With this tool, you can:
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Encode text files using the Vigenere cipher with a keyword you choose
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Decode already encoded text, providing a keyword
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Attempt to break the cipher, guessing the keyword length first and then the most likely keywords. The index of coincidence and a chi-squared test are used, with pretty good results!
The program will guide you with a step-by-step menu.
Compilation is extremely straightforward:
gcc -o vigenere main.c Vigenere.c
Remember to save the prob-en.txt
file in the same folder as the executable.