eva_crypto/

aes.rs

use super::generic::{create_u8x4x4, transpose, u8x4x4, Ops, Permutation};

pub struct AES {
    pub round_keys: Vec<AESstate>,
    pub sbox: [u8; 256],
    pub rsbox: [u8; 256],
}

type AESstate = u8x4x4;

impl AES {
    /// Initialize an AES cipher.
    pub fn new(key: &[u8]) -> AES {
        let rounds = 10 + (key.len() / 4) - 4;
        let mut round_keys = vec![[[0; 4]; 4]; rounds + 1];
        key_expansion(key, &mut round_keys);

        AES {
            round_keys,
            sbox: SBOX,
            rsbox: RSBOX,
        }
    }

    /// Encrypt a block.
    pub fn encrypt(&self, data: &[u8]) -> Vec<u8> {
        let rounds = self.round_keys.len() - 1;
        let mut state = create_u8x4x4(data);
        state = add_round_key(&state, &self.round_keys[0]);

        for i in 1..rounds {
            state = sub_bytes(&state, &self.sbox);
            state = shift_rows(&state);
            state = mix_columns(&state);
            state = add_round_key(&state, &self.round_keys[i]);
        }

        state = sub_bytes(&state, &self.sbox);
        state = shift_rows(&state);
        state = add_round_key(&state, &self.round_keys[rounds]);

        state.concat()
    }

    /// Decrypt a block.
    pub fn decrypt(&self, data: &[u8]) -> Vec<u8> {
        let rounds = self.round_keys.len() - 1;
        let mut state = create_u8x4x4(data);
        state = add_round_key(&state, &self.round_keys[rounds]);

        for i in (1..rounds).rev() {
            state = inv_shift_rows(&state);
            state = inv_sub_bytes(&state, &self.rsbox);
            state = add_round_key(&state, &self.round_keys[i]);
            state = inv_mix_columns(&state);
        }

        state = inv_sub_bytes(&state, &self.rsbox);
        state = inv_shift_rows(&state);
        state = add_round_key(&state, &self.round_keys[0]);

        state.concat()
    }

    // Injection of faults

    pub fn with_sbox(mut self, faulty_sbox: [u8; 256]) -> Self {
        self.sbox = faulty_sbox;
        self
    }

    pub fn with_rsbox(mut self, faulty_rsbox: [u8; 256]) -> Self {
        self.rsbox = faulty_rsbox;
        self
    }

    pub fn with_sbox_byte(mut self, faulty_idx: usize, faulty_val: u8) -> Self {
        let mut sbox = SBOX;
        sbox[faulty_idx] = faulty_val;
        self.sbox = sbox;
        self
    }

    pub fn with_rsbox_byte(mut self, faulty_idx: usize, faulty_val: u8) -> Self {
        let mut rsbox = RSBOX;
        rsbox[faulty_idx] = faulty_val;
        self.sbox = rsbox;
        self
    }
}

fn key_expansion(key: &[u8], round_keys: &mut [AESstate]) {
    let key_words = key.len() / 4;
    debug_assert!(match key_words {
        4 | 6 | 8 => true,
        _ => false,
    });
    let rounds = 10 + key_words - 4;

    for (i, j) in (0..key.len()).step_by(4).enumerate() {
        for n in 0..4 {
            round_keys[i / 4][i % 4][j % 4 + n] = key[j + n];
        }
    }

    for i in key_words..(rounds + 1) * 4 {
        let mut tmp = round_keys[(i - 1) / 4][(i - 1) % 4];
        if i % key_words == 0 {
            tmp = tmp.lrot().sub_sbox(&SBOX);
            tmp[0] ^= RCON[i / key_words - 1];
        } else if key_words > 6 && i % key_words == 4 {
            tmp = tmp.sub_sbox(&SBOX);
        };
        round_keys[i / 4][i % 4] = round_keys[(i - key_words) / 4][(i - key_words) % 4].xor(&tmp);
    }
}

fn add_round_key(state: &AESstate, round_key: &AESstate) -> AESstate {
    state.xor(round_key)
}
fn sub_bytes(state: &AESstate, sbox: &[u8]) -> AESstate {
    state.sub_sbox(sbox)
}
fn inv_sub_bytes(state: &AESstate, rsbox: &[u8]) -> AESstate {
    state.sub_sbox(rsbox)
}
fn shift_rows(state: &AESstate) -> AESstate {
    transpose(&transpose(state).lrot())
}
fn inv_shift_rows(state: &AESstate) -> AESstate {
    transpose(&transpose(state).rrot())
}
fn mix_columns(state: &AESstate) -> AESstate {
    [
        [0x02, 0x01, 0x01, 0x03],
        [0x03, 0x02, 0x01, 0x01],
        [0x01, 0x03, 0x02, 0x01],
        [0x01, 0x01, 0x03, 0x02],
    ]
    .gmul(&state, 8)
}
fn inv_mix_columns(state: &AESstate) -> AESstate {
    [
        [0x0e, 0x09, 0x0d, 0x0b],
        [0x0b, 0x0e, 0x09, 0x0d],
        [0x0d, 0x0b, 0x0e, 0x09],
        [0x09, 0x0d, 0x0b, 0x0e],
    ]
    .gmul(&state, 8)
}

pub static SBOX: [u8; 256] = [
    0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
    0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
    0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
    0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
    0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
    0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
    0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
    0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
    0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
    0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
    0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
    0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
    0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
    0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
    0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
    0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16,
];

pub static RSBOX: [u8; 256] = [
    0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
    0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
    0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
    0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
    0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
    0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
    0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
    0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
    0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
    0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
    0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
    0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
    0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
    0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
    0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
    0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d,
];

pub static RCON: [u8; 10] = [0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36];