Here it is, I have no idea how it works, but it works great. I use it
to encrypt passwords stored in an access file.
To call it:
'This will encrypt a value
Variable = EncryptString128Bit(txt_Password.Text, EncryptionKey)
'This will decrypt a value
Variable = DecryptString128Bit([Password stored in DB goes here],
EncryptionKey)
Have fun,
Izzy
****************************************************************************
Imports System.Security.Cryptography
Imports System.Text
Module mod_Globals
Public EncryptionKey As String = "justsomewordstobeusedasacryptionkey"
Public Function EncryptString128Bit(ByVal vstrTextToBeEncrypted As
String, ByVal vstrEncryptionKey As String) As String
Dim bytValue() As Byte
Dim bytKey() As Byte
Dim bytEncoded() As Byte
Dim bytIV() As Byte = {121, 241, 10, 1, 132, 74, 11, 39, 255,
91, 45, 78, 14, 211, 22, 62}
Dim intLength As Integer
Dim intRemaining As Integer
Dim objMemoryStream As New MemoryStream
Dim objCryptoStream As CryptoStream
Dim objRijndaelManaged As RijndaelManaged
vstrTextToBeEncrypted =
StripNullCharacters(vstrTextToBeEncrypted)
bytValue =
Encoding.ASCII.GetBytes(vstrTextToBeEncrypted.ToCharArray)
intLength = Len(vstrEncryptionKey)
If intLength >= 32 Then
vstrEncryptionKey = Strings.Left(vstrEncryptionKey, 32)
Else
intLength = Len(vstrEncryptionKey)
intRemaining = 32 - intLength
vstrEncryptionKey = vstrEncryptionKey &
Strings.StrDup(intRemaining, "X")
End If
bytKey = Encoding.ASCII.GetBytes(vstrEncryptionKey.ToCharArray)
objRijndaelManaged = New RijndaelManaged
Try
objCryptoStream = New CryptoStream(objMemoryStream,
objRijndaelManaged.CreateEncryptor(bytKey, bytIV),
CryptoStreamMode.Write)
objCryptoStream.Write(bytValue, 0, bytValue.Length)
objCryptoStream.FlushFinalBlock()
bytEncoded = objMemoryStream.ToArray
objMemoryStream.Close()
objCryptoStream.Close()
Catch
End Try
Return Convert.ToBase64String(bytEncoded)
End Function
Public Function DecryptString128Bit(ByVal vstrStringToBeDecrypted
As String, ByVal vstrDecryptionKey As String) As String
Dim bytDataToBeDecrypted() As Byte
Dim bytTemp() As Byte
Dim bytIV() As Byte = {121, 241, 10, 1, 132, 74, 11, 39, 255,
91, 45, 78, 14, 211, 22, 62}
Dim objRijndaelManaged As New RijndaelManaged
Dim objMemoryStream As MemoryStream
Dim objCryptoStream As CryptoStream
Dim bytDecryptionKey() As Byte
Dim intLength As Integer
Dim intRemaining As Integer
Dim intCtr As Integer
Dim strReturnString As String = String.Empty
Dim achrCharacterArray() As Char
Dim intIndex As Integer
bytDataToBeDecrypted =
Convert.FromBase64String(vstrStringToBeDecrypted)
intLength = Len(vstrDecryptionKey)
If intLength >= 32 Then
vstrDecryptionKey = Strings.Left(vstrDecryptionKey, 32)
Else
intLength = Len(vstrDecryptionKey)
intRemaining = 32 - intLength
vstrDecryptionKey = vstrDecryptionKey &
Strings.StrDup(intRemaining, "X")
End If
bytDecryptionKey =
Encoding.ASCII.GetBytes(vstrDecryptionKey.ToCharArray)
ReDim bytTemp(bytDataToBeDecrypted.Length)
objMemoryStream = New MemoryStream(bytDataToBeDecrypted)
Try
objCryptoStream = New CryptoStream(objMemoryStream,
objRijndaelManaged.CreateDecryptor(bytDecryptionKey, bytIV),
CryptoStreamMode.Read)
objCryptoStream.Read(bytTemp, 0, bytTemp.Length)
objCryptoStream.FlushFinalBlock()
objMemoryStream.Close()
objCryptoStream.Close()
Catch
End Try
Return StripNullCharacters(Encoding.ASCII.GetString(bytTemp))
End Function
Public Function StripNullCharacters(ByVal vstrStringWithNulls As
String) As String
Dim intPosition As Integer
Dim strStringWithOutNulls As String
intPosition = 1
strStringWithOutNulls = vstrStringWithNulls
Do While intPosition > 0
intPosition = InStr(intPosition, vstrStringWithNulls,
vbNullChar)
If intPosition > 0 Then
strStringWithOutNulls = Left$(strStringWithOutNulls,
intPosition - 1) & _
Right$(strStringWithOutNulls,
Len(strStringWithOutNulls) - intPosition)
End If
If intPosition > strStringWithOutNulls.Length Then
Exit Do
End If
Loop
Return strStringWithOutNulls
End Function
End Module
****************************************************************************************
Thanks Izzy,
Dont look too hard for it,
I created my own "encryption array" and flush out certain chars with
others
depending on what value it links up to
with my encryption table.
Just wondering if there is an easier way.
I have a work around though.
Example ( and keep in mind that i have all the alphabet here )
EncryptionKey1 = { A, C, B, D, E, .... }
EncryptionKey2 = { C, D, B, A, E, .... ) 'includes all letters upper and
lower, and also some ascii chars.
and so on ..
Basically if I have a Password that allows for a length of 10. I
actually
store the database as an 11 char field and the first
char is a 123...
If I have the #2 stored in that field and and A was in the pword, then it
gets replaced with a letter C.
If its a B, a D gets put in its spot, and an E, ( in this case stays as
an
E )
I select a random number from 1 to how many encryption keys i have and
thats
the one i use to encrypt it.
Whenever I have to write to the database and I de-crypt it, I re-encrypt
it
with a different Encryption key.
Its simple, and with 30 encryption keys, it does its job.
Any letters that are not in the Encryption key or something like a
special
char, doesnt get convrted and stays as is.
M.
