Month: January 2012

Lesson Study with Teaching Password Cracking Calculator

I had a much better lesson this week on teaching my students about how password security works, and how to calculate how secure a password is, using Microsoft Excel.  I would like to post more about this soon, but before the details in my memory fade more, this is the basic process I went through, that worked:

  1. Discussion first about how would they hack a password
  2. Go through lower case letter example first
  3. Give pre-filled out handout of Excel
  4. Use partly filled in saved copy to speed up data entry
  5. Have teams come up with a password in the end, and test security with calculator
  6. Possibly next time, we should have a contest within the groups

Starting Excel in Read-Only Mode

We have been using several big spreadsheets almost as databases at my school, because the development time has been so much quicker and more flexible than using a traditional database (although, we will be moving to an SQL solution this coming year.)

The biggest problem at the moment of using a spreadshseet as a database, is the file locking issue of only one user being able to be logged in at a time.  We couldn’t find anything on the Internet, so today I cam up with a batch file hack that solves the problem allowing .  (The ping was added to basically pause the batch file for 10 seconds, so that the file could open before being set to read/write again.)

@echo off
attrib +r spreadsheet.xlsx
start excel spreadsheet.xlsx
ping localhost -n 10
attrib -r spreadsheet.xlsx