Create app.py

app.py

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+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]
+        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)