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aes: soft hazmat backend
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The `hazmat` API provides access to the raw AES cipher round, equivalent
inverse cipher round, mix columns, and inverse mix column operations.

This commit wires up support in the "soft" backend (or more
specifically, both the 32-bit and 64-bit fixsliced backends).

It would benefit from a parallel API instead of what's currently
provided, however that's left for future work.
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@tarcieri
tarcieri committed May 31, 2021
1 parent 92704fc commit 4cbc4f0
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Showing 4 changed files with 127 additions and 33 deletions.
2 changes: 1 addition & 1 deletion aes/Cargo.lock
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77 changes: 62 additions & 15 deletions aes/src/soft/fixslice32.rs
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Expand Up @@ -295,7 +295,7 @@ pub(crate) fn aes128_decrypt(rkeys: &FixsliceKeys128, blocks: &mut [Block]) {

add_round_key(&mut state, &rkeys[..8]);

inv_bitslice(&mut state, blocks);
inv_bitslice(&state, blocks);
}

/// Fully-fixsliced AES-128 encryption (the ShiftRows is completely omitted).
Expand Down Expand Up @@ -352,7 +352,7 @@ pub(crate) fn aes128_encrypt(rkeys: &FixsliceKeys128, blocks: &mut [Block]) {
sub_bytes(&mut state);
add_round_key(&mut state, &rkeys[80..]);

inv_bitslice(&mut state, blocks);
inv_bitslice(&state, blocks);
}

/// Fully-fixsliced AES-192 decryption (the InvShiftRows is completely omitted).
Expand Down Expand Up @@ -403,7 +403,7 @@ pub(crate) fn aes192_decrypt(rkeys: &FixsliceKeys192, blocks: &mut [Block]) {

add_round_key(&mut state, &rkeys[..8]);

inv_bitslice(&mut state, blocks);
inv_bitslice(&state, blocks);
}

/// Fully-fixsliced AES-192 encryption (the ShiftRows is completely omitted).
Expand Down Expand Up @@ -454,7 +454,7 @@ pub(crate) fn aes192_encrypt(rkeys: &FixsliceKeys192, blocks: &mut [Block]) {
sub_bytes(&mut state);
add_round_key(&mut state, &rkeys[96..]);

inv_bitslice(&mut state, blocks);
inv_bitslice(&state, blocks);
}

/// Fully-fixsliced AES-256 decryption (the InvShiftRows is completely omitted).
Expand Down Expand Up @@ -511,7 +511,7 @@ pub(crate) fn aes256_decrypt(rkeys: &FixsliceKeys256, blocks: &mut [Block]) {

add_round_key(&mut state, &rkeys[..8]);

inv_bitslice(&mut state, blocks);
inv_bitslice(&state, blocks);
}

/// Fully-fixsliced AES-256 encryption (the ShiftRows is completely omitted).
Expand Down Expand Up @@ -568,7 +568,7 @@ pub(crate) fn aes256_encrypt(rkeys: &FixsliceKeys256, blocks: &mut [Block]) {
sub_bytes(&mut state);
add_round_key(&mut state, &rkeys[112..]);

inv_bitslice(&mut state, blocks);
inv_bitslice(&state, blocks);
}

/// Note that the 4 bitwise NOT (^= 0xffffffff) are accounted for here so that it is a true
Expand Down Expand Up @@ -1234,7 +1234,7 @@ fn bitslice(output: &mut [u32], input0: &[u8], input1: &[u8]) {
}

/// Un-bitslice a 256-bit internal state into two 128-bit blocks of output.
fn inv_bitslice(input: &mut [u32], output: &mut [Block]) {
fn inv_bitslice(input: &[u32], output: &mut [Block]) {
debug_assert_eq!(input.len(), 8);
debug_assert_eq!(output.len(), 2);

Expand Down Expand Up @@ -1380,29 +1380,76 @@ fn rotate_rows_and_columns_2_2(x: u32) -> u32 {
/// the AES round function gated under the `hazmat` crate feature.
#[cfg(feature = "hazmat")]
pub(crate) mod hazmat {
use super::{
add_round_key, bitslice, inv_bitslice, inv_mix_columns_0, inv_shift_rows_1, inv_sub_bytes,
mix_columns_0, shift_rows_1, sub_bytes, sub_bytes_nots, State,
};
use crate::Block;

/// AES cipher (encrypt) round function.
#[inline]
pub(crate) fn cipher_round(_block: &mut Block, _round_key: &Block) {
todo!();
pub(crate) fn cipher_round(block: &mut Block, round_key: &Block) {
let mut rkeys = [0u32; 8];
let mut state = State::default();

// TODO(tarcieri): parallel operation
bitslice(&mut rkeys, &round_key, &round_key);
bitslice(&mut state, &block, &block);
sub_bytes(&mut state);
sub_bytes_nots(&mut state);
shift_rows_1(&mut state);
mix_columns_0(&mut state);
add_round_key(&mut state, &rkeys);

let mut out = [Block::default(); 2];
inv_bitslice(&state, &mut out);
block.copy_from_slice(&out[0]);
}

/// AES cipher (encrypt) round function.
#[inline]
pub(crate) fn equiv_inv_cipher_round(_block: &mut Block, _round_key: &Block) {
todo!();
pub(crate) fn equiv_inv_cipher_round(block: &mut Block, round_key: &Block) {
let mut rkeys = [0u32; 8];
let mut state = State::default();

// TODO(tarcieri): parallel operation
bitslice(&mut rkeys, &round_key, &round_key);
bitslice(&mut state, &block, &block);

sub_bytes_nots(&mut state);
inv_sub_bytes(&mut state);
inv_shift_rows_1(&mut state);
inv_mix_columns_0(&mut state);
add_round_key(&mut state, &rkeys);

let mut out = [Block::default(); 2];
inv_bitslice(&state, &mut out);
block.copy_from_slice(&out[0]);
}

/// AES mix columns function.
#[inline]
pub(crate) fn mix_columns(_block: &mut Block) {
todo!();
pub(crate) fn mix_columns(block: &mut Block) {
let mut state = State::default();
bitslice(&mut state, &block, &block);

mix_columns_0(&mut state);

let mut out = [Block::default(); 2];
inv_bitslice(&state, &mut out);
block.copy_from_slice(&out[0]);
}

/// AES inverse mix columns function.
#[inline]
pub(crate) fn inv_mix_columns(_block: &mut Block) {
todo!();
pub(crate) fn inv_mix_columns(block: &mut Block) {
let mut state = State::default();
bitslice(&mut state, &block, &block);

inv_mix_columns_0(&mut state);

let mut out = [Block::default(); 2];
inv_bitslice(&state, &mut out);
block.copy_from_slice(&out[0]);
}
}
79 changes: 63 additions & 16 deletions aes/src/soft/fixslice64.rs
View file
Expand Up @@ -317,7 +317,7 @@ pub(crate) fn aes128_decrypt(rkeys: &FixsliceKeys128, blocks: &mut [Block]) {

add_round_key(&mut state, &rkeys[..8]);

inv_bitslice(&mut state, blocks);
inv_bitslice(&state, blocks);
}

/// Fully-fixsliced AES-128 encryption (the ShiftRows is completely omitted).
Expand Down Expand Up @@ -374,7 +374,7 @@ pub(crate) fn aes128_encrypt(rkeys: &FixsliceKeys128, blocks: &mut [Block]) {
sub_bytes(&mut state);
add_round_key(&mut state, &rkeys[80..]);

inv_bitslice(&mut state, blocks);
inv_bitslice(&state, blocks);
}

/// Fully-fixsliced AES-192 decryption (the InvShiftRows is completely omitted).
Expand Down Expand Up @@ -425,7 +425,7 @@ pub(crate) fn aes192_decrypt(rkeys: &FixsliceKeys192, blocks: &mut [Block]) {

add_round_key(&mut state, &rkeys[..8]);

inv_bitslice(&mut state, blocks);
inv_bitslice(&state, blocks);
}

/// Fully-fixsliced AES-192 encryption (the ShiftRows is completely omitted).
Expand Down Expand Up @@ -476,7 +476,7 @@ pub(crate) fn aes192_encrypt(rkeys: &FixsliceKeys192, blocks: &mut [Block]) {
sub_bytes(&mut state);
add_round_key(&mut state, &rkeys[96..]);

inv_bitslice(&mut state, blocks);
inv_bitslice(&state, blocks);
}

/// Fully-fixsliced AES-256 decryption (the InvShiftRows is completely omitted).
Expand Down Expand Up @@ -533,7 +533,7 @@ pub(crate) fn aes256_decrypt(rkeys: &FixsliceKeys256, blocks: &mut [Block]) {

add_round_key(&mut state, &rkeys[..8]);

inv_bitslice(&mut state, blocks);
inv_bitslice(&state, blocks);
}

/// Fully-fixsliced AES-256 encryption (the ShiftRows is completely omitted).
Expand Down Expand Up @@ -590,7 +590,7 @@ pub(crate) fn aes256_encrypt(rkeys: &FixsliceKeys256, blocks: &mut [Block]) {
sub_bytes(&mut state);
add_round_key(&mut state, &rkeys[112..]);

inv_bitslice(&mut state, blocks);
inv_bitslice(&state, blocks);
}

/// Note that the 4 bitwise NOT (^= 0xffffffffffffffff) are accounted for here so that it is a true
Expand Down Expand Up @@ -1132,7 +1132,7 @@ fn delta_swap_2(a: &mut u64, b: &mut u64, shift: u32, mask: u64) {
}

/// Applies ShiftRows once on an AES state (or key).
#[cfg(not(feature = "compact"))]
#[cfg(any(not(feature = "compact"), feature = "hazmat"))]
#[inline]
fn shift_rows_1(state: &mut [u64]) {
debug_assert_eq!(state.len(), 8);
Expand Down Expand Up @@ -1274,7 +1274,7 @@ fn bitslice(output: &mut [u64], input0: &[u8], input1: &[u8], input2: &[u8], inp
}

/// Un-bitslice a 512-bit internal state into four 128-bit blocks of output.
fn inv_bitslice(input: &mut [u64], output: &mut [Block]) {
fn inv_bitslice(input: &[u64], output: &mut [Block]) {
debug_assert_eq!(input.len(), 8);
debug_assert_eq!(output.len(), 4);

Expand Down Expand Up @@ -1434,29 +1434,76 @@ fn rotate_rows_and_columns_2_2(x: u64) -> u64 {
/// the AES round function gated under the `hazmat` crate feature.
#[cfg(feature = "hazmat")]
pub(crate) mod hazmat {
use super::{
add_round_key, bitslice, inv_bitslice, inv_mix_columns_0, inv_shift_rows_1, inv_sub_bytes,
mix_columns_0, shift_rows_1, sub_bytes, sub_bytes_nots, State,
};
use crate::Block;

/// AES cipher (encrypt) round function.
#[inline]
pub(crate) fn cipher_round(_block: &mut Block, _round_key: &Block) {
todo!();
pub(crate) fn cipher_round(block: &mut Block, round_key: &Block) {
let mut rkeys = [0u64; 8];
let mut state = State::default();

// TODO(tarcieri): parallel operation
bitslice(&mut rkeys, &round_key, &round_key, &round_key, &round_key);
bitslice(&mut state, &block, &block, &block, &block);
sub_bytes(&mut state);
sub_bytes_nots(&mut state);
shift_rows_1(&mut state);
mix_columns_0(&mut state);
add_round_key(&mut state, &rkeys);

let mut out = [Block::default(); 4];
inv_bitslice(&state, &mut out);
block.copy_from_slice(&out[0]);
}

/// AES cipher (encrypt) round function.
#[inline]
pub(crate) fn equiv_inv_cipher_round(_block: &mut Block, _round_key: &Block) {
todo!();
pub(crate) fn equiv_inv_cipher_round(block: &mut Block, round_key: &Block) {
let mut rkeys = [0u64; 8];
let mut state = State::default();

// TODO(tarcieri): parallel operation
bitslice(&mut rkeys, &round_key, &round_key, &round_key, &round_key);
bitslice(&mut state, &block, &block, &block, &block);

sub_bytes_nots(&mut state);
inv_sub_bytes(&mut state);
inv_shift_rows_1(&mut state);
inv_mix_columns_0(&mut state);
add_round_key(&mut state, &rkeys);

let mut out = [Block::default(); 4];
inv_bitslice(&state, &mut out);
block.copy_from_slice(&out[0]);
}

/// AES mix columns function.
#[inline]
pub(crate) fn mix_columns(_block: &mut Block) {
todo!();
pub(crate) fn mix_columns(block: &mut Block) {
let mut state = State::default();
bitslice(&mut state, &block, &block, &block, &block);

mix_columns_0(&mut state);

let mut out = [Block::default(); 4];
inv_bitslice(&state, &mut out);
block.copy_from_slice(&out[0]);
}

/// AES inverse mix columns function.
#[inline]
pub(crate) fn inv_mix_columns(_block: &mut Block) {
todo!();
pub(crate) fn inv_mix_columns(block: &mut Block) {
let mut state = State::default();
bitslice(&mut state, &block, &block, &block, &block);

inv_mix_columns_0(&mut state);

let mut out = [Block::default(); 4];
inv_bitslice(&state, &mut out);
block.copy_from_slice(&out[0]);
}
}
2 changes: 1 addition & 1 deletion aes/tests/hazmat.rs
View file
@@ -1,7 +1,7 @@
//! Tests for low-level "hazmat" AES functions.

// TODO(tarcieri): support for using the hazmat functions with the `soft` backend
#![cfg(all(feature = "hazmat", not(feature = "force-soft")))]
#![cfg(feature = "hazmat")]

use aes::Block;
use hex_literal::hex;
Expand Down

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