Inicio de sesion con clave encriptada SQL VB.NET

Crear un inicio de sesion con clave de usuario encriptada en una base de datos Sql desde Vb.net

En el form1:

• ComboBox1
• TextBox1
• Button1
• Label1
• Label2

Diseño del formulario

Codigo

Imports System.ComponentModel

Imports System.Data

Imports System.Data.OleDb

Imports System.Data.SqlClient

Imports System.Text

Imports System.Security.Cryptography

Public Class Form1

    Dim SQL As String

    Dim SERVIDOR As String = "NOMBRE DEL SERVIDOR"

    Dim BD As String = "BASE DE DATOS"

    Dim USUARIO As String = "USUSRIO"

    Dim CONTRASEÑA As String = "CLAVE"

    Dim VALIDAR_USUARIO As String

    Public CONEXION As New SqlConnection("Data Source=" & SERVIDOR & ";" &

                                     "Initial Catalog=" & BD & ";" &

                                     "User Id=" & USUARIO & ";Password=" & CONTRASEÑA & "")

    Sub FormatoTexto()

        TextBox1.BackColor = Color.Azure

        ComboBox1.BackColor = Color.Azure

        ComboBox1.ForeColor = Color.Teal

        TextBox1.ForeColor = Color.Teal

    End Sub

    Public Function Desencriptar(ByVal Input As String) As String

        Dim IV() As Byte = ASCIIEncoding.ASCII.GetBytes("qualityi")

        Dim EncryptionKey() As Byte = Convert.FromBase64String("rpaSPvIvVLlrcmtzPU9/c67Gkj7yL1S5") 'No se puede alterar la cantidad de caracteres pero si la clave

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

        Dim des As TripleDESCryptoServiceProvider = New TripleDESCryptoServiceProvider

        des.Key = EncryptionKey

        des.IV = IV

        Return Encoding.UTF8.GetString(des.CreateDecryptor().TransformFinalBlock(buffer, 0, buffer.Length()))

    End Function

    Public Function Encriptar(ByVal Input As String) As String

        Dim IV() As Byte = ASCIIEncoding.ASCII.GetBytes("qualityi")

        Dim EncryptionKey() As Byte = Convert.FromBase64String("rpaSPvIvVLlrcmtzPU9/c67Gkj7yL1S5") 'No se puede alterar la cantidad de caracteres pero si la clave

        Dim buffer() As Byte = Encoding.UTF8.GetBytes(Input)

        Dim des As TripleDESCryptoServiceProvider = New TripleDESCryptoServiceProvider

        des.Key = EncryptionKey

        des.IV = IV

        Return Convert.ToBase64String(des.CreateEncryptor().TransformFinalBlock(buffer, 0, buffer.Length()))

    End Function

    Private Sub getData(ByVal dataCollection As AutoCompleteStringCollection)

        Dim command As SqlCommand

        Dim adapter As New SqlDataAdapter()

        Dim DataSet As New DataSet()

        SQL = "SELECT DISTINCT [USUARIO] FROM [USUARIO]"

        Try

            CONEXION.Open()

            command = New SqlCommand(SQL, CONEXION)

            adapter.SelectCommand = command

            adapter.Fill(DataSet)

            adapter.Dispose()

            command.Dispose()

            CONEXION.Close()

            For Each row As DataRow In DataSet.Tables(0).Rows

                dataCollection.Add(row(0).ToString())

            Next

        Catch ex As Exception

            MessageBox.Show(ex.Message)

        End Try

    End Sub

    Sub Verificacion()

        Dim verificado As String = ComboBox1.Text & TextBox1.Text

        Dim Comando As New SqlCommand("SELECT * FROM USUARIO WHERE USUARIO =  '" & ComboBox1.Text & "' AND CLAVE =  '" & Encriptar(TextBox1.Text) & "'", CONEXION)

        ' crear DataReader

        Dim DataReader As SqlDataReader

        CONEXION.Open()

        DataReader = Comando.ExecuteReader() ' obtener DataReader

        ' recorrer filas

        While DataReader.Read()

            VALIDAR_USUARIO = DataReader("USUARIO") & "" & Desencriptar(DataReader("CLAVE"))

        End While

        DataReader.Close()

        CONEXION.Close()

        If verificado = VALIDAR_USUARIO Then

            Form2.Show()

            Me.Hide()

            'limpiar las cajas de texto

            TextBox1.Text = ""

            ComboBox1.Text = ""

        Else

            TextBox1.BackColor = Color.Beige

            ComboBox1.BackColor = Color.Beige

            ComboBox1.ForeColor = Color.DarkSalmon

            TextBox1.ForeColor = Color.DarkSalmon

            MsgBox("Contraseña y/o usuario incorrecta", MsgBoxStyle.Information + MsgBoxStyle.OkOnly, "Validación")

        End If

    End Sub

    Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged

        Call FormatoTexto()

    End Sub

    Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged

        Call FormatoTexto()

    End Sub

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        Call FormatoTexto()

        ComboBox1.Select()

        ComboBox1.AutoCompleteMode = AutoCompleteMode.Append

        ComboBox1.AutoCompleteSource = AutoCompleteSource.CustomSource

        Dim combData As New AutoCompleteStringCollection()

        getData(combData)

        ComboBox1.AutoCompleteCustomSource = combData

    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

        Call Verificacion()

    End Sub

End Class