app.py

import streamlit as st
import os
import random
import base64
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC

# --- Sentinel Engine Functions ---

def generate_key(seed: str, dimensions: int = 5):
    """Sentinel multi-dimensional key derivation"""
    kdf = PBKDF2HMAC(
        algorithm=hashes.SHA256(),
        length=32,
        salt=b'sentinel_salt',  # change to a secure static salt or dynamic
        iterations=200000,      # higher iterations for quantum resilience
        backend=default_backend()
    )
    key = kdf.derive(seed.encode())
    # Multi-dimensional expansion (adaptive randomness)
    key += bytes([random.randint(0, 255) for _ in range(dimensions * 16)])
    return key[:32]

def encrypt_data(data: bytes, key: bytes) -> bytes:
    iv = os.urandom(16)  # cryptographically secure IV
    cipher = Cipher(algorithms.AES(key), modes.CBC(iv), backend=default_backend())
    encryptor = cipher.encryptor()

    padding_len = 16 - len(data) % 16
    data += bytes([padding_len] * padding_len)

    encrypted = encryptor.update(data) + encryptor.finalize()
    return iv + encrypted

def decrypt_data(encrypted_data: bytes, key: bytes) -> bytes:
    iv = encrypted_data[:16]
    encrypted_data = encrypted_data[16:]

    cipher = Cipher(algorithms.AES(key), modes.CBC(iv), backend=default_backend())
    decryptor = cipher.decryptor()
    decrypted = decryptor.update(encrypted_data) + decryptor.finalize()

    padding_len = decrypted[-1]
    return decrypted[:-padding_len]

# --- Streamlit UI ---

# Display Logo
st.image(
    "https://huggingface.co/spaces/taarhissian/SentinelCryptography/resolve/main/sentinelcryptography.png",
    caption="SentinelCryptography Logo",
    use_container_width=True
)

st.title("🛡 SentinelCryptography")
st.subheader("A Quantum-Ready Encryption Guardian")
st.write("""
SentinelCryptography is not just an AES tool — it is a living sentinel, designed to protect your messages 
today and withstand the cryptographic challenges of tomorrow.
""")

# --- Session State for Seed ---
if "seed" not in st.session_state:
    st.session_state.seed = ""

# --- Encryption Section ---
st.markdown("---")
st.header("🔒 Encrypt a Message")
message = st.text_area("Enter Message to Encrypt:")
st.session_state.seed = st.text_input("Enter Seed/Password for Key Generation:", st.session_state.seed)

if st.button("Encrypt"):
    if message and st.session_state.seed:
        key = generate_key(st.session_state.seed, dimensions=5)
        encrypted = encrypt_data(message.encode(), key)
        st.success("✅ Encryption Complete!")
        st.code(base64.b64encode(encrypted).decode(), language="text")
    else:
        st.error("Please enter both a message and a seed/password.")

# --- Decryption Section ---
st.markdown("---")
st.header("🔓 Decrypt a Message")
encrypted_input = st.text_area("Enter Encrypted Message (Base64):")

if st.button("Decrypt"):
    if encrypted_input and st.session_state.seed:
        try:
            encrypted_bytes = base64.b64decode(encrypted_input)
            key = generate_key(st.session_state.seed, dimensions=5)
            decrypted = decrypt_data(encrypted_bytes, key)
            st.success("✅ Decryption Complete!")
            st.code(decrypted.decode(), language="text")
        except Exception as e:
            st.error(f"Decryption failed: {e}")
    else:
        st.error("Please enter both an encrypted message and the seed/password.")

# --- Educational & Roadmap Sections ---
st.markdown("---")
st.header("📜 The Legacy of Encryption")
st.write("""
Encryption has evolved from ancient substitution ciphers to mechanical rotors in WWII, 
and finally to AES in the modern era. SentinelCryptography pushes this evolution further, 
preparing for the quantum era.
""")

st.markdown("---")
st.header("🚀 Roadmap for 2025")
st.write("""
1. Q1: Expand post-quantum cryptographic support.  
2. Q2: APIs for web & mobile integration.  
3. Q3: Community challenges to improve security.  
4. Q4: Launch full SentinelCryptography platform with analytics and advanced features.
""")
st.image("https://via.placeholder.com/800x400.png?text=SentinelCryptography+2025+Roadmap")

# --- Donation Section ---
st.markdown("---")
st.header("💖 Support SentinelCryptography")
st.write("""
Your donations help us continue development and keep this project open source.
**Donate via Tether (USDT-ERC20)**: `0xD5255523b1A6a144D9d034c70735b2dB729B49f0`
Every contribution empowers global security for the quantum era.
""")

st.info("SentinelCryptography is open source. Together, we secure the future.")