Cryptanalysis of Substitution Ciphers

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Lab Steps

Starting the Cyber Network Security Lab Exercise

Ready for the real environment experience?

Time Limit2h


Monoalphabetic ciphers are simple substitution ciphers where only one alphabet is used to substitute the characters from the plaintext and replace them one-for-one, where each character in the plaintext is always substituted with the same character in the ciphertext. This means that these ciphertexts are susceptible to frequency analysis.

Frequency analysis is a technique where a sample text is analysed to find out how often each character appears, which is used to build a histogram. This becomes the reference guide.

In this lab you will explore this by decrypting a classical cipher, the Caesar cipher.

This lab is part of a series on cyber network security.

Learning Objectives

Upon completion of this lab you will be able to:

  • Show how monoalphabetic ciphers are susceptible to frequency analysis

Intended Audience

This lab is intended for:

  • Cyber and network security specialists


You should possess:

  • A basic understanding of Windows operating system environments
About the Author
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