Update app.py

app.py

@@ -2,56 +2,55 @@ import streamlit as st
 import random
 import string
 
-# Define vowels and consonants for character substitution
-VOWELS = "aeiou"
-CONSONANTS = "".join(set(string.ascii_lowercase) - set(VOWELS))
-
-# Helper function to generate a random substitution cipher
-def generate_cipher():
-    cipher = {}
-    shuffled_vowels = random.sample(VOWELS, len(VOWELS))
-    shuffled_consonants = random.sample(CONSONANTS, len(CONSONANTS))
-    for v, sv in zip(VOWELS, shuffled_vowels):
-        cipher[v] = sv
-    for c, sc in zip(CONSONANTS, shuffled_consonants):
-        cipher[c] = sc
-    return cipher
-
-# Encrypt text using the substitution cipher
-def encrypt_text(text, cipher):
-    encrypted_text = ""
-    for char in text.lower():
-        if char in cipher:
-            encrypted_text += cipher[char]
+# Helper functions for substitution cipher
+def categorize_letters():
+    vowels = "AEIOUYaeiouy"
+    consonants = "".join([c for c in string.ascii_letters if c not in vowels])
+    return vowels, consonants
+
+def generate_ciphertext(plaintext):
+    vowels, consonants = categorize_letters()
+    symbol_pool = string.ascii_letters + string.digits + string.punctuation
+    cipher_map = {}
+
+    # Create substitution map for each letter in the plaintext
+    for letter in set(plaintext):
+        if letter in vowels:
+            cipher_map[letter] = random.choice([c for c in symbol_pool if c in vowels])
+        elif letter in consonants:
+            cipher_map[letter] = random.choice([c for c in symbol_pool if c in consonants])
         else:
-            encrypted_text += char  # Non-alphabet characters stay the same
-    return encrypted_text
-
-# Generate a helper phrase for decryption
-def generate_helper_phrase(cipher):
-    words = ["hello", "world", "streamlit", "cipher", "decrypt", "help"]
-    helper_text = []
-    for word in words:
-        helper_word = "".join(cipher[char] if char in cipher else char for char in word)
-        helper_text.append(helper_word)
-    return " ".join(helper_text)
-
-# Main Streamlit app
-st.title("Substitution Cipher Encryption/Decryption")
-
-# Input text
-input_text = st.text_input("Enter text to encrypt:")
-
-# Generate cipher and encrypt text
-if input_text:
-    cipher = generate_cipher()
-    encrypted_text = encrypt_text(input_text, cipher)
-    helper_phrase = generate_helper_phrase(cipher)
-
-    # Display results
-    st.write("**Encrypted Text:**", encrypted_text)
-    st.write("**Helper Phrase for Decryption:**", helper_phrase)
-
-    # Display cipher dictionary for testing (optional)
-    if st.checkbox("Show Cipher (for testing purposes)"):
-        st.write(cipher)
+            cipher_map[letter] = letter  # keep spaces and non-alphabetic characters as is
+
+    # Create the encrypted text using the cipher map
+    ciphertext = "".join([cipher_map.get(char, char) for char in plaintext])
+    return ciphertext, cipher_map
+
+def generate_helper_phrase(ciphertext, cipher_map):
+    # Generate a helper phrase that repeats letters from ciphertext
+    helper_words = []
+    for letter in set(ciphertext):
+        if letter.isalpha():
+            word = letter * random.randint(2, 5)  # repeat the letter to give hints
+            helper_words.append(word)
+    return " ".join(helper_words)
+
+# Streamlit App
+st.title("Chiffrement par Substitution")
+st.write("Ce système remplace chaque lettre d'un texte par un caractère aléatoire de la même catégorie (voyelle/consonne).")
+
+# User input
+plaintext = st.text_input("Entrez le texte à chiffrer:", "Exemple de texte")
+
+if st.button("Chiffrer"):
+    ciphertext, cipher_map = generate_ciphertext(plaintext)
+    helper_phrase = generate_helper_phrase(ciphertext, cipher_map)
+
+    # Display the encrypted text and helper phrase
+    st.write("Texte chiffré:")
+    st.code(ciphertext, language="")
+
+    st.write("Phrase d'aide:")
+    st.code(helper_phrase, language="")
+
+    st.write("Note: Utilisez la phrase d'aide pour déduire les correspondances des lettres.")