The steps to encrypt “Hello. How are you?” with paper and pencil

The steps to encrypt “Hello. How are you?” with paper and pencil.

Plaintext Letter      Plaintext Number    +   Key    Result    Subtract26?    Result    Ciphertext Letter
H                            7                              +   13       = 20                               = 20                20 = U
E                             4                              +   13      = 17                               = 17                17 = R
L                             11                           +    13      = 24                               = 24                24 = Y
L                             11                           +    13      = 24                               = 24                24 = Y
O                            14                            +   13      = 27            - 26             = 1                  1 = B

H                           7                              +    13      = 20                               = 20                 20 = U
O                           14                            +    13      = 27            - 26            = 1                    1 = B
W                          22                            +    13      = 35            - 26            = 9                     9 = J

A                          0                               +    13      = 13                              = 13                   13 = N
R                          17                             +    13      = 30            - 26            = 4                      4 = E
E                           4                              +    13      = 17                              = 17                     17 = R

Y                         24                             +    13      = 37             - 26            = 11                     11 = L
O                         14                             +    13      = 27             - 26            = 1                     1 = B
U                         20                             +    13      = 33             - 26            = 7                      7 = H


Comments

Post a Comment

Popular posts from this blog

What is Cryptography? Making Paper Cryptography Tools

Image
What is Cryptography? Making Paper Cryptography Tools Look at the following two pieces of text: The text on the left side is a secret message. The message has been encrypted, or turned into a secret code. It will be completely unreadable to anyone who doesn’t know how to decrypt it (that is, turn it back into the plain English message.) This book will teach you how to encrypt and decrypt messages. The message on the right is just random gibberish with no hidden meaning whatsoever. Encrypting your written messages is one way to keep them secret from other people, even if they get their hands on the encrypted message itself. It will look exactly like random nonsense. Cryptography is the science of using secret codes. A cryptographer is someone who uses and studies secret codes. This book will teach you what you need to know to become a cryptographer. Of course, these secret messages don’t always stay secret. A cryptanalyst is someone who can hack secret codes and read oth
Read more

Making a Paper Cipher Wheel

Image
Before we learn how to program computers to do encryption and decryption for us, let’s learn how to do it ourselves with simple paper tools. It is easy to turn the understandable English text (which is called the plaintext) into the gibberish text that hides a secret code (called the ciphertext). A cipher is a set of rules for converting between plaintext and ciphertext. These rules often use a secret key. We will learn several different ciphers in this book. Let’s learn a cipher called the Caesar cipher. This cipher was used by Julius Caesar two thousand years ago. The good news is that it is simple and easy to learn. The bad news is that because it is so simple, it is also easy for a cryptanalyst to break it. But we can use it as a simple learning exercise. To convert plaintext to ciphertext using the Caesar cipher, we will create something called a cipher wheel (also called a cipher disk). You can either photocopy the cipher wheel that appears in this book,  Cut out the two circle
Read more