get byte or image from Crypto Service Provider - vb.net

Question

I used This Code To Encrypt and Decrypt Data In my application
but the code use File Stream to do all work This is the code :
Dim bytKey As Byte()
Dim bytIV As Byte()
bytKey = CreateKey("mrbrashad1999")
bytIV = CreateIV("mrbrashad1999")
Try 'In case of errors.
'Setup file streams to handle input and output.
fsInput = New System.IO.FileStream(strInputFile, FileMode.Open, _
FileAccess.Read)
fsOutput = New System.IO.FileStream(strOutputFile, FileMode.OpenOrCreate, _
FileAccess.Write)
fsOutput.SetLength(0) 'make sure fsOutput is empty
'Declare variables for encrypt/decrypt process.
Dim bytBuffer(4096) As Byte 'holds a block of bytes for processing
Dim lngBytesProcessed As Long = 0 'running count of bytes processed
Dim lngFileLength As Long = fsInput.Length 'the input file's length
Dim intBytesInCurrentBlock As Integer 'current bytes being processed
Dim csCryptoStream As CryptoStream
'Declare your CryptoServiceProvider.
Dim cspRijndael As New System.Security.Cryptography.RijndaelManaged
'Setup Progress Bar
'pbStatus.Value = 0
'pbStatus.Maximum = 100
'Determine if ecryption or decryption and setup CryptoStream.
Select Case Direction
Case CryptoAction.ActionEncrypt
csCryptoStream = New CryptoStream(fsOutput, cspRijndael.CreateEncryptor(bytKey, bytIV), CryptoStreamMode.Write)
Case CryptoAction.ActionDecrypt
csCryptoStream = New CryptoStream(fsOutput, cspRijndael.CreateDecryptor(bytKey, bytIV), CryptoStreamMode.Write)
End Select
'Use While to loop until all of the file is processed.
While lngBytesProcessed < lngFileLength
'Read file with the input filestream.
intBytesInCurrentBlock = fsInput.Read(bytBuffer, 0, 4096)
'Write output file with the cryptostream.
csCryptoStream.Write(bytBuffer, 0, intBytesInCurrentBlock)
'Update lngBytesProcessed
lngBytesProcessed = lngBytesProcessed + CLng(intBytesInCurrentBlock)
'Update Progress Bar
'pbStatus.Value = CInt((lngBytesProcessed / lngFileLength) * 100)
End While
'Close FileStreams and CryptoStream.
csCryptoStream.Close()
fsInput.Close()
fsOutput.Close()
'Catch file not found error.
Catch When Err.Number = 53 'if file not found
MsgBox("Please check to make sure the path and filename" + _
"are correct and if the file exists.", _
MsgBoxStyle.Exclamation, "Invalid Path or Filename")
'Catch all other errors. And delete partial files.
Catch
fsInput.Close()
fsOutput.Close()
End Try
what i should do to get byte() or image From encrypted data in my file system direct to my application variable .

Answer 1

A CryptoStream simply sits on top of another Stream. When you Write to the CryptoStream, it takes the Byte array that you pass in, encrypts it and populates another array with the result, then it will Write that to the underlying Stream. Likewise, when you call Read it will call Read on the underlying Stream, decrypt it and then pass you the result. In your case you are using a FileStream but it can be any type of Stream at all, e.g. NetworkStream or GZipStream. If you want a temporary place to store binary data within your app then you can use a MemoryStream. The code to use the Stream is the same regardless of its type.