Non-letters pass through unchanged and do not consume keyword letters. The keyword repeats as needed.
Frequently asked questions
How does the Vigenere cipher work?
Each letter of your text is shifted by the matching letter of the keyword (A=0, B=1, and so on), with the keyword repeating. ATTACKATDAWN with key LEMON gives LXFOPVEFRNHR.
Is it secure?
It resisted breaking for 300 years, but modern analysis cracks short keys easily. Use it for puzzles and learning, not real secrets.
Do spaces consume keyword letters?
No. Only letters are encrypted and only letters advance the keyword, so spacing never throws the alignment off.
Preview
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