.NET (Core and Framework)

    Private Sub decryptBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles decryptBtn.Click

        Try

            Dim deRecData As String
            ' Dim decTripDe As New TripleDES
            Dim decData As New TripleDES


            LoadData()
            ' Configure and execute the command.
            cmd = New System.Data.SqlClient.SqlCommand("SELECT * FROM Lab where patient_Id = @Pat_ID")
            cmd.Connection = cn
            Dim paraPatId As SqlParameter = cmd.Parameters.Add("@Pat_ID", txtEncryptedBytes.Text)
            ' Load the DataTable.
            datadapt = New System.Data.SqlClient.SqlDataAdapter(cmd)
            ds = New DataSet
            datadapt.Fill(ds)
            ds.Tables.Add(dt)
            'datGrid.DataSource = ds.Tables(0)
            cn.Close()

            'Dim dt As DataTable
            'Dim dc As DataColumn
            Dim dRow As DataRow
            dRow = dt.NewRow
            For Each dRow In ds.Tables("Lab").Rows
                decData = New TripleDES()
                deRecData = decData.Decrypt(dt.Rows(0)("Test_type"))' -->error here, null reference
                dt.Rows.Add(deRecData)
                ds.Tables.Add(dt)
                MsgBox("what is that")
            Next
            datGrid.DataSource = ds.Tables(0)

        Catch ex As SqlException
            MsgBox(ex.Message.ToString())
        Finally

        End Try
    End Sub







Public Function Decrypt(ByVal inputInBytes() As Byte) As String
        ' UTFEncoding is used to transform the decrypted Byte Array
        ' information back into a string.
        Dim utf8encoder As UTF8Encoding = New UTF8Encoding()
        Dim tdesProvider As TripleDESCryptoServiceProvider = New TripleDESCryptoServiceProvider()

        ' As before we must provide the encryption/decryption key along with
        ' the init vector.
        Dim cryptoTransform As ICryptoTransform = tdesProvider.CreateDecryptor(Me.key, Me.iv)

        ' Provide a memory stream to decrypt information into
        Dim decryptedStream As MemoryStream = New MemoryStream()
        Dim cryptStream As CryptoStream = New CryptoStream(decryptedStream, cryptoTransform, CryptoStreamMode.Write)
        cryptStream.Write(inputInBytes, 0, inputInBytes.Length)
        cryptStream.FlushFinalBlock()
        decryptedStream.Position = 0

        ' Read the memory stream and convert it back into a string
        Dim result(decryptedStream.Length - 1) As Byte
        decryptedStream.Read(result, 0, decryptedStream.Length)
        cryptStream.Close()
        Dim myutf As UTF8Encoding = New UTF8Encoding()
        Return myutf.GetString(result, 0, decryptedStream.Length)
    End Function
End Class       

password protected