Frequency Cryptanalysis Tool - Streamlit App

Welcome to our cryptanalysis application for classical ciphers!

Check it out: https://frequency-analysis-crypto-tool.streamlit.app

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This interactive tool was designed to help decrypt texts encrypted with monoalphabetic (Caesar) and polyalphabetic (Vigenère) methods. It applies statistical analysis, including:

• Index of Coincidence (IC),
• Frequency Analysis (Chi²),
• Key Length Detection,
• Automatic Ciphertext Decryption.

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💡 Features

• Graphical interface using Streamlit.
• Supports encrypted text with or without spaces.
• Automatic key detection using Index of Coincidence.
• Smart key reduction to avoid repeated patterns (e.g., "VIGENEREVIGENERE" ➡️ "VIGENERE").
• Clear result display for easy interpretation.

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🧠 How to Use

1. Run the application

streamlit run app.py

2. Input Encrypted Text

Copy/paste your ciphertext into the input area labeled "Enter your encrypted text".

3. Click "Analyze Text"

• The key will be automatically estimated.
• The ciphertext will be decrypted.
• Results will be displayed in the interface.

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🔧 Dependencies

• Python 3.x
• streamlit

Quick install:

pip install streamlit

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💻 Example

Encrypted Text:

GIIVLTKSBZGTUMVINBRXHHVHZAZIPLEMLCKWCIIQZBZEAXUIXPOJSVVVYMYQRWJEBMY...

Expected Output:

Key Found: VIGENERE
Decrypted Text: LACRYPTOGRAPHIEESTLETUDEDESTECHNIQUESPERMETTANTDECHIFFRERDESMESSAGES...

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👥 Team

Project developed by:

• Adjissi Fatima Amina
• Hadi Meriem Lina
• Mellaz Maya Melissa
• Moulai Tinhinane

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⚠️ Notes

• Works best with French texts.
• Accents and punctuation are automatically removed during analysis.

🚀 Coming Soon

• Kasiski test support.
• Graphical representation of letter frequencies.

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Thanks for using our tool!

#crypto #streamlit #vigenere #cesar #frequencyanalysis