RiddleScanner

Overview

In this lesson we will be using a barcode scanner to get riddles from QR codes. Then, we will use a substitution cipher to decrypt the text containing the riddles.

Note: You will need to install this android barcode scanner app before starting this project. Most of you should already have it on your phones. (https://play.google.com/store/apps/details?id=com.google.zxing.client.android&hl=en)

New Concepts

Barcode Scanner:

Add these block components to your code to use the phone's barcode scanner. Note that you will need a barcode scanner installed for this to work.

Let's Get Started:

User Interface Designer:

We will need the following components

• TableLayout(5 columns, 2 rows),
• 10 TextBox in the TableLayout (width=20% each)
• 2 Buttons
• 4 Labels (For Decrypted_Message, and Encrypted_Message: height=20%)
• BarcodeScanner

Note: TextBoxes BeforeX-AfterX should be arranged like this in the TableLayout

Before1   Before2   Before3   Before4   Before5
After1    After2    After3    After4    After5

Logic :

Variables Setup

1. Initialize a variable called message to " ".

ScanButton Setup

1. Call the BarcodeScanner's DoScan

BarcodeScanner Setup

When the BarcodeScanner's AfterScan occurs:

1. Set the Encrypted_Message to the result of the scan.
2. Set the variable message to the result of the scan.

TEST

After scanning a qr code, you should see the Encrypted message from the scan appear.

DecryptButton Setup

When you click the DecryptButton:

1. Set the variable message to the substituted result of the Before and After textboxes, and the message variable.
2. Do this 5 times, for every pair of the substitution boxes.
3. Set the Decrypted_Message text to the variable message.

TEST

Use this key and QR code to test the app.

====Substitution Cipher Key====
7 = i
4 = o
1 = a
8 = w
3 = m
====Encrypted====
7’3 t1ll 8hen 7’3 y4ung 1nd 7’3 sh4rt 8hen 7’3 4ld. 8h1t 13 7?
====Decrypted====
I’m tall when I’m young and I’m short when I’m old. What am I?

The Codes:

Problem One:

``` ====Substitution Cipher Key==== 5 = t 8 = o 4 = n 7 = e 2 = s ``` *** ## Problem Two: ``` ====Substitution Cipher Key==== 9 = a 8 = e 2 = o 1 = r 5 = w ``` *** ## Problem Three: ``` ====Substitution Cipher Key==== b = 5 l = 1 z = 2 m = 7 g = 0 Remember the encrypted characters are on the left and the decrypted characters are on the right. ``` *** ## Problem Four: ``` ====Substitution Cipher Key==== p = 1 q = 2 r = 3 z = , y = . ``` *** ## Problem Five: ``` ====Substitution Cipher Key==== 0 = a 8 = e 2 = t 1 = n 6 = h ``` *** ## Problem Six: ``` ====Substitution Cipher Key==== 8 = a 4 = o 7 = t 2 = e 0 = n ``` *** ## Problem Seven: ``` ====Substitution Cipher Key==== 9 = a 2 = e 4 = i 8 = h 1 = t ``` *** ## Problem Eight: ``` ====Substitution Cipher Key==== 5 = s 4 = t 2 = i 1 = l 9 = e ``` *** ## Problem Nine: ``` ====Substitution Cipher Key==== 9 = e 2 = a 0 = t 8 = u 3 = o ``` *** ## Problem Ten: ``` ====Substitution Cipher Key==== 2 = i 1 = t 9 = e 8 = a 0 = w ``` # External References: # Stretch Goals 1. When the barcode scan finishes have the app speak the encrypted riddle to you. 2. When a decryption of the riddle is complete, have the app speak the decrypted riddle to you.

External References:

1. Barcode Scanner

APK Download