I had to revisit this functionality today. I am pretty certain that I tested decrypting back to a dataset with the previous method I was using, but today it just wouldn’t work at all. After a lot of reading, googling and research, I learned a lot about various methods of cryptography, yet I was still unable to solve my problem on my own. Finally I came upon a code sample (not in the first 4 searches, mind you!) and thought I better persist THAT here!! Here is the link. If for some reason that link goes away here’s my particular (VB.Net) treatment of the code:
Public Sub encryptDS(ByVal ds As DataSet, ByVal filename As String)
Dim aCryptoStream As CryptoStream
Try
Dim aXmlTextWriter As XmlTextWriter
aXmlTextWriter = New XmlTextWriter(filename, Text.Encoding.UTF8)
Dim aUE As New Text.UnicodeEncoding
Dim keyBytes() As Byte = {……} ‘your secret bytes go here
Dim RMCrypto As RijndaelManaged = New RijndaelManaged
aCryptoStream = New CryptoStream(aXmlTextWriter.BaseStream, RMCrypto.CreateEncryptor(keyBytes, keyBytes), CryptoStreamMode.Write)
ds.WriteXml(aCryptoStream)
Catch ex As Exception
…
Finally
aCryptoStream.Close()
End Try
End Sub Public Sub DecryptDS(ByRef ds As DataSet, ByVal filename As String)
Dim aFileStream As New FileStream(filename, FileMode.Open)
Dim aStreamReader As StreamReader
Try
aStreamReader = New StreamReader(aFileStream)
Dim aUE As New Text.UnicodeEncoding
Dim keyBytes() As Byte = {….} ‘ your secret bytes go here
Dim RMCrypto As RijndaelManaged = New RijndaelManaged
Dim aCryptoStream As New CryptoStream(aFileStream, RMCrypto.CreateDecryptor(keyBytes, keyBytes), CryptoStreamMode.Read)
‘Restore the data set
ds.ReadXml(aCryptoStream)
Catch exS As IOException
…
Catch ex As Exception
…
Finally
aStreamReader.Close()
aFileStream.Close()
End Try
End Sub |
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