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use std::fmt::format;
use std::str::FromStr;
//use num_bigint::BigUint;
//use num_traits::Zero;
use crate::crypto_systems::rsa::RSA;
use crate::error::RSAError;
use crate::prelude::*;
use crate::utils::BaseString;
use crate::Traits::Decrypt;
use rug::Integer;
impl Decrypt<RSAError, String, String> for RSA {
/// Decrypts a string using the RSA cipher.
///
/// This requires that the private key is present since we need it for decrypting
///
/// # Arguments
///
/// * `cipher_text` - A `String` that holds the text to be decrypted.
///
/// # Returns
///
/// * A `Result<String, RSAError>` which is `Ok` if the decryption is successful, and `Err` otherwise.
/// The `Ok` variant contains the decrypted text, and the `Err` variant contains an error type.
///
/// # Example
///
/// TODO: make example
fn decrypt(&self, cipher_text: String) -> Result<String, RSAError> {
// since RSA wont always encrypt a string to a new slice of ints that can be decoded we must take in the whole input as a string and interpret it as a number later
let cipher_num = match Integer::from_str(cipher_text.as_str()) {
Ok(num) => num,
Err(e) => return Err(RSAError::Error(e.to_string())),
};
if self.d == 0 {
return Err(RSAError::PrivateKeyNotSet);
}
// decrypt the number
let decrypted_num = cipher_num.secure_pow_mod(&self.d, &self.n);
Ok(decrypted_num.to_string())
}
}
#[cfg(test)]
mod test {
use super::*;
use crate::utils::EncodedString;
use crate::Traits::{Decrypt, Encrypt};
// TODO: make tests for RSA decrypt implementation
#[test]
fn test_decrypt() {
let mut rsa = RSA::from_public(Integer::from(14317u64), Integer::from(7777u64));
match rsa.factorize_and_set_d() {
Ok(_) => {}
Err(e) => println!("{}", e),
};
let cipher_text = "1640".to_string();
let decrypted_text = rsa.decrypt(cipher_text).unwrap();
assert_eq!(decrypted_text, "2612");
}
// broken case 'rsa_sys = ferric_crypto_lib.RSA("4177248169415681", "8650415919381337961")' with cipher_text = '32107833669138743416991214827014308'
// pub key n: '36134934063919959150141797353966441' and e: '1330643366620853071'
#[test]
fn test_decryption() {
let rsa = RSA::new(
Integer::from(4177248169415681u64),
Integer::from(8650415919381337961u64),
);
let cipher_text = "32107833669138743416991214827014308".to_string();
let decrypted_text = rsa.decrypt(cipher_text).unwrap();
let expected =
match EncodedString::from("A19160912120914200502281415181401".to_string()).decode() {
Ok(s) => s,
Err(e) => panic!("{}", e.to_string()),
};
let decrypted = match EncodedString::from("A".to_string() + &decrypted_text).decode() {
Ok(s) => s,
Err(e) => panic!("{}", e.to_string()),
};
assert_eq!(decrypted, expected);
}
}