anya-core 1.2.0

//! Key Derivation Function Module
//!
//! This module provides key derivation functions for Bitcoin security.

use std::error::Error;

/// Supported key derivation algorithms
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum KdfAlgorithm {
    /// PBKDF2 with HMAC-SHA256
    Pbkdf2,
    /// Argon2id - memory-hard KDF
    Argon2id,
    /// scrypt - memory-hard KDF
    Scrypt,
    /// HKDF - HMAC-based Key Derivation Function
    Hkdf,
}

/// PBKDF2 parameters
#[derive(Debug, Clone)]
pub struct Pbkdf2Params {
    /// Number of iterations
    pub iterations: u32,
    /// Salt value
    pub salt: Vec<u8>,
    /// Output key length in bytes
    pub key_length: usize,
}

impl Default for Pbkdf2Params {
    fn default() -> Self {
        Self {
            iterations: 10_000,
            salt: vec![0u8; 16], // Should be random in practice
            key_length: 32,
        }
    }
}

/// Argon2 parameters
#[derive(Debug, Clone)]
pub struct Argon2Params {
    /// Memory size in KB
    pub memory_cost: u32,
    /// Number of iterations
    pub iterations: u32,
    /// Parallelism factor
    pub parallelism: u32,
    /// Salt value
    pub salt: Vec<u8>,
    /// Output key length in bytes
    pub key_length: usize,
}

impl Default for Argon2Params {
    fn default() -> Self {
        Self {
            memory_cost: 65536, // 64 MB
            iterations: 3,
            parallelism: 4,
            salt: vec![0u8; 16], // Should be random in practice
            key_length: 32,
        }
    }
}

/// Scrypt parameters
#[derive(Debug, Clone)]
pub struct ScryptParams {
    /// CPU/memory cost parameter
    pub n: u32,
    /// Block size parameter
    pub r: u32,
    /// Parallelization parameter
    pub p: u32,
    /// Salt value
    pub salt: Vec<u8>,
    /// Output key length in bytes
    pub key_length: usize,
}

impl Default for ScryptParams {
    fn default() -> Self {
        Self {
            n: 16384, // 2^14
            r: 8,
            p: 1,
            salt: vec![0u8; 16], // Should be random in practice
            key_length: 32,
        }
    }
}

/// Derive a key from a password or passphrase using PBKDF2
pub fn pbkdf2(_password: &[u8], params: &Pbkdf2Params) -> Vec<u8> {
    // Placeholder implementation
    // In a real implementation, we would use a crypto library with PBKDF2 support
    vec![0u8; params.key_length]
}

/// Derive a key from a password or passphrase using Argon2id
pub fn argon2id(_password: &[u8], params: &Argon2Params) -> Vec<u8> {
    // Placeholder implementation
    // In a real implementation, we would use a crypto library with Argon2 support
    vec![0u8; params.key_length]
}

/// Derive a key from a password or passphrase using scrypt
pub fn scrypt(_password: &[u8], params: &ScryptParams) -> Vec<u8> {
    // Placeholder implementation
    // In a real implementation, we would use a crypto library with scrypt support
    vec![0u8; params.key_length]
}

/// Derive a key using HKDF (HMAC-based Key Derivation Function)
pub fn hkdf(_ikm: &[u8], _salt: &[u8], _info: &[u8], key_length: usize) -> Vec<u8> {
    // Placeholder implementation
    // In a real implementation, we would use a crypto library with HKDF support
    vec![0u8; key_length]
}

/// Derive a key using the specified KDF algorithm
pub fn derive_key(
    password: &[u8],
    algorithm: KdfAlgorithm,
    _params: &[u8],
) -> Result<Vec<u8>, Box<dyn Error>> {
    match algorithm {
        KdfAlgorithm::Pbkdf2 => {
            // Parse params as Pbkdf2Params
            let default_params = Pbkdf2Params::default();
            Ok(pbkdf2(password, &default_params))
        }
        KdfAlgorithm::Argon2id => {
            // Parse params as Argon2Params
            let default_params = Argon2Params::default();
            Ok(argon2id(password, &default_params))
        }
        KdfAlgorithm::Scrypt => {
            // Parse params as ScryptParams
            let default_params = ScryptParams::default();
            Ok(scrypt(password, &default_params))
        }
        KdfAlgorithm::Hkdf => {
            // Parse params as salt and info
            Ok(hkdf(password, &[], &[], 32))
        }
    }
}