Topic 1
Common Ciphers
Cryptography is about making plain text into unintelligible text and has been in existence since the development of hieroglyphics, around 3000 B.C.E. Select one of the following ciphers and explain how it works. Provide an example of how the cipher works.
- Atbash cipher (around 500 B.C.E.)
- Scytale cipher (around 400 B.C.E.)
- Caesar cipher (around 200 B.C.E.)
- Vigenere cipher (around 1500 C.E.)
Topic 2
Kerchoff’s Cipher Principles
In 1883, Auguste Kerchoff wrote two journal articles on the military use of cryptography in which he stated six design principles. Select one of the six design principles listed below and explain how it works, providing an example:
- The system must be practically, if not mathematically, indecipherable.
- It must not be required to be secret, and it must be able to fall into the hands of the enemy without inconvenience.
- Its key must be communicable and retainable without the help of written notes, and changeable or modifiable at the will of the correspondents.
- It must be applicable to telegraphic correspondence.
- It must be portable, and its usage and function must not require the concourse of several people.
- It is necessary, given commands of its application, that the system be easy to use, requiring neither mental strain nor the knowledge of a long series of rules to observe.
