From 2aadc03ef15cb5ca5cc2af8a7c08e070742f0ac4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 4 May 2024 14:47:55 +0200 Subject: Adding upstream version 0.70.1+ds1. Signed-off-by: Daniel Baumann --- vendor/crypto-bigint/src/limb/rand.rs | 38 +++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 vendor/crypto-bigint/src/limb/rand.rs (limited to 'vendor/crypto-bigint/src/limb/rand.rs') diff --git a/vendor/crypto-bigint/src/limb/rand.rs b/vendor/crypto-bigint/src/limb/rand.rs new file mode 100644 index 0000000..4347168 --- /dev/null +++ b/vendor/crypto-bigint/src/limb/rand.rs @@ -0,0 +1,38 @@ +//! Random number generator support + +use super::Limb; +use crate::{Encoding, NonZero, Random, RandomMod}; +use rand_core::CryptoRngCore; +use subtle::ConstantTimeLess; + +impl Random for Limb { + #[cfg(target_pointer_width = "32")] + fn random(rng: &mut impl CryptoRngCore) -> Self { + Self(rng.next_u32()) + } + + #[cfg(target_pointer_width = "64")] + fn random(rng: &mut impl CryptoRngCore) -> Self { + Self(rng.next_u64()) + } +} + +impl RandomMod for Limb { + fn random_mod(rng: &mut impl CryptoRngCore, modulus: &NonZero) -> Self { + let mut bytes = ::Repr::default(); + + let n_bits = modulus.bits(); + let n_bytes = (n_bits + 7) / 8; + let mask = 0xff >> (8 * n_bytes - n_bits); + + loop { + rng.fill_bytes(&mut bytes[..n_bytes]); + bytes[n_bytes - 1] &= mask; + + let n = Limb::from_le_bytes(bytes); + if n.ct_lt(modulus).into() { + return n; + } + } + } +} -- cgit v1.2.3