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use crate::constants::*;
use crate::types::Cipher;
use crate::types::CryptResult;
macro_rules! require {
($condition: expr, $err: expr) => {
if !$condition {
return Err($err.into());
}
};
}
#[derive(Debug)]
pub struct Rijndael {
pub block_size: usize,
pub key: Vec<u8>,
pub k_e: Vec<Vec<u32>>,
pub k_d: Vec<Vec<u32>>,
}
impl Rijndael {
#[inline(always)]
pub fn new(key: Vec<u8>, block_size: usize) -> Result<Self, String> {
require!(VALID.contains(&block_size), "Invalid block size");
require!(VALID.contains(&key.len()), "Invalid key size");
let rounds = if block_size == 32 || key.len() == 32 {
14
} else {
if block_size == 16 && key.len() == 16 {
10
} else {
12
}
};
let b_c = block_size / 4;
let mut k_e = vec![vec![0; b_c]; rounds + 1];
let mut k_d = k_e.clone();
let round_key_count = (rounds + 1) * b_c;
let k_c = key.len() / 4;
let mut tk = (0..k_c)
.map(|i| {
let s = 4 * i;
((key[s] as u32) << 24)
| ((key[s + 1] as u32) << 16)
| ((key[s + 2] as u32) << 8)
| (key[s + 3] as u32)
})
.collect::<Vec<u32>>();
let mut t = 0;
let mut j = 0;
while j < k_c && t < round_key_count {
k_e[t / b_c][t % b_c] = tk[j];
k_d[rounds - (t / b_c)][t % b_c] = tk[j];
j += 1;
t += 1;
}
let mut r_con_pointer = 0;
loop {
let mut tt = tk[k_c - 1];
tk[0] ^= ((S[(tt >> 16) as usize & 0xFF] & 0xFF) as u32) << 24
^ ((S[(tt >> 8) as usize & 0xFF] & 0xFF) as u32) << 16
^ ((S[tt as usize & 0xFF] & 0xFF) as u32) << 8
^ ((S[(tt >> 24) as usize & 0xFF] & 0xFF) as u32)
^ ((R_CON[r_con_pointer] & 0xFF) as u32) << 24;
r_con_pointer += 1;
if k_c != 8 {
for i in 1..k_c {
tk[i] ^= tk[i - 1];
}
} else {
for i in 1..(k_c / 2) {
tk[i] ^= tk[i - 1];
}
tt = tk[((k_c / 2) - 1)];
tk[(k_c / 2)] ^= ((S[tt as usize & 0xFF] & 0xFF) as u32)
^ ((S[(tt >> 8) as usize & 0xFF] & 0xFF) as u32) << 8
^ ((S[(tt >> 16) as usize & 0xFF] & 0xFF) as u32) << 16
^ ((S[(tt >> 24) as usize & 0xFF] & 0xFF) as u32) << 24;
for i in ((k_c / 2) + 1)..k_c {
tk[i] ^= tk[(i - 1)];
}
}
j = 0;
while j < k_c && t < round_key_count {
k_e[(t / b_c)][(t % b_c)] = tk[j];
k_d[(rounds - (t / b_c))][(t % b_c)] = tk[j];
j += 1;
t += 1;
}
if t >= round_key_count {
break;
}
}
for r in 1..rounds {
for j in 0..b_c {
let tt = k_d[r][j];
k_d[r][j] = U1[(tt >> 24) as usize & 0xFF]
^ U2[(tt >> 16) as usize & 0xFF]
^ U3[(tt >> 8) as usize & 0xFF]
^ U4[tt as usize & 0xFF];
}
}
Ok(Self {
block_size,
key,
k_e,
k_d,
})
}
pub fn encrypt(&self, source: &Vec<u8>) -> Result<Cipher, &'static str> {
require!(source.len() == self.block_size, "wrong block length");
let b_c = self.block_size / 4;
let rounds = self.k_e.len() - 1;
let s_c = match b_c {
4 => 0,
6 => 1,
_ => 2,
};
let s1 = SHIFTS[s_c][1][0];
let s2 = SHIFTS[s_c][2][0];
let s3 = SHIFTS[s_c][3][0];
let mut a = vec![0; b_c];
let mut t = Vec::with_capacity(b_c);
for i in 0..b_c {
let s = 4 * i;
t.push(
((source[s] as u32) << 24
| (source[s + 1] as u32) << 16
| (source[s + 2] as u32) << 8
| (source[s + 3] as u32))
^ self.k_e[0][i],
);
}
for r in 1..rounds {
for i in 0..b_c {
a[i] = (T1[(t[i] >> 24) as usize & 0xFF]
^ T2[(t[(i + s1 as usize) % b_c] >> 16) as usize & 0xFF]
^ T3[(t[(i + s2 as usize) % b_c] >> 8) as usize & 0xFF]
^ T4[t[(i + s3 as usize) % b_c] as usize & 0xFF])
^ self.k_e[r][i];
}
t = a.clone();
}
let mut result = Vec::with_capacity(source.len());
for i in 0..b_c {
let tt = self.k_e[rounds][i];
result.push(((S[((t[i] >> 24) as usize & 0xFF)] as u32 ^ (tt >> 24)) & 0xFF) as u8);
result.push(
((S[((t[((i + s1 as usize) % b_c)] >> 16) as usize & 0xFF)] as u32 ^ (tt >> 16))
& 0xFF) as u8,
);
result.push(
((S[((t[((i + s2 as usize) % b_c)] >> 8) as usize & 0xFF)] as u32 ^ (tt >> 8))
& 0xFF) as u8,
);
result.push(
((S[(t[((i + s3 as usize) % b_c)] as usize & 0xFF)] as u32 ^ tt) & 0xFF) as u8,
);
}
Ok(result)
}
#[inline(always)]
pub fn decrypt(&self, block_cipher: &Cipher) -> Result<CryptResult, String> {
require!(block_cipher.len() == self.block_size, "wrong block length");
let b_c = self.block_size / 4;
let rounds = self.k_d.len() - 1;
let s_c = match b_c {
4 => 0,
6 => 1,
_ => 2,
};
let s1 = SHIFTS[s_c][1][1];
let s2 = SHIFTS[s_c][2][1];
let s3 = SHIFTS[s_c][3][1];
let mut a = vec![0; b_c];
let mut t = a.clone();
for i in 0..b_c {
let s = 4 * i;
t[i] = ((block_cipher[s] as u32) << 24
| (block_cipher[s + 1] as u32) << 16
| (block_cipher[s + 2] as u32) << 8
| (block_cipher[s + 3] as u32))
^ self.k_d[0][i];
}
for r in 1..rounds {
for i in 0..b_c {
a[i] = (T5[(t[i] >> 24) as usize & 0xFF]
^ T6[(t[(i + s1 as usize) % b_c] >> 16) as usize & 0xFF]
^ T7[(t[(i + s2 as usize) % b_c] >> 8) as usize & 0xFF]
^ T8[t[(i + s3 as usize) % b_c] as usize & 0xFF])
^ self.k_d[r][i];
}
t = a.clone();
}
let mut result = Vec::with_capacity(block_cipher.len());
for i in 0..b_c {
let tt = self.k_d[rounds][i];
result.push(((SI[((t[i] >> 24) as usize & 0xFF)] as u32 ^ (tt >> 24)) & 0xFF) as u8);
result.push(
((SI[((t[((i + s1 as usize) % b_c)] >> 16) as usize & 0xFF)] as u32 ^ (tt >> 16))
& 0xFF) as u8,
);
result.push(
((SI[((t[((i + s2 as usize) % b_c)] >> 8) as usize & 0xFF)] as u32 ^ (tt >> 8))
& 0xFF) as u8,
);
result.push(
((SI[(t[((i + s3 as usize) % b_c)] as usize & 0xFF)] as u32 ^ tt) & 0xFF) as u8,
);
}
Ok(result)
}
}
