use nettle_sys::{
aes128_ctx, nettle_aes128_decrypt, nettle_aes128_encrypt,
nettle_aes128_invert_key, nettle_aes128_set_decrypt_key,
nettle_aes128_set_encrypt_key,
};
use std::cmp::min;
use std::mem::{MaybeUninit, transmute};
use std::os::raw::c_void;
use crate::cipher::RawCipherFunctionPointer;
use crate::{cipher::Cipher, Error, Result};
pub struct Aes128 {
context: Box<aes128_ctx>,
}
impl_zeroing_drop_for!(Aes128);
impl Aes128 {
pub fn with_inverted_key(encrypt: &Self) -> Self {
let context = unsafe {
let mut ctx = Box::new(MaybeUninit::uninit());
nettle_aes128_invert_key(ctx.as_mut_ptr(),
encrypt.context.as_ref() as *const _);
transmute(ctx)
};
Aes128 { context }
}
}
impl Cipher for Aes128 {
const BLOCK_SIZE: usize = ::nettle_sys::AES_BLOCK_SIZE as usize;
const KEY_SIZE: usize = ::nettle_sys::AES128_KEY_SIZE as usize;
fn with_encrypt_key(key: &[u8]) -> Result<Aes128> {
if key.len() != Aes128::KEY_SIZE {
return Err(Error::InvalidArgument { argument_name: "key" });
}
let context = unsafe {
let mut ctx = Box::new(MaybeUninit::uninit());
nettle_aes128_set_encrypt_key(ctx.as_mut_ptr(), key.as_ptr());
transmute(ctx)
};
Ok(Aes128 { context })
}
fn with_decrypt_key(key: &[u8]) -> Result<Aes128> {
if key.len() != Aes128::KEY_SIZE {
return Err(Error::InvalidArgument { argument_name: "key" });
}
let context = unsafe {
let mut ctx = Box::new(MaybeUninit::uninit());
nettle_aes128_set_decrypt_key(ctx.as_mut_ptr(), key.as_ptr());
transmute(ctx)
};
Ok(Aes128 { context })
}
fn encrypt(&mut self, dst: &mut [u8], src: &[u8]) {
unsafe {
nettle_aes128_encrypt(
self.context.as_mut() as *mut _,
min(src.len(), dst.len()),
dst.as_mut_ptr(),
src.as_ptr(),
)
};
}
fn decrypt(&mut self, dst: &mut [u8], src: &[u8]) {
unsafe {
nettle_aes128_decrypt(
self.context.as_mut() as *mut _,
min(src.len(), dst.len()),
dst.as_mut_ptr(),
src.as_ptr(),
)
};
}
fn context(&mut self) -> *mut c_void {
(self.context.as_mut() as *mut aes128_ctx) as *mut c_void
}
fn raw_encrypt_function() -> RawCipherFunctionPointer {
RawCipherFunctionPointer::new(nettle_aes128_encrypt)
}
fn raw_decrypt_function() -> RawCipherFunctionPointer {
RawCipherFunctionPointer::new(nettle_aes128_decrypt)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn set_key() {
let key = &(b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16"[..]);
let _ = Aes128::with_encrypt_key(key).unwrap();
let _ = Aes128::with_decrypt_key(key).unwrap();
}
#[test]
fn round_trip() {
let key = vec![
0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x10, 0x11,
0x12, 0x13, 0x14, 0x15, 0x16,
];
let input = vec![
0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x10, 0x11,
0x12, 0x13, 0x14, 0x15, 0x16,
];
let mut cipher = vec![0; 16];
let mut output = vec![0; 16];
let mut enc = Aes128::with_encrypt_key(&key).unwrap();
let mut dec = Aes128::with_decrypt_key(&key).unwrap();
enc.encrypt(&mut cipher, &input);
dec.decrypt(&mut output, &cipher);
assert_eq!(output, input);
}
#[test]
fn round_trip_invert() {
let key = vec![
0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x10, 0x11,
0x12, 0x13, 0x14, 0x15, 0x16,
];
let input = vec![
0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x10, 0x11,
0x12, 0x13, 0x14, 0x15, 0x16,
];
let mut cipher = vec![0; 16];
let mut output = vec![0; 16];
let mut enc = Aes128::with_encrypt_key(&key).unwrap();
let mut dec = Aes128::with_inverted_key(&enc);
enc.encrypt(&mut cipher, &input);
dec.decrypt(&mut output, &cipher);
assert_eq!(output, input);
}
}