libcrux-sha3 0.0.2-alpha.2

Libcrux SHA-3 implementation
Documentation 
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use crate::traits::internal::*;
use libcrux_intrinsics::avx2::*;

#[inline(always)]
fn rotate_left<const LEFT: i32, const RIGHT: i32>(x: Vec256) -> Vec256 {
    debug_assert!(LEFT + RIGHT == 64);
    // XXX: This could be done more efficiently, if the shift values are multiples of 8.
    mm256_xor_si256(mm256_slli_epi64::<LEFT>(x), mm256_srli_epi64::<RIGHT>(x))
}

#[inline(always)]
fn _veor5q_u64(a: Vec256, b: Vec256, c: Vec256, d: Vec256, e: Vec256) -> Vec256 {
    let ab = mm256_xor_si256(a, b);
    let cd = mm256_xor_si256(c, d);
    let abcd = mm256_xor_si256(ab, cd);
    mm256_xor_si256(abcd, e)
}

#[inline(always)]
fn _vrax1q_u64(a: Vec256, b: Vec256) -> Vec256 {
    mm256_xor_si256(a, rotate_left::<1, 63>(b))
}

#[inline(always)]
fn _vxarq_u64<const LEFT: i32, const RIGHT: i32>(a: Vec256, b: Vec256) -> Vec256 {
    let ab = mm256_xor_si256(a, b);
    rotate_left::<LEFT, RIGHT>(ab)
}

#[inline(always)]
fn _vbcaxq_u64(a: Vec256, b: Vec256, c: Vec256) -> Vec256 {
    mm256_xor_si256(a, mm256_andnot_si256(c, b))
}

#[inline(always)]
fn _veorq_n_u64(a: Vec256, c: u64) -> Vec256 {
    // Casting here is required, doesn't change the value.
    let c = mm256_set1_epi64x(c as i64);
    mm256_xor_si256(a, c)
}

#[inline(always)]
pub(crate) fn load_block<const RATE: usize>(s: &mut [[Vec256; 5]; 5], blocks: [&[u8]; 4]) {
    debug_assert!(RATE <= blocks[0].len() && RATE % 8 == 0 && (RATE % 32 == 8 || RATE % 32 == 16));
    for i in 0..RATE / 32 {
        let v0 = mm256_loadu_si256_u8(&blocks[0][32 * i..32 * (i + 1)]);
        let v1 = mm256_loadu_si256_u8(&blocks[1][32 * i..32 * (i + 1)]);
        let v2 = mm256_loadu_si256_u8(&blocks[2][32 * i..32 * (i + 1)]);
        let v3 = mm256_loadu_si256_u8(&blocks[3][32 * i..32 * (i + 1)]);

        let v0l = mm256_unpacklo_epi64(v0, v1); // 0 0 2 2
        let v1h = mm256_unpackhi_epi64(v0, v1); // 1 1 3 3
        let v2l = mm256_unpacklo_epi64(v2, v3); // 0 0 2 2
        let v3h = mm256_unpackhi_epi64(v2, v3); // 1 1 3 3

        let v0 = mm256_permute2x128_si256::<0x20>(v0l, v2l); // 0 0 0 0
        let v1 = mm256_permute2x128_si256::<0x20>(v1h, v3h); // 1 1 1 1
        let v2 = mm256_permute2x128_si256::<0x31>(v0l, v2l); // 2 2 2 2
        let v3 = mm256_permute2x128_si256::<0x31>(v1h, v3h); // 3 3 3 3

        s[(4 * i) / 5][(4 * i) % 5] = mm256_xor_si256(s[(4 * i) / 5][(4 * i) % 5], v0);
        s[(4 * i + 1) / 5][(4 * i + 1) % 5] =
            mm256_xor_si256(s[(4 * i + 1) / 5][(4 * i + 1) % 5], v1);
        s[(4 * i + 2) / 5][(4 * i + 2) % 5] =
            mm256_xor_si256(s[(4 * i + 2) / 5][(4 * i + 2) % 5], v2);
        s[(4 * i + 3) / 5][(4 * i + 3) % 5] =
            mm256_xor_si256(s[(4 * i + 3) / 5][(4 * i + 3) % 5], v3);
    }

    let rem = RATE % 32; // has to be 8 or 16
    let start = 32 * (RATE / 32);
    let mut u8s = [0u8; 32];
    u8s[0..8].copy_from_slice(&blocks[0][start..start + 8]);
    u8s[8..16].copy_from_slice(&blocks[1][start..start + 8]);
    u8s[16..24].copy_from_slice(&blocks[2][start..start + 8]);
    u8s[24..32].copy_from_slice(&blocks[3][start..start + 8]);
    let u = mm256_loadu_si256_u8(u8s.as_slice());
    let i = (4 * (RATE / 32)) / 5;
    let j = (4 * (RATE / 32)) % 5;
    s[i][j] = mm256_xor_si256(s[i][j], u);
    if rem == 16 {
        let mut u8s = [0u8; 32];
        u8s[0..8].copy_from_slice(&blocks[0][start + 8..start + 16]);
        u8s[8..16].copy_from_slice(&blocks[1][start + 8..start + 16]);
        u8s[16..24].copy_from_slice(&blocks[2][start + 8..start + 16]);
        u8s[24..32].copy_from_slice(&blocks[3][start + 8..start + 16]);
        let u = mm256_loadu_si256_u8(u8s.as_slice());
        let i = (4 * (RATE / 32) + 1) / 5;
        let j = (4 * (RATE / 32) + 1) % 5;
        s[i][j] = mm256_xor_si256(s[i][j], u);
    }
}

#[inline(always)]
pub(crate) fn load_block_full<const RATE: usize>(s: &mut [[Vec256; 5]; 5], blocks: [[u8; 200]; 4]) {
    load_block::<RATE>(
        s,
        [
            &blocks[0] as &[u8],
            &blocks[1] as &[u8],
            &blocks[2] as &[u8],
            &blocks[3] as &[u8],
        ],
    );
}

#[inline(always)]
pub(crate) fn store_block<const RATE: usize>(s: &[[Vec256; 5]; 5], out: [&mut [u8]; 4]) {
    for i in 0..RATE / 32 {
        let v0l = mm256_permute2x128_si256::<0x20>(
            s[(4 * i) / 5][(4 * i) % 5],
            s[(4 * i + 2) / 5][(4 * i + 2) % 5],
        );
        // 0 0 2 2
        let v1h = mm256_permute2x128_si256::<0x20>(
            s[(4 * i + 1) / 5][(4 * i + 1) % 5],
            s[(4 * i + 3) / 5][(4 * i + 3) % 5],
        ); // 1 1 3 3
        let v2l = mm256_permute2x128_si256::<0x31>(
            s[(4 * i) / 5][(4 * i) % 5],
            s[(4 * i + 2) / 5][(4 * i + 2) % 5],
        ); // 0 0 2 2
        let v3h = mm256_permute2x128_si256::<0x31>(
            s[(4 * i + 1) / 5][(4 * i + 1) % 5],
            s[(4 * i + 3) / 5][(4 * i + 3) % 5],
        ); // 1 1 3 3

        let v0 = mm256_unpacklo_epi64(v0l, v1h); // 0 1 2 3
        let v1 = mm256_unpackhi_epi64(v0l, v1h); // 0 1 2 3
        let v2 = mm256_unpacklo_epi64(v2l, v3h); // 0 1 2 3
        let v3 = mm256_unpackhi_epi64(v2l, v3h); // 0 1 2 3

        mm256_storeu_si256_u8(&mut out[0][32 * i..32 * (i + 1)], v0);
        mm256_storeu_si256_u8(&mut out[1][32 * i..32 * (i + 1)], v1);
        mm256_storeu_si256_u8(&mut out[2][32 * i..32 * (i + 1)], v2);
        mm256_storeu_si256_u8(&mut out[3][32 * i..32 * (i + 1)], v3);
    }

    let rem = RATE % 32; // has to be 8 or 16
    let start = 32 * (RATE / 32);
    let mut u8s = [0u8; 32];
    let i = (4 * (RATE / 32)) / 5;
    let j = (4 * (RATE / 32)) % 5;
    mm256_storeu_si256_u8(&mut u8s, s[i][j]);
    out[0][start..start + 8].copy_from_slice(&u8s[0..8]);
    out[1][start..start + 8].copy_from_slice(&u8s[8..16]);
    out[2][start..start + 8].copy_from_slice(&u8s[16..24]);
    out[3][start..start + 8].copy_from_slice(&u8s[24..32]);
    if rem == 16 {
        let mut u8s = [0u8; 32];
        let i = (4 * (RATE / 32) + 1) / 5;
        let j = (4 * (RATE / 32) + 1) % 5;
        mm256_storeu_si256_u8(&mut u8s, s[i][j]);
        out[0][start + 8..start + 16].copy_from_slice(&u8s[0..8]);
        out[1][start + 8..start + 16].copy_from_slice(&u8s[8..16]);
        out[2][start + 8..start + 16].copy_from_slice(&u8s[16..24]);
        out[3][start + 8..start + 16].copy_from_slice(&u8s[24..32]);
    }
}

#[inline(always)]
pub(crate) fn store_block_full<const RATE: usize>(s: &[[Vec256; 5]; 5]) -> [[u8; 200]; 4] {
    let mut out0 = [0u8; 200];
    let mut out1 = [0u8; 200];
    let mut out2 = [0u8; 200];
    let mut out3 = [0u8; 200];
    store_block::<RATE>(s, [&mut out0, &mut out1, &mut out2, &mut out3]);
    [out0, out1, out2, out3]
}

#[inline(always)]
fn slice_4(a: [&[u8]; 4], start: usize, len: usize) -> [&[u8]; 4] {
    [
        &a[0][start..start + len],
        &a[1][start..start + len],
        &a[2][start..start + len],
        &a[3][start..start + len],
    ]
}

#[inline(always)]
fn split_at_mut_4(out: [&mut [u8]; 4], mid: usize) -> ([&mut [u8]; 4], [&mut [u8]; 4]) {
    let [out0, out1, out2, out3] = out;
    let (out00, out01) = out0.split_at_mut(mid);
    let (out10, out11) = out1.split_at_mut(mid);
    let (out20, out21) = out2.split_at_mut(mid);
    let (out30, out31) = out3.split_at_mut(mid);
    ([out00, out10, out20, out30], [out01, out11, out21, out31])
}

impl KeccakItem<4> for Vec256 {
    #[inline(always)]
    fn zero() -> Self {
        mm256_set1_epi64x(0)
    }
    #[inline(always)]
    fn xor5(a: Self, b: Self, c: Self, d: Self, e: Self) -> Self {
        _veor5q_u64(a, b, c, d, e)
    }
    #[inline(always)]
    fn rotate_left1_and_xor(a: Self, b: Self) -> Self {
        _vrax1q_u64(a, b)
    }
    #[inline(always)]
    fn xor_and_rotate<const LEFT: i32, const RIGHT: i32>(a: Self, b: Self) -> Self {
        _vxarq_u64::<LEFT, RIGHT>(a, b)
    }
    #[inline(always)]
    fn and_not_xor(a: Self, b: Self, c: Self) -> Self {
        _vbcaxq_u64(a, b, c)
    }
    #[inline(always)]
    fn xor_constant(a: Self, c: u64) -> Self {
        _veorq_n_u64(a, c)
    }
    #[inline(always)]
    fn xor(a: Self, b: Self) -> Self {
        mm256_xor_si256(a, b)
    }
    #[inline(always)]
    fn load_block<const BLOCKSIZE: usize>(a: &mut [[Self; 5]; 5], b: [&[u8]; 4]) {
        load_block::<BLOCKSIZE>(a, b)
    }
    #[inline(always)]
    fn store_block<const BLOCKSIZE: usize>(a: &[[Self; 5]; 5], b: [&mut [u8]; 4]) {
        store_block::<BLOCKSIZE>(a, b)
    }
    #[inline(always)]
    fn load_block_full<const BLOCKSIZE: usize>(a: &mut [[Self; 5]; 5], b: [[u8; 200]; 4]) {
        load_block_full::<BLOCKSIZE>(a, b)
    }
    #[inline(always)]
    fn store_block_full<const BLOCKSIZE: usize>(a: &[[Self; 5]; 5]) -> [[u8; 200]; 4] {
        store_block_full::<BLOCKSIZE>(a)
    }
    #[inline(always)]
    fn slice_n(a: [&[u8]; 4], start: usize, len: usize) -> [&[u8]; 4] {
        slice_4(a, start, len)
    }
    #[inline(always)]
    fn split_at_mut_n(a: [&mut [u8]; 4], mid: usize) -> ([&mut [u8]; 4], [&mut [u8]; 4]) {
        split_at_mut_4(a, mid)
    }
}