origin-crypto-sdk 0.4.0

Standalone cryptographic SDK with classical (Ed25519) and post-quantum (Falcon, SLH-DSA, ML-DSA, NTRU Prime, Curve41417) primitives. Hybrid signing by default.
Documentation 
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

// SPDX-License-Identifier: Apache-2.0

//! R3 polynomial operations (mod 3)

use super::constants::P;

pub mod mod3 {

    pub fn freeze(a: i32) -> i8 {
        let b = a - (3 * ((10923 * a) >> 15));
        let c = b - (3 * ((89_478_485 * b + 134_217_728) >> 28));
        c as i8
    }

    pub fn product(a: i8, b: i8) -> i8 {
        a * b
    }

    pub fn reciprocal(a: i8) -> i8 {
        a
    }

    pub fn quotient(a: i8, b: i8) -> i8 {
        product(a, reciprocal(b))
    }

    pub fn minus_product(a: i8, b: i8, c: i8) -> i8 {
        freeze(a as i32 - b as i32 * c as i32)
    }

    pub fn plus_product(a: i8, b: i8, c: i8) -> i8 {
        freeze(a as i32 + b as i32 * c as i32)
    }

    pub fn sum(a: i8, b: i8) -> i8 {
        freeze(a as i32 + b as i32)
    }

    pub fn mask_set(x: i8) -> isize {
        (-x * x) as isize
    }
}

mod vector {
    use super::mod3;

    pub fn swap(x: &mut [i8], y: &mut [i8], bytes: usize, mask: isize) {
        let c = mask as i8;
        for i in 0..bytes {
            let t = c & (x[i] ^ y[i]);
            x[i] ^= t;
            y[i] ^= t;
        }
    }

    pub fn product(z: &mut [i8], n: usize, x: &[i8], c: i8) {
        for i in 0..n {
            z[i] = mod3::product(x[i], c);
        }
    }

    pub fn minus_product(z: &mut [i8], n: usize, y: &[i8], c: i8) {
        for i in 0..n {
            let x = z[i];
            z[i] = mod3::minus_product(x, y[i], c);
        }
    }

    pub fn shift(z: &mut [i8], n: usize) {
        for i in (1..n).rev() {
            z[i] = z[i - 1];
        }
        z[0] = 0;
    }
}

fn swap_int(x: isize, y: isize, mask: isize) -> (isize, isize) {
    let t = mask & (x ^ y);
    (x ^ t, y ^ t)
}

fn smaller_mask(x: isize, y: isize) -> isize {
    (x - y) >> 31
}

/// Compute reciprocal in R3
pub fn reciprocal(s: [i8; P]) -> (isize, [i8; P]) {
    const LOOPS: usize = 2 * P + 1;
    let mut r = [0i8; P];
    let mut f = [0i8; P + 1];
    f[0] = -1;
    f[1] = -1;
    f[P] = 1;

    let mut g = [0i8; P + 1];
    g[..P].clone_from_slice(&s[..P]);
    let mut d = P as isize;
    let mut e = P as isize;
    let mut u = [0i8; LOOPS + 1];
    let mut v = [0i8; LOOPS + 1];
    v[0] = 1;

    for _ in 0..LOOPS {
        let c = mod3::quotient(g[P], f[P]);
        vector::minus_product(&mut g, P + 1, &f, c);
        vector::shift(&mut g, P + 1);
        vector::minus_product(&mut v, LOOPS + 1, &u, c);
        vector::shift(&mut v, LOOPS + 1);
        e -= 1;
        let m = smaller_mask(e, d) & mod3::mask_set(g[P]);
        let (e_tmp, d_tmp) = swap_int(e, d, m);
        e = e_tmp;
        d = d_tmp;
        vector::swap(&mut f, &mut g, P + 1, m);
        vector::swap(&mut u, &mut v, LOOPS + 1, m);
    }

    vector::product(&mut r, P, &u[P..], mod3::reciprocal(f[P]));
    (smaller_mask(0, d), r)
}

/// Polynomial multiplication in R3
pub fn mult(h: &mut [i8; P], f: [i8; P], g: [i8; P]) {
    let mut fg = [0i8; P * 2 - 1];
    for i in 0..P {
        let mut r = 0i8;
        for j in 0..=i {
            r = mod3::plus_product(r, f[j], g[i - j]);
        }
        fg[i] = r;
    }
    for i in P..(P * 2 - 1) {
        let mut r = 0i8;
        for j in (i - P + 1)..P {
            r = mod3::plus_product(r, f[j], g[i - j]);
        }
        fg[i] = r;
    }
    for i in (P..(P * 2) - 1).rev() {
        let tmp1 = mod3::sum(fg[i - P], fg[i]);
        fg[i - P] = tmp1;
        let tmp2 = mod3::sum(fg[i - P + 1], fg[i]);
        fg[i - P + 1] = tmp2;
    }

    h[..P].clone_from_slice(&fg[..P]);
}