crypto-bigint 0.7.3

Pure Rust implementation of a big integer library which has been designed from the ground-up for use in cryptographic applications. Provides constant-time, no_std-friendly implementations of modern formulas using const generics.
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

//! [`BoxedUint`] bitwise XOR operations.

use super::BoxedUint;
use crate::{BitXor, BitXorAssign, CtOption};

impl BoxedUint {
    /// Computes bitwise `a ^ b`.
    #[inline(always)]
    #[must_use]
    pub fn bitxor(&self, rhs: &Self) -> Self {
        Self::map_limbs(self, rhs, crate::limb::Limb::bitxor)
    }

    /// Perform wrapping bitwise `XOR`.
    ///
    /// There's no way wrapping could ever happen.
    /// This function exists so that all operations are accounted for in the wrapping operations
    #[must_use]
    pub fn wrapping_xor(&self, rhs: &Self) -> Self {
        self.bitxor(rhs)
    }

    /// Perform checked bitwise `XOR`, returning a [`CtOption`] which `is_some` always
    #[must_use]
    pub fn checked_xor(&self, rhs: &Self) -> CtOption<Self> {
        CtOption::some(self.bitxor(rhs))
    }
}

impl BitXor for BoxedUint {
    type Output = Self;

    fn bitxor(self, rhs: Self) -> BoxedUint {
        self.bitxor(&rhs)
    }
}

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

    fn bitxor(self, rhs: &BoxedUint) -> BoxedUint {
        Self::bitxor(&self, rhs)
    }
}

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

    fn bitxor(self, rhs: BoxedUint) -> BoxedUint {
        self.bitxor(&rhs)
    }
}

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

    fn bitxor(self, rhs: &BoxedUint) -> BoxedUint {
        self.bitxor(rhs)
    }
}

impl BitXorAssign for BoxedUint {
    fn bitxor_assign(&mut self, other: Self) {
        *self = Self::bitxor(self, &other);
    }
}

impl BitXorAssign<&BoxedUint> for BoxedUint {
    fn bitxor_assign(&mut self, other: &Self) {
        *self = Self::bitxor(self, other);
    }
}

#[cfg(test)]
mod tests {
    use crate::U128;

    #[test]
    fn checked_xor_ok() {
        let result = U128::ZERO.checked_xor(&U128::ONE);
        assert_eq!(result.unwrap(), U128::ONE);
    }

    #[test]
    fn overlapping_xor_ok() {
        let result = U128::ZERO.wrapping_xor(&U128::ONE);
        assert_eq!(result, U128::ONE);
    }
}