crypto_bigint/modular/boxed_monty_form/
neg.rs

1//! Negations of boxed integers in Montgomery form.
2
3use super::BoxedMontyForm;
4use core::ops::Neg;
5
6impl BoxedMontyForm {
7    /// Negates the number.
8    pub fn neg(&self) -> Self {
9        Self {
10            montgomery_form: self.montgomery_form.neg_mod(&self.params.modulus),
11            params: self.params.clone(),
12        }
13    }
14}
15
16impl Neg for BoxedMontyForm {
17    type Output = Self;
18    fn neg(self) -> Self {
19        BoxedMontyForm::neg(&self)
20    }
21}
22
23impl Neg for &BoxedMontyForm {
24    type Output = BoxedMontyForm;
25    fn neg(self) -> BoxedMontyForm {
26        BoxedMontyForm::neg(self)
27    }
28}
29
30#[cfg(test)]
31mod tests {
32    use crate::{
33        modular::{BoxedMontyForm, BoxedMontyParams},
34        BoxedUint,
35    };
36    use hex_literal::hex;
37
38    #[test]
39    fn neg_expected() {
40        let modulus = BoxedUint::from_be_slice(
41            &hex!("ffffffff00000000ffffffffffffffffbce6faada7179e84f3b9cac2fc632551"),
42            256,
43        )
44        .expect("error creating modulus");
45        let params = BoxedMontyParams::new(modulus.to_odd().unwrap());
46
47        let x = BoxedUint::from_be_slice(
48            &hex!("44acf6b7e36c1342c2c5897204fe09504e1e2efb1a900377dbc4e7a6a133ec56"),
49            256,
50        )
51        .expect("error creating boxeduint");
52        let x_mod = BoxedMontyForm::new(x, params.clone());
53
54        assert!(bool::from((x_mod.neg() + x_mod).is_zero()));
55    }
56}
crypto_bigint/modular/boxed_monty_form/neg.rs

crypto_bigint/modular/boxed_monty_form/
neg.rs
