Adventure Island Book Ten
The Mystery of the Invisible Spy
Reading Between The Lines
At last! Emily has been dying to uncover an enemy spy and finally it seems that she has her chance. The strange man with the binoculars is definitely spying on something and she’s pretty sure it’s not the larks nesting on the sand dunes. But, as always in Castle Key, nothing is quite as it seems. There are some big surprises for Scott, Jack, Emily and Drift in The Mystery of the Invisible Spy.
For Emily one of the most exciting parts about this investigation is that she gets to use some secret codes. Emily is an expert on cryptography – that is, the use of codes and ciphers (ten million super-brain points if you know the difference between a code and a cipher. A cipher is where you replace the original message letter by letter, whereas a code is where you replace word by word. People often use the word code to mean both, though).
Codes have been used to communicate secret messages throughout history. One of the most famous examples led to the death of Mary Queen of Scots.
If you remember your Tudor history you’ll know that Elizabeth I kept her cousin Mary Queen of Scots under house arrest for many years. Mary’s supporters believed she should rightfully be on the throne of England, and they sent coded letters to her, discussing a plot to overthrow Elizabeth. But the letters were intercepted by Elizabeth’s spymaster - with the help of a carefully placed double agent or two. The code was soon cracked, the plot was discovered, and Mary was beheaded.
a snippet of the message sent by Mary Queen of Scots – can you decipher it using the key?
Mary’s code was quite easy to crack (even if you didn’t have the key on the same page!) because was each letter was replaced by a symbol. The codebreakers could look at the text and see which symbol came up the most often – they knew that almost certainly represented the letter E, which is the most frequently used in English. With a bit of effort you can soon crack the whole code using this kind of ‘frequency analysis.’ Elizabeth’s spies certainly did.
Another problem with messages like this is that they are obviously in code so they immediately attract attention. If you came across a message that looked like this, GRDE XNY PZYIG you might not be able to read it, but you’d know that someone was UP TO SOMETHING and sending TOP SECRET INFORMATION (either that, or they were trying to type while eating a hot dog and watching a really exciting Cup Final match!)
One way round this problem is to use steganography rather than cryptography. Steganography means concealed writing. You conceal your secret message within something perfectly innocent-looking – like a shopping list. Then, if it falls into enemy hands, they have no reason to be suspicious. If Mary had disguised her messages as orders to her dressmaker for some new gloves, for example, she might not have met her terrible fate.
So, how do you conceal a message? The Ancient Greeks apparently tattooed messages onto the shaved heads of messengers, who then let their hair grow back to conceal the words! Or you can use invisible ink to write between the lines of a ‘cover text’ (if you’ve ever heard the phrase ‘reading between the lines’ you now know where it comes from).
the problem with invisible ink is that you can’t see what you’re writing, so it’s easy to make mistakes – can you spot the letter I’ve missed?
But these days, steganography is more often used to send coded messages over computer networks, where information can easily be hidden large data files, such as ordinary looking digital photographs.
Do you know of any other kinds of code? How about devising your own code and sending some messages to your friends?
Question 10: Go back to the message in code used by Mary Queen of Scots and decipher it using the given key. Where does Mary want her supporters to meet her?
Top tip! In the Tudor alphabet the letters "u" and "v" were the same letters.
In the field (I)
On the beach (N)
And that’s it! You should now have all ten letters you need to reveal the culprit and enter the competition to star in the next Adventure Island book.
You will need to unscramble your letters to crack the mystery.
So, whodunnit? Was it:
BRIAN T. FRYE
RYAN B. FEARN?
(If you want more information about the mystery and the suspects you will find it all here:
Email: email@example.com with the subject line ‘OPERATION DIAMOND’ and the name of the thief in the email, along with your name, age and address.
Even if you haven't started the treasure hunt yet, there's still time to go back and find the clues because the closing date for entries isn't until July 23rd, 2012!
These are the direct links to the blog posts
1. GUARDIAN CHILDREN’S BOOKS
3. THE BOOKBAG
9. ORION BOOKS
10. HELEN MOSS
This competition ends on Monday 23 July 2012 and is open only to entrants in the UK and Eire.