m.Value.Substring("<0x".Length, 2), _
Globalization.NumberStyles.HexNumber))
End Function
then use this to transform:
Dim r As New System.Text.RegularExpressions.Regex("<0x[0-9a-fA-F]{2}>")
Dim s As String = r.Replace("abc<0x44>efg", AddressOf HexCodeToHexChar)
' s should now be "abcDefg"
you could also make an encoder function that undoes this decoding (although a little more complicated)
Function HexCharToHexCode(ByVal m As Match) As String
If m.Value.StartsWith("<0x") And m.Value.EndsWith(">") And m.Value.Length = "<0x??>".Length Then
Return "<0<0x78>" + m.Value.Substring("<0x".Length)
ElseIf Asc(m.Value) >= 0 And Asc(m.Value) <= &HFF Then
Return "<0x" + Right("0" + Hex(Asc(m.Value)), 2) + ">"
Else
Throw New ArgumentException("Non-SBCS ANSI characters not supported")
End If
End Function
and use this to transform:
Dim r As New Regex("[^ -~]|<0x[0-9a-fA-F]{2}>")
Dim s As String = r.Replace("abc"+chr(4)+"efg", AddressOf HexCharToHexCode)
' s should now be "abc<0x04>efg"
or you could just build the string with the special characters in it to begin with like this:
Dim packet As String = Chr(&H01) + "Z30" + Chr(&H02) + "AA" + Chr(&H06) + _
Chr(&H1B) + "0b" + Chr(&H1C) + "1" + Chr(&H1A) + _
"1This message will show up on the screen" + Chr(&H04)
for sending a UDP packet, the following should suffice:
Dim i As New IPEndPoint(IPAddress.Parse("192.168.0.5"), 3001) ''//Target IP:port
Dim u As New UdpClient()
Dim b As Byte() = Encoding.UTF8.GetBytes(s) ''//Where s is the decoded string
u.Send(b, b.Length, i)
This might help. At my company we have to communicate with our hardware using sort of a combination of ascii and hex.
I use this function to hexify ip addresses before sending them to the hardware
Public Function HexFromIP(ByVal sIP As String)
Dim aIP As String()
Dim sHexCode As String = ""
aIP = sIP.Split(".")
For Each IPOct As String In aIP
sHexCode += Hex(Val(IPOct)).PadLeft(2, "0")
Next
Return sHexCode
End Function
And occationally I use hexSomething = Hex(Val(number)).PadLeft(2,"0") as well.
I can give you the source for the whole program too, though it's designed to talk to different hardware.
EDIT:
Are you trying to send packets in hex, or get packets in hex?
The UDP client sends an array of bytes.
You could use a memory stream and write bytes to an array.
Public Class MainClass
Shared client As UdpClient
Shared receivePoint As IPEndPoint
Public Shared Sub Main()
receivePoint = New IPEndPoint(New IPAddress(0), 0)
client = New UdpClient(8888)
Dim thread As Thread = New Thread(New ThreadStart(AddressOf WaitForPackets))
thread.Start()
Dim packet As Packet = New Packet("client")
Console.WriteLine("Sending packet containing: ")
Dim data As Byte() = packet.Data
client.Send(data, data.Length, "localhost", 5000)
Console.WriteLine("Packet sent")
End Sub
Public Shared Sub WaitForPackets()
While True
Dim data As Byte() = client.Receive(receivePoint)
Console.WriteLine("Packet received:" & _
vbCrLf & "Length: " & data.Length & vbCrLf & _
System.Text.Encoding.ASCII.GetString(data))
End While
End Sub ' WaitForPackets
End Class
Public Class Packet
Private _message As String
Public Sub New(ByVal message As String)
_message = message
End Sub
Public Function Data() As Byte()
Dim ret(13 + _message.Length) As Byte
Dim ms As New MemoryStream(ret, True)
ms.WriteByte(&H1)
'<0x01>Z30<0x02>AA<0x06><0x1B>0b<0x1C>1<0x1A>1This message will show up on the screen<0x04>
ms.Write(System.Text.Encoding.ASCII.GetBytes("Z30"), 0, 3)
ms.WriteByte(&H2)
ms.Write(System.Text.Encoding.ASCII.GetBytes("AA"), 0, 2)
ms.WriteByte(&H6)
ms.Write(System.Text.Encoding.ASCII.GetBytes("0b"), 0, 2)
ms.WriteByte(&H1C)
ms.Write(System.Text.Encoding.ASCII.GetBytes("1"), 0, 1)
ms.WriteByte(&H1A)
ms.Write(System.Text.Encoding.ASCII.GetBytes(_message), 0, _message.Length)
ms.WriteByte(&H4)
ms.Close()
Data = ret
End Function
End Class
They posted libraries for a bunch of languages including Visual Basic (in the separate file). I tested the demos out with one of their signs and they work!
http://support.favotech.com