Communicate | Keep Your Messages Secret

How to stop your messages being read by spies!

Contents

Part 1 | Learn About Encryption

What is encryption?

What is the Caesar Cypher?

Part 2 | Activity

Scenario

The Key

Print Out

Part 3 | The Bad Jokes!

Part 4 | Badges

Skills

Communicator

About This Page

Part 1 | Learn About Encryption ⭱

What is encryption? ⭱

Encryption

"encryption" means to jumble a message up so that only you and your friend can read it.

For example, when you visit a secure website, your computer and the website computer encrypt all messages between them (including credit card data) so that no one else can intercept and read those messages.

For example, when spies send secrets, they use encryption, so that their enemies cannot read their messages.

Decryption

"decryption" is the reverse process, to un-jumble the message.

The message is known as the "plaintext".

Key

The procedure for encryption and decryption uses a "key" (such as a "password") to do the jumbling and un-jumbling.

Without the key, the message cannot be read.

Only you and your friend should know the key. You use the key to encrypt the message, and your friend uses it to decrypt the message.

We will look at the simplest method for encryption : the Caesar Cypher.

What is the Caesar Cypher? ⭱

2000 years ago, Roman emperor Julius Caesar first used encryption to send important messages to his armies.

He jumbled the message, by swapping each letter with another letter.

He would share what the "letter swaps" were with his army leaders.

Key

Here is an example key:-

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
| | | | | | | | | | | | | | | | | | | | | | | | | |
S N O G H V A U W R B K Y T I Z Q C X F L M D J E P

Plaintext

Here is some plaintext:-

SEND MY MAIN ARMY TO DEFEND ROME, BUT SECRETLY SEND A SEPARATE ARMY TO THE HILS BEHIND ROME FOR A SURPRISE ATTACK ON THE ENEMY FROM BEHIND.

Encryption

Here is what the message might look like if we substitute the letters above (A for S, B for N etc):-

XHTG YE YSWT SCYE FI GHVHTG CIYH, NLF XHOCHFKE XHTG S XHZSCSFH SCYE FI FUH UWKX NHUWTG CIYH VIC S XLCZCWXH SFFSOB IT FUH HTHYE VCIY NHUWTG.

Now let's have a go with the activity!

Part 2 | Activity ⭱

Scenario ⭱

I am Batman's arch enemy: the Really Bad Joker!

I use really bad jokes to kill my enemies!

You are a hacker working for Batman.

You have hacked into my computers and found my encrypted jokes and the key to unlocking them.

You must decrypt the Jokes and read them out to me in our Zoom meeting to get revenge on me.

As it was Halloween recently, the jokes have a ghostly theme!

The Key ⭱

The key you have recovered from my computer is:-

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
| | | | | | | | | | | | | | | | | | | | | | | | | |
S P U K N V D A E X Y O T R H L B C Z W Q G F J M I

Print Out ⭱

If you want something to print out, you can use the PDF here:-

Worksheet

Part 3 | The Bad Jokes! ⭱

15 Points

Joke 01 | A ghost's holiday ⭱

Question

TOHM GL VOLAMA IHM ZE MOI ACYYIN?

ZRI ARNIHY!

Answer

What do ghosts eat in the summer?

[Ice scream!]

Joke 02 | Dead Letters ⭱

Question

OLT GL GIHG BILBPI AIEG PIMMINA?

MOIK CAI MOI VOLAM LWWZRI!

Answer

How do dead people send letters?

[They use the ghost office!]

Joke 03 | Pasta Its Best ⭱

Question

TOHM GL ZMHPZHE VOLAMA PZDI ML IHM?

ABLLDVIMMZ!

Answer

What do Italian ghosts like to eat?

[Spookgetti!]

Joke 04 | Up and down ⭱

Question

TOHM GL GIHG BILBPI NZGI HM MOIYI BHNDA?

NLPPIN-VOLAMINA!

Answer

What do dead people ride at theme parks?

[Roller-ghosters!]

Joke 05 | Bail out or crease up ⭱

Question

TOHM GLIA GNHRCPH BPHK RNZRDIM TZMO?

H FHYBZNI QHM!

Answer

What does Dracula play cricket with?

[A vampire bat!]

Joke 06 | Monkeying Around ⭱

Question

TOHM ZA H VOLAM'A WHFLCNZMI WNCZM?

QLL-EHEHA!

Answer

What is a ghost's favourite fruit?

[Boo-nanas!]

Joke 07 | Goulympic Games ⭱

Question

TOHM VHYI GL VOLAMA PZDI ML BPHK?

OZGI-HEG-AONZID!

Answer

What game do ghosts like to play?

[Hide-and-shriek!]

Joke 08 | Its not stawberry ⭱

Question

TOHM ZA H FHYBZNI’A WHFLCNZMI ZRI RNIHY?

FIZE-ZPPH!

Answer

What is a vampire’s favourite ice cream?

[Vein-illa!]

Joke 09 | Don't Kick Off ⭱

Question

TOHM ZA H VOLAM'A QIAM WLLMQHPP BLAZMZLE?

VOLCP-DIIBIN!

Answer

What is a ghost's best football position?

[Ghoul-keeper!]

Joke 10 | Hair Raising ⭱

Question

TOHM GL VOLAMA BCM LE MOIZN OHZN?

ARHNI-ABNHK!

Answer

What do ghosts put on their hair?

[Scare-spray!]

Joke 11 | Witch Doctor ⭱

Question

TOK GZG MOI TZMRO VL ML MOI GLRMLN?

AOI OHG H GZSSK ABIPP!

Answer

Why did the witch go to the doctor?

[She had a dizzy spell!]

Joke 12 | Ghost Orchestra ⭱

Question

TOHM ZA H ADIPIMLE'A WHFLCNZMI YCAZRHP ZEAMNCYIEM?

MOI MNLY-QLEI!

Answer

What is a skeleton's favourite musical instrument?

[The trom-bone!]

Joke 13 | Spooky Shopping ⭱

Question

TOINI GL WHAOZLEHQPI VOLAMA AOLB?

QLLMZUCIA!

Answer

Where do fashionable ghosts shop?

[Bootiques!]

Joke 14 | Spook Seat Driver ⭱

Question

OLT GLIA WNHEDIEAMIZE VIM HNLCEG MLTE?

H YLEAMIN MNCRD!

Answer

How does Frankenstein get around town?

[A monster truck!]

Joke 15 | Fearful Future ⭱

Question

OLT GL YLEAMINA MIPP MOIZN WCMCNI?

MOIK NIHG MOIZN OLNNLN-ARLBI!

Answer

How do monsters tell their future?

[They read their horror-scope!]

Joke 16 | Out of cluck ⭱

Question

TOHM GL KLC RHPP H VOLAM ROZRDIE?

H BLCPMNK-VIZAM!

Answer

What do you call a ghost chicken?

[A poultry-geist!]

Joke 17 | Sunday Lurch ⭱

Question

TOHM GL VOLAMA BCM LE MOIZN MCNDIK?

VNHFI-K!

Answer

What do ghosts put on their turkey?

[Grave-y!]

Joke 18 | Open and shut ⭱

Question

TOHM DZEG LW DIK GLIA H VOLAM CAI?

H ABLLD-IK!

Answer

What kind of key does a ghost use?

[A spook-ey!]

Joke 19 | Don't look now ⭱

Question

TOHM GL KLC GL ZW H SLYQZI NLPPA MOIZN IKIA HM KLC?

BZRD MOIY CB HEG VZFI MOIY QHRD!

Answer

What do you do if a zombie rolls their eyes at you?

[Pick them up and give them back!]

Joke 20 | Time to Rise ⭱

Question

TOIE GLIA H VOLAM IHM QNIHDWHAM?

ZE MOI YLHEZEV!

Answer

When does a ghost eat breakfast?

[In the moaning!]

Joke 21 | Your Last Meal ⭱

Question

TOHM GL ADIPIMLEA AHK QIWLNI MOIK QIVZE GZEZEV?

"QLEI HBBIMZM!"

Answer

What do skeletons say before they begin dining?

["Bone appetit!"]

Joke 22 | In-die-gestion ⭱

Question

TOHM OHBBIEA ZW H YLEAMIN IHMA MLL YHEK OLCAIA?

OI VIMA OLYIAZRD!

Answer

What happens if a monster eats too many houses?

[He gets homesick!]

Part 4 | Badges ⭱

Skills ⭱

Skills Challenge Award

5: Take part in at least two problem solving activities that you haven’t done before. It should be something that you need to think creatively for. As part of the activity you need to say what you found difficult, what you did to solve the problem, and why.

Communicator ⭱

World Badge

5f Write three simple messages using codes, ciphers, invisible ink or semaphore. Try to work out three similar messages given to you.

About this page

Author

This page was created by Julian Turner, Section Assistant Leader, Falcon Pack, 1st Ripley Scouts, Derbyshire, UK.

Related Links

Webside | 1st Ripley E-Cubs Home Page.

Website | 1st Ripley Scouts Home Page.

Facebook | 1st Ripley