Imports System.Security.Cryptography

Public Class MyEncrypt

Dim EncryptionKey As String = “password scelta da te”

Public Function EncryptString128Bit(ByVal vstrTextToBeEncrypted 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(EncryptionKey) If intLength >= 32 Then EncryptionKey = Strings.Left(EncryptionKey, 32) Else intLength = Len(EncryptionKey) intRemaining = 32 - intLength EncryptionKey = EncryptionKey & Strings.StrDup(intRemaining, “X”) End If bytKey = Encoding.ASCII.GetBytes(EncryptionKey.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) 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 strReturnString As String = String.Empty bytDataToBeDecrypted = Convert.FromBase64String(vstrStringToBeDecrypted) intLength = Len(EncryptionKey) If intLength >= 32 Then EncryptionKey = Strings.Left(EncryptionKey, 32) Else intLength = Len(EncryptionKey) intRemaining = 32 - intLength EncryptionKey = EncryptionKey & Strings.StrDup(intRemaining, “X”) End If bytDecryptionKey = Encoding.ASCII.GetBytes(EncryptionKey.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 Class