Exercises

Longhand Recursive Fib.

Vigenere Cipher

Problem Descripton

The Caeser Cipher was one of man's first text encryption methods. A numeric key is used to represent how many alphabetic rotations should be applied to each character of a text. A key of two means all As become Cs, all Bs become Ds, etc. The Vigenere Cipher takes a keyword instead of a numeric key. Each letter of the keyword is treated as a shift value. In other words, the shift value used for a letter is equal to its index value in the alphabet. This means that the letters 'a'-'z' (and 'A'-'Z') are equivalent to the numbers 0-25. The keyword is repeated as necessary to apply a shift letter to each character of the text.

Create a Caeser's cipher. Use it to create a Vigenere Cipher. Only letters should be changed, maintaining their case. Other characters should remain unchanged.

Solving the Problem

*The blue comments below are examples of the approach.

Vigenere Solution Vigenere Solution

Longhand Recursive Fib.