On Tuesday Agents from Web Applications UK went to visit the young recruits of the Stanley Road School for another instalment of their Agent Training.

The recruits at Stanley Road School got to learn all about Cryptography this week, and it looks pretty awesome. The students learned a number of ways to write messages which can be easily encrypted and decrypted (as long as you have the key).

**Shift Cipher**

The students learned to make one letter represent another by shifting the alphabet a set number of places. For example a +4 Alpha -shift would mean a,b,c,d would be written as e,f,g,h. If you wanted to write ‘Meet At Work’ with a +11 Alpha-shift, you would write ‘xppe le hzcv’. It’s kind of like a cryptogram one might see in a Sunday Newspaper, except instead of random letter substitutions , the whole alphabet shifts a set number of places, so as long as you know one correlation of letters (a=f) you can figure the rest out. There’s a fun game the students can use to practice here:

http://cryptoclub.math.uic.edu/shiftcipher/shiftcipher.php

**PigPen Key**

The students learned how to use this key, representing letters wth the shape of the box the letter sits in. A dot in the box indicates it’s the second letter listed, no dot means it’s the first letter. Using the key above, this is how we would decrypt:

In this space you would find WX, there is no dot so it’s the first letter, W

In this space you would find IJ, there is no dot so it is the first letter, I

In this space you would find MN, there is a dot so it is the second letter N

In this space you would find ST, there is a dot so it is the second letter T

In this space you would find EF, there is no dot so it’s the first letter, E

In this space you would find QR, there is a dot so it is the second letter R

**Numbers for Letters**

This one is simpler, if each letter of the alphabet represents a number, what woul 18-20-12-12-4-17 mean? As a note, cryptography and all the other sciency things have a tendency to start counting at 0 instead of 1. Ergo A=0, B=1, C=2 etc.

This week also included a reminder about the binary number system. So, if you wanted to say Meet at 14:00 you could represent the numbers with letters, or you could use the binary numbers taught in previous weeks to represent 1,4,0,0 or 14,00. The previous lesson on Binary can be found