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Issue 19.3 ('Black Hole')
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Holy Cryptography, Batman!

Introduction to Cryptography with the Caesar Cipher

Issue: 19.3 (May/June 2021)
Author: Eugene Dakin
Author Bio: Eugene works as a Senior Oilfield Technical Specialist. He has university degrees in the disciplines of Engineering, Chemistry, Biology, Business, and a Ph.D. in Chemical Engineering. He is the author of dozens of books on Xojo available on the xdevlibrary.com website.
Article Description: No description available.
Article Length (in bytes): 16,440
Starting Page Number: 52
Article Number: 19306
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Download Icon project19306.zip Updated: 2021-05-02 22:26:20

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Excerpt of article text...

If you wanted to send a secret message to another in school, you could use cryptography to make the message difficult to read if someone had access to you message and was not the intended audience. A loose definition of cryptography is to protect secret messages, as is commonly performed by the military.

Some of the terms are to encrypt a message, which means to scramble it in an orderly way. Decryption takes the scrambled text and then puts the message in its original form to allow the user to understand the message. The reason for using encryption is to protect confidential messages that could be intercepted when traveling to the final person. The term cipher is used when writing code in a programming language that encodes a message. Cryptography usually doesn't change the size of the string or file, and may increase the size which depends on the type of cryptography being used.

Today's Caesar Cipher is easy to use and easy to implement. Although I recommend other more difficult ciphers for real-world applications, it is much better to implement any cipher than no cipher at all. Searching for programs that store personal information in plain text is trivial—it's a serious beginner error to do that in your projects and shouldn't happen. This article is a good starting point to understand the fundamentals of encoding and decoding.

One of the most famous methods of encryption was with Julius Caesar, the Roman who lived a few thousand years ago, and is a simple letter-substitution cipher. The Caesar Cipher was named after him and is an easy concept to grasp.

You just take a message (such as "Hello World") and then replace each letter with the next letter in the alphabet that is four letters away. Figure 1 is a cipher ring that is used to change the letters.

Letters of the message are shifted to the right by four, which means that the capital letter H is written as the letter L, O is converted to an S, and so on. Figure 2 shows the original message and the encrypted message.

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