rustdi 0.1.0

//! Implementasi kriptografi Multi-Device untuk WhatsApp Web
//!
//! Modul ini mengimplementasikan protokol kriptografi WhatsApp Multi-Device 
//! yang menggunakan sistem enkripsi berbasis Signal Protocol

use crate::errors::*;
use ring::agreement;
use ring::rand::{SystemRandom, SecureRandom};
use ring::{hmac, hkdf, aead};
use untrusted;
use serde::{Deserialize, Serialize};
use std::sync::Arc;

/// Tipe untuk kunci Identity
pub type IdentityKey = [u8; 32];
pub type IdentityKeyPrivate = [u8; 32];

/// Tipe untuk kunci Signed Pre-Key
pub type SignedPreKeyId = u32;
pub type SignedPreKeyPublic = Vec<u8>;
pub type SignedPreKeyPrivate = Vec<u8>;
pub type SignedPreKeySignature = Vec<u8>;

/// Tipe untuk kunci One-Time
pub type OneTimeKeyId = u32;
pub type OneTimeKeyPublic = Vec<u8>;
pub type OneTimeKeyPrivate = Vec<u8>;

/// Pasangan kunci Identity
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct IdentityKeyPair {
    pub public_key: IdentityKey,
    pub private_key: IdentityKeyPrivate,
}

impl IdentityKeyPair {
    /// Menghasilkan pasangan kunci Identity baru
    pub fn generate() -> Result<Self> {
        let mut public_key = [0u8; 32];
        let mut private_key = [0u8; 32];
        
        SystemRandom::new().fill(&mut public_key)
            .map_err(|_| "Failed to generate public key")?;
        SystemRandom::new().fill(&mut private_key)
            .map_err(|_| "Failed to generate private key")?;
            
        Ok(IdentityKeyPair { public_key, private_key })
    }
}

/// Pasangan kunci Signed Pre-Key
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SignedPreKeyPair {
    pub key_id: SignedPreKeyId,
    pub public_key: SignedPreKeyPublic,
    pub private_key: SignedPreKeyPrivate,
    pub signature: SignedPreKeySignature,
    pub timestamp: u64,
}

impl SignedPreKeyPair {
    /// Menghasilkan pasangan kunci Signed Pre-Key baru
    pub fn generate(key_id: SignedPreKeyId) -> Result<Self> {
        let (private_key, public_key) = crate::crypto::generate_keypair()?;
        let mut private_bytes = vec![0u8; private_key.public_key_len()];
        private_key.compute_public_key(&mut private_bytes)?;
        
        // Placeholder untuk signature - dalam implementasi sebenarnya ini akan diisi
        let signature = vec![0u8; 64]; // 64 bytes untuk signature ECDSA
        
        Ok(SignedPreKeyPair {
            key_id,
            public_key,
            private_key: private_bytes,
            signature,
            timestamp: std::time::SystemTime::now()
                .duration_since(std::time::UNIX_EPOCH)
                .unwrap()
                .as_secs(),
        })
    }
}

/// Pasangan kunci One-Time
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct OneTimeKeyPair {
    pub key_id: OneTimeKeyId,
    pub public_key: OneTimeKeyPublic,
    pub private_key: OneTimeKeyPrivate,
}

impl OneTimeKeyPair {
    /// Menghasilkan pasangan kunci One-Time baru
    pub fn generate(key_id: OneTimeKeyId) -> Result<Self> {
        let (private_key, public_key) = crate::crypto::generate_keypair()?;
        let mut private_bytes = vec![0u8; private_key.public_key_len()];
        private_key.compute_public_key(&mut private_bytes)?;
        
        Ok(OneTimeKeyPair {
            key_id,
            public_key,
            private_key: private_bytes,
        })
    }
}

/// Registration ID - identifikasi unik untuk perangkat
pub type RegistrationId = u32;

/// Menghasilkan Registration ID acak
pub fn generate_registration_id() -> RegistrationId {
    let mut rng = SystemRandom::new();
    let mut bytes = [0u8; 4];
    rng.fill(&mut bytes).unwrap();
    u32::from_le_bytes(bytes) & 0x3FFF // Batasi ke 14-bit
}

/// Session Cipher untuk enkripsi pesan individual
pub struct SessionCipher {
    registration_id: RegistrationId,
    identity_key_pair: IdentityKeyPair,
    signed_pre_key_pair: SignedPreKeyPair,
    one_time_keys: std::collections::HashMap<OneTimeKeyId, OneTimeKeyPair>,
}

impl SessionCipher {
    /// Membuat Session Cipher baru
    pub fn new(
        registration_id: RegistrationId,
        identity_key_pair: IdentityKeyPair,
        signed_pre_key_pair: SignedPreKeyPair,
    ) -> Self {
        SessionCipher {
            registration_id,
            identity_key_pair,
            signed_pre_key_pair,
            one_time_keys: std::collections::HashMap::new(),
        }
    }

    /// Menambahkan kunci One-Time baru
    pub fn add_one_time_key(&mut self, key: OneTimeKeyPair) {
        self.one_time_keys.insert(key.key_id, key);
    }

    /// Menghitung kunci ratchet berdasarkan protokol Signal
    pub fn calculate_ratchet_keys(
        &self,
        their_identity_key: &[u8],
        our_base_key: &[u8],
        their_base_key: &[u8],
    ) -> Result<[u8; 64]> {
        let shared_secret = crate::crypto::agree_on_shared_secret(
            agreement::EphemeralPrivateKey::generate(&agreement::X25519, &SystemRandom::new())?,
            their_identity_key
        )?;
        
        let mut key_material = [0u8; 64];
        hkdf::extract_and_expand(
            &hkdf::Salt::new(hkdf::HKDF_SHA256, b"WhisperText"),
            &shared_secret,
            &[],  // Dalam implementasi sebenarnya, info akan berisi informasi ratchet
            &mut key_material
        );
        
        Ok(key_material)
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_identity_key_pair_generation() {
        let identity_key_pair = IdentityKeyPair::generate().unwrap();
        assert_eq!(identity_key_pair.public_key.len(), 32);
        assert_eq!(identity_key_pair.private_key.len(), 32);
    }

    #[test]
    fn test_signed_pre_key_generation() {
        let signed_pre_key = SignedPreKeyPair::generate(1).unwrap();
        assert_eq!(signed_pre_key.key_id, 1);
    }

    #[test]
    fn test_one_time_key_generation() {
        let one_time_key = OneTimeKeyPair::generate(1).unwrap();
        assert_eq!(one_time_key.key_id, 1);
    }

    #[test]
    fn test_registration_id_generation() {
        let reg_id = generate_registration_id();
        assert!(reg_id <= 0x3FFF); // 14-bit maksimum
    }
}