trustformers-mobile 0.1.1

//! Cryptographic protocols and configurations
//!
//! This module implements advanced cryptographic protocols including homomorphic
//! encryption, secure multi-party computation, zero-knowledge proofs, and digital
//! signature schemes for secure federated learning.

use serde::{Deserialize, Serialize};
use crate::federated_learning_v2_backup::types::*;
use trustformers_core::{Result, CoreError};

/// Cryptographic configuration for secure protocols
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CryptographicConfig {
    /// Secure aggregation protocol
    pub aggregation_protocol: SecureAggregationProtocol,
    /// Homomorphic encryption settings
    pub homomorphic_encryption: HomomorphicEncryptionConfig,
    /// Secure multi-party computation
    pub secure_mpc: SecureMPCConfig,
    /// Digital signature scheme
    pub signature_scheme: DigitalSignatureScheme,
    /// Key exchange protocol
    pub key_exchange: KeyExchangeProtocol,
    /// Zero-knowledge proofs
    pub zero_knowledge_proofs: ZKProofConfig,
}

/// Homomorphic encryption configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct HomomorphicEncryptionConfig {
    /// Encryption scheme
    pub scheme: HomomorphicScheme,
    /// Security level (bits)
    pub security_level: u16,
    /// Polynomial modulus degree
    pub poly_modulus_degree: u32,
    /// Coefficient modulus
    pub coeff_modulus: Vec<u64>,
    /// Plaintext modulus
    pub plaintext_modulus: u64,
    /// Optimization level
    pub optimization_level: OptimizationLevel,
}

/// Secure multi-party computation configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SecureMPCConfig {
    /// MPC protocol
    pub protocol: MPCProtocol,
    /// Number of parties
    pub num_parties: u32,
    /// Threshold for secret sharing
    pub threshold: u32,
    /// Security parameter
    pub security_parameter: u16,
    /// Communication rounds
    pub communication_rounds: u32,
}

/// Zero-knowledge proof configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ZKProofConfig {
    /// Proof system
    pub proof_system: ZKProofSystem,
    /// Circuit complexity
    pub circuit_complexity: u32,
    /// Proof size optimization
    pub proof_size_optimization: bool,
    /// Verification key caching
    pub verification_key_caching: bool,
}

/// Homomorphic encryption manager
#[derive(Debug)]
pub struct HomomorphicEncryptionManager {
    config: HomomorphicEncryptionConfig,
    public_key: Option<Vec<u8>>,
    private_key: Option<Vec<u8>>,
    evaluation_keys: Option<Vec<u8>>,
}

impl HomomorphicEncryptionManager {
    /// Create a new homomorphic encryption manager
    pub fn new(config: HomomorphicEncryptionConfig) -> Result<Self> {
        Ok(Self {
            config,
            public_key: None,
            private_key: None,
            evaluation_keys: None,
        })
    }

    /// Generate key pair for homomorphic encryption
    pub fn generate_keys(&mut self) -> Result<()> {
        match self.config.scheme {
            HomomorphicScheme::BFV => self.generate_bfv_keys(),
            HomomorphicScheme::CKKS => self.generate_ckks_keys(),
            HomomorphicScheme::BGV => self.generate_bgv_keys(),
            HomomorphicScheme::TFHE => self.generate_tfhe_keys(),
        }
    }

    /// Generate BFV scheme keys
    fn generate_bfv_keys(&mut self) -> Result<()> {
        // Simplified key generation (use proper HE library in practice)
        self.public_key = Some(vec![0u8; 1024]); // Placeholder
        self.private_key = Some(vec![0u8; 512]); // Placeholder
        self.evaluation_keys = Some(vec![0u8; 2048]); // Placeholder
        Ok(())
    }

    /// Generate CKKS scheme keys
    fn generate_ckks_keys(&mut self) -> Result<()> {
        // Simplified key generation (use proper HE library in practice)
        self.public_key = Some(vec![0u8; 1024]); // Placeholder
        self.private_key = Some(vec![0u8; 512]); // Placeholder
        self.evaluation_keys = Some(vec![0u8; 2048]); // Placeholder
        Ok(())
    }

    /// Generate BGV scheme keys
    fn generate_bgv_keys(&mut self) -> Result<()> {
        // Simplified key generation (use proper HE library in practice)
        self.public_key = Some(vec![0u8; 1024]); // Placeholder
        self.private_key = Some(vec![0u8; 512]); // Placeholder
        self.evaluation_keys = Some(vec![0u8; 2048]); // Placeholder
        Ok(())
    }

    /// Generate TFHE scheme keys
    fn generate_tfhe_keys(&mut self) -> Result<()> {
        // Simplified key generation (use proper HE library in practice)
        self.public_key = Some(vec![0u8; 2048]); // Placeholder
        self.private_key = Some(vec![0u8; 1024]); // Placeholder
        self.evaluation_keys = Some(vec![0u8; 4096]); // Placeholder
        Ok(())
    }

    /// Encrypt data using homomorphic encryption
    pub fn encrypt(&self, plaintext: &[f32]) -> Result<Vec<u8>> {
        if self.public_key.is_none() {
            return Err(TrustformersError::InvalidConfiguration("Keys not generated".to_string()).into());
        }

        // Simplified encryption (use proper HE library in practice)
        let mut ciphertext = Vec::new();
        for &value in plaintext {
            ciphertext.extend_from_slice(&value.to_le_bytes().into());
        }

        // Add some dummy encryption overhead
        ciphertext.extend_from_slice(&[0u8; 64]);

        Ok(ciphertext)
    }

    /// Decrypt data using homomorphic encryption
    pub fn decrypt(&self, ciphertext: &[u8]) -> Result<Vec<f32>> {
        if self.private_key.is_none() {
            return Err(TrustformersError::InvalidConfiguration("Private key not available".to_string()).into());
        }

        // Simplified decryption (use proper HE library in practice)
        let data_len = (ciphertext.len() - 64) / 4; // Remove dummy overhead
        let mut plaintext = Vec::with_capacity(data_len);

        for i in 0..data_len {
            let start = i * 4;
            let end = start + 4;
            if end <= ciphertext.len() - 64 {
                let bytes = &ciphertext[start..end];
                let value = f32::from_le_bytes([bytes[0], bytes[1], bytes[2], bytes[3]]);
                plaintext.push(value);
            }
        }

        Ok(plaintext)
    }

    /// Perform homomorphic addition
    pub fn homomorphic_add(&self, ciphertext1: &[u8], ciphertext2: &[u8]) -> Result<Vec<u8>> {
        // Simplified homomorphic addition (use proper HE library in practice)
        if ciphertext1.len() != ciphertext2.len() {
            return Err(TrustformersError::InvalidConfiguration("Ciphertext sizes mismatch".to_string()).into());
        }

        let mut result = Vec::with_capacity(ciphertext1.len());
        for (a, b) in ciphertext1.iter().zip(ciphertext2.iter()) {
            result.push(a.wrapping_add(*b));
        }

        Ok(result)
    }

    /// Get public key
    pub fn get_public_key(&self) -> Option<&[u8]> {
        self.public_key.as_deref()
    }

    /// Get evaluation keys
    pub fn get_evaluation_keys(&self) -> Option<&[u8]> {
        self.evaluation_keys.as_deref()
    }
}

/// Secure multi-party computation manager
#[derive(Debug)]
pub struct SecureMPCManager {
    config: SecureMPCConfig,
    party_id: u32,
    secret_shares: Vec<Vec<u8>>,
}

impl SecureMPCManager {
    /// Create a new secure MPC manager
    pub fn new(config: SecureMPCConfig, party_id: u32) -> Result<Self> {
        Ok(Self {
            config,
            party_id,
            secret_shares: Vec::new(),
        })
    }

    /// Generate secret shares for a value
    pub fn generate_secret_shares(&mut self, secret: &[u8]) -> Result<Vec<Vec<u8>>> {
        match self.config.protocol {
            MPCProtocol::ShamirSecretSharing => self.shamir_secret_sharing(secret),
            MPCProtocol::BGW => self.bgw_protocol(secret),
            MPCProtocol::GMW => self.gmw_protocol(secret),
            MPCProtocol::SPDZ => self.spdz_protocol(secret),
            MPCProtocol::ABY => self.aby_protocol(secret),
            MPCProtocol::CrypTFlow => self.cryptflow_protocol(secret),
        }
    }

    /// Shamir's secret sharing implementation (simplified)
    fn shamir_secret_sharing(&mut self, secret: &[u8]) -> Result<Vec<Vec<u8>>> {
        let mut shares = Vec::new();

        // Simplified secret sharing (use proper cryptographic library in practice)
        for i in 1..=self.config.num_parties {
            let mut share = secret.to_vec();
            // Add some simple polynomial evaluation (simplified)
            for byte in &mut share {
                *byte = byte.wrapping_add(i as u8);
            }
            shares.push(share);
        }

        self.secret_shares = shares.clone();
        Ok(shares)
    }

    /// BGW protocol implementation (simplified)
    fn bgw_protocol(&mut self, secret: &[u8]) -> Result<Vec<Vec<u8>>> {
        // Simplified BGW implementation
        self.shamir_secret_sharing(secret)
    }

    /// GMW protocol implementation (simplified)
    fn gmw_protocol(&mut self, secret: &[u8]) -> Result<Vec<Vec<u8>>> {
        // Simplified GMW implementation
        self.shamir_secret_sharing(secret)
    }

    /// SPDZ protocol implementation (simplified)
    fn spdz_protocol(&mut self, secret: &[u8]) -> Result<Vec<Vec<u8>>> {
        // Simplified SPDZ implementation
        self.shamir_secret_sharing(secret)
    }

    /// ABY protocol implementation (simplified)
    fn aby_protocol(&mut self, secret: &[u8]) -> Result<Vec<Vec<u8>>> {
        // Simplified ABY implementation
        self.shamir_secret_sharing(secret)
    }

    /// CrypTFlow protocol implementation (simplified)
    fn cryptflow_protocol(&mut self, secret: &[u8]) -> Result<Vec<Vec<u8>>> {
        // Simplified CrypTFlow implementation
        self.shamir_secret_sharing(secret)
    }

    /// Reconstruct secret from shares
    pub fn reconstruct_secret(&self, shares: &[Vec<u8>]) -> Result<Vec<u8>> {
        if shares.len() < self.config.threshold as usize {
            return Err(TrustformersError::InvalidConfiguration("Insufficient shares for reconstruction".to_string()).into());
        }

        // Simplified reconstruction (use proper cryptographic library in practice)
        let secret_length = shares[0].len();
        let mut reconstructed = vec![0u8; secret_length];

        for i in 0..secret_length {
            let mut sum = 0u8;
            for j in 0..self.config.threshold as usize {
                sum = sum.wrapping_add(shares[j][i]);
            }
            // Simplified Lagrange interpolation (just remove the added values)
            reconstructed[i] = sum.wrapping_sub(((1 + self.config.threshold) * self.config.threshold / 2) as u8);
        }

        Ok(reconstructed)
    }

    /// Perform secure computation on secret shares
    pub fn secure_add(&self, shares1: &[Vec<u8>], shares2: &[Vec<u8>]) -> Result<Vec<Vec<u8>>> {
        if shares1.len() != shares2.len() {
            return Err(TrustformersError::InvalidConfiguration("Share counts mismatch".to_string()).into());
        }

        let mut result_shares = Vec::new();
        for (share1, share2) in shares1.iter().zip(shares2.iter()) {
            if share1.len() != share2.len() {
                return Err(TrustformersError::InvalidConfiguration("Share sizes mismatch".to_string()).into());
            }

            let mut result_share = Vec::with_capacity(share1.len().into());
            for (a, b) in share1.iter().zip(share2.iter()) {
                result_share.push(a.wrapping_add(*b));
            }
            result_shares.push(result_share);
        }

        Ok(result_shares)
    }
}

/// Zero-knowledge proof manager
#[derive(Debug)]
pub struct ZKProofManager {
    config: ZKProofConfig,
    proving_key: Option<Vec<u8>>,
    verification_key: Option<Vec<u8>>,
}

impl ZKProofManager {
    /// Create a new zero-knowledge proof manager
    pub fn new(config: ZKProofConfig) -> Result<Self> {
        Ok(Self {
            config,
            proving_key: None,
            verification_key: None,
        })
    }

    /// Setup zero-knowledge proof system
    pub fn setup(&mut self) -> Result<()> {
        match self.config.proof_system {
            ZKProofSystem::ZkSNARKs => self.setup_zk_snarks(),
            ZKProofSystem::ZkSTARKs => self.setup_zk_starks(),
            ZKProofSystem::Bulletproofs => self.setup_bulletproofs(),
            ZKProofSystem::PLONK => self.setup_plonk(),
        }
    }

    /// Setup zk-SNARKs
    fn setup_zk_snarks(&mut self) -> Result<()> {
        // Simplified setup (use proper ZK library in practice)
        self.proving_key = Some(vec![0u8; 1024]);
        self.verification_key = Some(vec![0u8; 256]);
        Ok(())
    }

    /// Setup zk-STARKs
    fn setup_zk_starks(&mut self) -> Result<()> {
        // Simplified setup (use proper ZK library in practice)
        self.proving_key = Some(vec![0u8; 512]);
        self.verification_key = Some(vec![0u8; 128]);
        Ok(())
    }

    /// Setup Bulletproofs
    fn setup_bulletproofs(&mut self) -> Result<()> {
        // Simplified setup (use proper ZK library in practice)
        self.proving_key = Some(vec![0u8; 2048]);
        self.verification_key = Some(vec![0u8; 512]);
        Ok(())
    }

    /// Setup PLONK
    fn setup_plonk(&mut self) -> Result<()> {
        // Simplified setup (use proper ZK library in practice)
        self.proving_key = Some(vec![0u8; 1536]);
        self.verification_key = Some(vec![0u8; 384]);
        Ok(())
    }

    /// Generate a zero-knowledge proof
    pub fn generate_proof(&self, statement: &[u8], witness: &[u8]) -> Result<Vec<u8>> {
        if self.proving_key.is_none() {
            return Err(TrustformersError::InvalidConfiguration("Proving key not generated".to_string()).into());
        }

        // Simplified proof generation (use proper ZK library in practice)
        let mut proof = Vec::new();
        proof.extend_from_slice(statement);
        proof.extend_from_slice(witness);
        proof.extend_from_slice(&[0u8; 256]); // Dummy proof data

        Ok(proof)
    }

    /// Verify a zero-knowledge proof
    pub fn verify_proof(&self, proof: &[u8], statement: &[u8]) -> Result<bool> {
        if self.verification_key.is_none() {
            return Err(TrustformersError::InvalidConfiguration("Verification key not generated".to_string()).into());
        }

        // Simplified verification (use proper ZK library in practice)
        if proof.len() < statement.len() + 256 {
            return Ok(false);
        }

        let embedded_statement = &proof[..statement.len()];
        Ok(embedded_statement == statement)
    }

    /// Get verification key
    pub fn get_verification_key(&self) -> Option<&[u8]> {
        self.verification_key.as_deref()
    }
}

/// Digital signature manager
#[derive(Debug)]
pub struct DigitalSignatureManager {
    scheme: DigitalSignatureScheme,
    private_key: Option<Vec<u8>>,
    public_key: Option<Vec<u8>>,
}

impl DigitalSignatureManager {
    /// Create a new digital signature manager
    pub fn new(scheme: DigitalSignatureScheme) -> Result<Self> {
        Ok(Self {
            scheme,
            private_key: None,
            public_key: None,
        })
    }

    /// Generate key pair
    pub fn generate_keys(&mut self) -> Result<()> {
        match self.scheme {
            DigitalSignatureScheme::ECDSA => self.generate_ecdsa_keys(),
            DigitalSignatureScheme::EdDSA => self.generate_eddsa_keys(),
            DigitalSignatureScheme::RSAPSS => self.generate_rsa_keys(),
            DigitalSignatureScheme::BLS => self.generate_bls_keys(),
            DigitalSignatureScheme::RingSignature => self.generate_ring_signature_keys(),
        }
    }

    /// Generate ECDSA keys
    fn generate_ecdsa_keys(&mut self) -> Result<()> {
        self.private_key = Some(vec![0u8; 32]);
        self.public_key = Some(vec![0u8; 64]);
        Ok(())
    }

    /// Generate EdDSA keys
    fn generate_eddsa_keys(&mut self) -> Result<()> {
        self.private_key = Some(vec![0u8; 32]);
        self.public_key = Some(vec![0u8; 32]);
        Ok(())
    }

    /// Generate RSA keys
    fn generate_rsa_keys(&mut self) -> Result<()> {
        self.private_key = Some(vec![0u8; 256]);
        self.public_key = Some(vec![0u8; 256]);
        Ok(())
    }

    /// Generate BLS keys
    fn generate_bls_keys(&mut self) -> Result<()> {
        self.private_key = Some(vec![0u8; 32]);
        self.public_key = Some(vec![0u8; 48]);
        Ok(())
    }

    /// Generate ring signature keys
    fn generate_ring_signature_keys(&mut self) -> Result<()> {
        self.private_key = Some(vec![0u8; 32]);
        self.public_key = Some(vec![0u8; 64]);
        Ok(())
    }

    /// Sign a message
    pub fn sign(&self, message: &[u8]) -> Result<Vec<u8>> {
        if self.private_key.is_none() {
            return Err(TrustformersError::InvalidConfiguration("Private key not generated".to_string()).into());
        }

        // Simplified signing (use proper cryptographic library in practice)
        let mut signature = Vec::new();
        signature.extend_from_slice(message);
        signature.extend_from_slice(&[0u8; 64]); // Dummy signature

        Ok(signature)
    }

    /// Verify a signature
    pub fn verify(&self, message: &[u8], signature: &[u8]) -> Result<bool> {
        if self.public_key.is_none() {
            return Err(TrustformersError::InvalidConfiguration("Public key not generated".to_string()).into());
        }

        // Simplified verification (use proper cryptographic library in practice)
        if signature.len() < message.len() + 64 {
            return Ok(false);
        }

        let embedded_message = &signature[..message.len()];
        Ok(embedded_message == message)
    }

    /// Get public key
    pub fn get_public_key(&self) -> Option<&[u8]> {
        self.public_key.as_deref()
    }
}

impl Default for CryptographicConfig {
    fn default() -> Self {
        Self {
            aggregation_protocol: SecureAggregationProtocol::default(),
            homomorphic_encryption: HomomorphicEncryptionConfig::default(),
            secure_mpc: SecureMPCConfig::default(),
            signature_scheme: DigitalSignatureScheme::default(),
            key_exchange: KeyExchangeProtocol::default(),
            zero_knowledge_proofs: ZKProofConfig::default(),
        }
    }
}

impl Default for HomomorphicEncryptionConfig {
    fn default() -> Self {
        Self {
            scheme: HomomorphicScheme::default(),
            security_level: 128,
            poly_modulus_degree: 8192,
            coeff_modulus: vec![60, 40, 40, 60],
            plaintext_modulus: 1024,
            optimization_level: OptimizationLevel::Advanced,
        }
    }
}

impl Default for SecureMPCConfig {
    fn default() -> Self {
        Self {
            protocol: MPCProtocol::default(),
            num_parties: 3,
            threshold: 2,
            security_parameter: 128,
            communication_rounds: 5,
        }
    }
}

impl Default for ZKProofConfig {
    fn default() -> Self {
        Self {
            proof_system: ZKProofSystem::default(),
            circuit_complexity: 1000,
            proof_size_optimization: true,
            verification_key_caching: true,
        }
    }
}