1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156

//! Argon2 memory block functions

use core::{
    convert::{AsMut, AsRef},
    num::Wrapping,
    ops::{BitXor, BitXorAssign},
    slice,
};

#[cfg(feature = "zeroize")]
use zeroize::Zeroize;

const TRUNC: u64 = u32::MAX as u64;

#[rustfmt::skip]
macro_rules! permute_step {
    ($a:expr, $b:expr, $c:expr, $d:expr) => {
        $a = (Wrapping($a) + Wrapping($b) + (Wrapping(2) * Wrapping(($a & TRUNC) * ($b & TRUNC)))).0;
        $d = ($d ^ $a).rotate_right(32);
        $c = (Wrapping($c) + Wrapping($d) + (Wrapping(2) * Wrapping(($c & TRUNC) * ($d & TRUNC)))).0;
        $b = ($b ^ $c).rotate_right(24);

        $a = (Wrapping($a) + Wrapping($b) + (Wrapping(2) * Wrapping(($a & TRUNC) * ($b & TRUNC)))).0;
        $d = ($d ^ $a).rotate_right(16);
        $c = (Wrapping($c) + Wrapping($d) + (Wrapping(2) * Wrapping(($c & TRUNC) * ($d & TRUNC)))).0;
        $b = ($b ^ $c).rotate_right(63);
    };
}

macro_rules! permute {
    (
        $v0:expr, $v1:expr, $v2:expr, $v3:expr,
        $v4:expr, $v5:expr, $v6:expr, $v7:expr,
        $v8:expr, $v9:expr, $v10:expr, $v11:expr,
        $v12:expr, $v13:expr, $v14:expr, $v15:expr,
    ) => {
        permute_step!($v0, $v4, $v8, $v12);
        permute_step!($v1, $v5, $v9, $v13);
        permute_step!($v2, $v6, $v10, $v14);
        permute_step!($v3, $v7, $v11, $v15);
        permute_step!($v0, $v5, $v10, $v15);
        permute_step!($v1, $v6, $v11, $v12);
        permute_step!($v2, $v7, $v8, $v13);
        permute_step!($v3, $v4, $v9, $v14);
    };
}

/// Structure for the (1 KiB) memory block implemented as 128 64-bit words.
#[derive(Copy, Clone, Debug)]
#[repr(align(64))]
pub struct Block([u64; Self::SIZE / 8]);

impl Block {
    /// Memory block size in bytes
    pub const SIZE: usize = 1024;

    /// Returns a Block initialized with zeros.
    pub const fn new() -> Self {
        Self([0u64; Self::SIZE / 8])
    }

    /// Load a block from a block-sized byte slice
    #[inline(always)]
    pub(crate) fn load(&mut self, input: &[u8; Block::SIZE]) {
        for (i, chunk) in input.chunks(8).enumerate() {
            self.0[i] = u64::from_le_bytes(chunk.try_into().expect("should be 8 bytes"));
        }
    }

    /// Iterate over the `u64` values contained in this block
    #[inline(always)]
    pub(crate) fn iter(&self) -> slice::Iter<'_, u64> {
        self.0.iter()
    }

    /// NOTE: do not call this directly. It should only be called via
    /// `Argon2::compress`.
    #[inline(always)]
    pub(crate) fn compress(rhs: &Self, lhs: &Self) -> Self {
        let r = *rhs ^ lhs;

        // Apply permutations rowwise
        let mut q = r;
        for chunk in q.0.chunks_exact_mut(16) {
            #[rustfmt::skip]
            permute!(
                chunk[0], chunk[1], chunk[2], chunk[3],
                chunk[4], chunk[5], chunk[6], chunk[7],
                chunk[8], chunk[9], chunk[10], chunk[11],
                chunk[12], chunk[13], chunk[14], chunk[15],
            );
        }

        // Apply permutations columnwise
        for i in 0..8 {
            let b = i * 2;

            #[rustfmt::skip]
            permute!(
                q.0[b], q.0[b + 1],
                q.0[b + 16], q.0[b + 17],
                q.0[b + 32], q.0[b + 33],
                q.0[b + 48], q.0[b + 49],
                q.0[b + 64], q.0[b + 65],
                q.0[b + 80], q.0[b + 81],
                q.0[b + 96], q.0[b + 97],
                q.0[b + 112], q.0[b + 113],
            );
        }

        q ^= &r;
        q
    }
}

impl Default for Block {
    fn default() -> Self {
        Self([0u64; Self::SIZE / 8])
    }
}

impl AsRef<[u64]> for Block {
    fn as_ref(&self) -> &[u64] {
        &self.0
    }
}

impl AsMut<[u64]> for Block {
    fn as_mut(&mut self) -> &mut [u64] {
        &mut self.0
    }
}

impl BitXor<&Block> for Block {
    type Output = Block;

    fn bitxor(mut self, rhs: &Block) -> Self::Output {
        self ^= rhs;
        self
    }
}

impl BitXorAssign<&Block> for Block {
    fn bitxor_assign(&mut self, rhs: &Block) {
        for (dst, src) in self.0.iter_mut().zip(rhs.0.iter()) {
            *dst ^= src;
        }
    }
}

#[cfg(feature = "zeroize")]
impl Zeroize for Block {
    fn zeroize(&mut self) {
        self.0.zeroize();
    }
}