Encriptando Cookies

Aquí les dejo fragmento de un código que les puede ser útil a la hora de encriptar cookies en sus aplicaciones.

 

 

Imports System.Security.Cryptography.Rfc2898DeriveBytes

Imports System.Security.Cryptography

Imports System.IO

Partial Class _Default

    Inherits System.Web.UI.Page

    Public Function DecryptString(ByVal inString As String, ByVal password As String, ByVal Mysalt As String) As String

        Dim DescryText As String = “”

        Try

 

            Dim myAlg As RijndaelManaged = New RijndaelManaged()

            Dim salt As Byte() = System.Text.Encoding.ASCII.GetBytes(Mysalt)

            Dim key As Rfc2898DeriveBytes = New Rfc2898DeriveBytes(password, salt)

            myAlg.Key = key.GetBytes(myAlg.KeySize / 8 )

            myAlg.IV = key.GetBytes(myAlg.BlockSize / 8 )

 

            Dim buffer As Byte() = Convert.FromBase64String(inString)

 

            Dim memStrm As New MemoryStream()

            Dim memStrmOut As New MemoryStream(buffer)

            Dim encryptor As ICryptoTransform = myAlg.CreateDecryptor

 

            Dim encryptStream As CryptoStream = New CryptoStream(memStrmOut, encryptor, CryptoStreamMode.Read)

 

            Dim reader As New StreamReader(encryptStream)

            DescryText = reader.ReadToEnd

       

        Catch ex As Exception

            DescryText = “”

        End Try

 

        Return DescryText

    End Function

 

    Public Function EncryptString(ByVal inString As String, ByVal password As String, ByVal Mysalt As String) As String

        Dim DescryText As String = “”

        Try

 

            Dim myAlg As RijndaelManaged = New RijndaelManaged()

            Dim salt As Byte() = System.Text.Encoding.ASCII.GetBytes(Mysalt)

            Dim key As Rfc2898DeriveBytes = New Rfc2898DeriveBytes(password, salt)

            myAlg.Key = key.GetBytes(myAlg.KeySize / 8 )

            myAlg.IV = key.GetBytes(myAlg.BlockSize / 8 )

 

            Dim memStrm As New MemoryStream()

            Dim memStrmOut As New MemoryStream()

            Dim encryptor As ICryptoTransform = myAlg.CreateEncryptor

 

            Dim encryptStream As CryptoStream = New CryptoStream(memStrmOut, encryptor, CryptoStreamMode.Write)

 

            Dim writer As New StreamWriter(encryptStream)

            writer.Write(inString)

            writer.Flush()

            encryptStream.FlushFinalBlock()

            memStrmOut.Flush()

 

            DescryText = Convert.ToBase64String(memStrmOut.GetBuffer(), 0, memStrmOut.Length) 

            encryptStream.Close()

        Catch ex As Exception

            DescryText = “”

        End Try

 

        Return DescryText

    End Function

 

    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim a As String = EncryptString(Me.TextBox1.Text, “P@S5w0r]>”, “Proyecto”)

        Response.Cookies(“encryptcookie”).Value = a

    End Sub

 

    Protected Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button2.Click

        Me.TextBox2.Text = DecryptString(Request.Cookies(“encryptcookie”).Value, “P@S5w0r]>”, “Proyecto”)

    End Sub

End Class