How to crack a combination lock?

Project for Coursera's Developing Data Products course

The sequence of numbers, symbols or letters on combination locks may be entered using a single rotating dial which interacts with several discs by using a set of several rotating discs with inscribed numerals which directly interact with the locking mechanism.

Types range from inexpensive three-digit luggage locks to high-security safes.

Unlike a regular padlock, combination locks do not use keys.

For details on different combination locks pls see http://en.wikipedia.org/wiki/Combination_lock.

You have to try in the worst case all possible combinations of the combination lock. The mathematical theory for these permutations with repetitions can be found on http://www.mathsisfun.com/combinatorics/combinations-permutations.html.

An easy number (10 numbers: 0 to 9) combination lock with 3 rings has

10^3

[1] 1000

1000 combinations which was calculated with an R formula.

This slide explains how the number of combinations of a combination lock are calculated with as a Shiny application.

• The application consists of two parts: server.R and ui.R
• server.R creates a server instance which takes two values (the number of symbols on the rotating dial and the number of discs) , computes the number of possible permutations and returns the result
• ui.R creates the html code for a sidepanel containing two text fields that only take numeric values between 1 and 20.
• A button within ui.R triggers server.R to calculate the number of combinations.
• ui.R displays the result returned by server.R in the main panel next to the input fields