Ella Schwartz - Can You Crack the Code?: A Fascinating History of Ciphers and Cryptography

BLOOMSBURY CHILDRENS BOOKS

Bloomsbury Publishing Inc., part of Bloomsbury Publishing Plc

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This electronic edition published in 2019 by Bloomsbury Publishing Plc

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First published in the United States of America in March 2019 by Bloomsbury Childrens Books

Text copyright 2019 by Ella Schwartz

Illustrations copyright 2019 by Lily Williams

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Library of Congress Cataloging-in-Publication Data

Names: Schwartz, Ella, author.

Title: Can you crack the code? / by Ella Schwartz.

Description: New York : Bloomsbury, [2019]

Identifiers: LCCN 2018011662 (print) LCCN 2018020549 (e-book)

ISBN 978-1-6811-9514-8 (HB)
ISBN 978-1-6811-9989-4 (eBook)

Subjects: LCSH: CiphersJuvenile literature. | CiphersHistoryJuvenile literature. |

CryptographyJuvenile literature. | CryptographyHistoryJuvenile literature.

Classification: LCC Z103.3 .S378 2019 (print) | LCC Z103.3 (e-book) | DDC 652/.8dc23

LC record available at https://lccn.loc.gov/2018011662

Book design by Danielle Ceccolini

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For Jeff, who cracked the code to my heart

CONTENTS

CAN YOU CRACK THE CODE?

There are codes all around you, designed to keep secrets safe or keep you out of places you dont belong. Some codes are designed to keep a computer system safe from hackers. Other codes are designed to keep secrets safe from prying eyes.

Can you crack the code?

When we talk about cracking the code, what do we really mean? Breaking into something? Discovering a hidden message? Hacking into something you probably were never supposed to see?

Yes to all that!

Cracking the code means revealing a secret.

A secret is only a secret as long as it doesnt fall into the wrong hands. The minute a secret is exposed, it stops being a secret. Then its just informationinformation that was never meant to be revealed. There are many reasons someone may not want to reveal this information. It could spoil a special surprise, it might be embarrassing, or it could be very damaging.

Whatever the reason for having a secret, the goal is: keep the secret safe!

So, can you crack the code? Can you uncover the secret? The codemaker sure hopes not. Theyve gone to a lot of trouble to keep the secret safe.

This begins the battle between codemakers and codebreakers. Since ancient history, codemakers have worked very hard to build the strongest codes to protect their most important secrets, but codebreakers keep finding more powerful methods for cracking those codes. As the codemakers get more sophisticated, so do the codebreakers.

This book will teach you all about cryptography, encryption, hacking, and cybersecurity. All of that is pretty cool, but theres more! This book is more than meets the eye. Its not just a book. Its actually one big secret for you to crack. Read it carefully. Only the smartest codebreakers will spot all the clues in this book to crack the code and unlock the secret.

Will you crack the code?

Lets find out.

A TALE OF CODES AND CIPHERS

Keeping Secrets Safe

Secrets are important.

Keeping a secret safe is just as important.

One way someone might choose to protect a secret is by pretending there is no secret. If someone doesnt suspect you have a secret they are not going to go snooping. This is the idea behind the ancient practice of steganography. Steganography is a type of communication where a message is kept hidden. The word steganography comes from two Greek words: steganos, which means covered, and graphein, which means to write. Covered writing. In other words, hidden secrets.

Steganography has been used throughout history. When the ancient Chinese wanted to send a secret message, they wrote the message on silk, scrunched the silk into a tight ball, then covered the ball in wax. The messenger would then swallow the ball of wax. To deliver the message, you can imagine what the messenger had to do nextyuck.

The ancient Greeks also used steganography to keep their messages hidden. One technique they used was shaving a messengers head, tattooing a message on his scalp, and waiting for the hair to grow back before sending the messenger to the destination. Obviously, the message couldnt have been all that urgent!

Steganography is even used today by secret agents around the world. The tool? Invisible ink. A secret agent uses a special kind of ink to write a message. When the ink dries, it becomes invisible. The recipient would need to know that to reveal the hidden words, they would have to heat the ink until the message reappears.

Secret agents can also hide a message in what, at first glance, may appear like a boring note. But if the recipient knows what to look for, a secret might be revealed. Take a look at the sentences below:

Cole rises and cooks kale. Then he eats. Cole only drinks espresso.

Simple enough? Nothing sneaky going on, right?

If the recipient of the message knows what to look for, though, they can find a secret message hidden in that text. Notice the first letters of each of the words:

C ole r ises a nd c ooks k ale. T hen h e e ats. C ole o nly d rinks e spresso.

Now put all these letters together to form the secret message:

Crack the code

This isnt the only way to use steganography to hide a secret message in plain sight. Take a look at the block of characters below:

On first glance, the text above appears like a random string of letters and numbers, but if you look carefully, youll notice words: JUNGLE, LIBRARY, HOME, MATH, MARCH, and others. Is there a secret message hidden here? You bet there is! But how to decode it? For that youll need a special decoder.