Pregunta 2 Final POO-I

Imports System.Security.Cryptography
Imports System.IO
Imports System.IO.IsolatedStorage

Public Class Form1

    Dim ue As New System.Text.UTF8Encoding
    Dim sec As New RSACryptoServiceProvider

    Dim bytString() As Byte, bytCifrado() As Byte, bytDescifrado() As Byte

    Dim ISF As IsolatedStorage = IsolatedStorageFile.GetuserStoreForAssembly


    Sub cifrado(texto As String)
        bytString = ue.GetBytes(texto)
        bytCifrado = sec.Encrypt(bytString, False)
        txtCifrado.Text = Convert.ToBase64String(bytCifrado)
    End Sub

    Private Sub btnCifrar_Click(sender As Object, e As EventArgs) Handles btnCifrar.Click
        Call cifrado(txtTexto.Text)
    End Sub

    Private Sub btnGrabar_Click(sender As Object, e As EventArgs) Handles btnGrabar.Click
        Dim nombre$ = InputBox("Ingrese en nombre del archivo")
        Using fs As New IsolatedStorageFileStream(nombre, FileMode.Create, ISF)
            Using sw As New StreamWriter(fs)
                sw.Write(txtCifrado.Text)
            End Using
        End Using
    End Sub

    Private Sub btnAbrir_Click(sender As Object, e As EventArgs) Handles btnAbrir.Click
        Dim nombre$ = InputBox("Ingrese en nombre del archivo a abrir")
        Dim texto$ = ""
        Using fs As New IsolatedStorageFileStream(nombre, FileMode.Open, ISF)
            texto = New StreamReader(fs).ReadToEnd
            descifrado(texto)
        End Using
    End Sub

    Sub descifrado(texto As String)
        bytDescifrado = sec.Decrypt(Convert.FromBase64String(texto), False)
        txtCifrado.Text = ue.GetString(bytDescifrado)
    End Sub

End Class