core/src/encrypting/encryption.rs

use ntru::rand::RNG_DEFAULT;
use ntru::encparams::{DEFAULT_PARAMS_256_BITS};
use ntru::types::{KeyPair, PrivateKey, PublicKey};
use std::str;
use std::u8;
extern crate ntru;



pub fn u8_to_string(key: &Box<[u8]>) -> String {
    let utf = unsafe {str::from_utf8_unchecked(&key)};
    let string = String::from(utf);
    return String::from(string);
}

pub fn public_key_from_sring (pk: String) -> PublicKey {
    let bytes = pk.into_bytes();
    let imported = PublicKey::import(&bytes);
    return imported
}

pub fn private_key_from_sring (pk: String) -> PrivateKey {
    let bytes = pk.into_bytes();
    let imported = PrivateKey::import(&bytes);
    return imported
}

pub fn generate () -> (String, String, KeyPair) {
    let rand_ctx            = ntru::rand::init(&RNG_DEFAULT).unwrap();
    let kp                  = ntru::generate_key_pair(&DEFAULT_PARAMS_256_BITS, &rand_ctx).unwrap();
    // extracting public and private key from kp
    let pub_key             = KeyPair::get_public(&kp);
    let private_key         = KeyPair::get_private(&kp);
    // getting pub and priv key params for exporting
    let pub_key_params      = KeyPair::get_params(&kp).unwrap();
    let private_key_params  = PrivateKey::get_params(&private_key).unwrap();
    // exporting 
    let pub_key_exported:       Box<[u8]>       = PublicKey::export(&pub_key, &pub_key_params);
    let private_key_exported:   Box<[u8]>       = PrivateKey::export(&private_key, &private_key_params);
    // converting to string
    let pub_key_string                          = u8_to_string(&pub_key_exported);
    let private_key_string                      = u8_to_string(&private_key_exported);
    
    return (pub_key_string, private_key_string, kp )
}

pub fn encrypt_message (msg:String, key: PublicKey ) -> String {

    let _msg = msg.into_bytes();
    let rand_ctx = ntru::rand::init(&RNG_DEFAULT).unwrap();
    let encrypted = ntru::encrypt(&_msg, &key, &DEFAULT_PARAMS_256_BITS,
                              &rand_ctx).unwrap();
    let message = u8_to_string(&encrypted);
    return message
}

pub fn decrypt_message(msg: String, kp: &KeyPair) -> String {
    let encrypted_message = msg.into_bytes();
    let decrypted = ntru::decrypt(&encrypted_message, &kp, &DEFAULT_PARAMS_256_BITS).unwrap();
    let decrypted_string = u8_to_string(&decrypted);
    return decrypted_string
}


pub fn test () {
    let (public, private, key_pair) = generate();


    let initial_pub     = KeyPair::get_public(&key_pair);
    let initial_priv    = KeyPair::get_private(&key_pair);

    let final_pub   =  public_key_from_sring(public);
    let final_priv  =  private_key_from_sring(private);

    let bo0 = initial_pub  == &final_pub;
    let bo1 = initial_priv == &final_priv;
    /*
    print!("Pub : {}, Priv : {}", bo0, bo1);

    assert_eq!(initial_pub, &final_pub);
    assert_eq!(initial_priv, &final_priv);
*/
    let encrypted_message = encrypt_message(String::from("hello god"), final_pub);
    let decrypted_message = decrypt_message(encrypted_message, &key_pair);
    print!("Msg was decrypted: {}", decrypted_message);

}