mirror of
https://github.com/saymrwulf/betrusted-curve25519-dalek-source.git
synced 2026-09-04 20:24:07 +00:00
add sw fallback for montgomery routines
This commit is contained in:
bunnie
parent
077d5a1fba
commit
63a24a80b6
1 changed files with 104 additions and 52 deletions
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@ -54,10 +54,7 @@ use core::{
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ops::{Mul, MulAssign},
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};
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#[cfg(not(curve25519_dalek_backend = "u32e_backend"))]
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use crate::constants::{APLUS2_OVER_FOUR, MONTGOMERY_A, MONTGOMERY_A_NEG};
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#[cfg(curve25519_dalek_backend = "u32e_backend")]
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use crate::constants::{MONTGOMERY_A, MONTGOMERY_A_NEG}; // eliminate constants absorbed into the microcode engine
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use crate::edwards::{CompressedEdwardsY, EdwardsPoint};
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use crate::field::FieldElement;
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@ -465,15 +462,23 @@ impl ProjectivePoint {
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);
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use crate::backend::serial::u32e::*;
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ensure_engine();
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// safety: these were called after ensure_engine()
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let mut ucode_hw = unsafe { get_ucode() };
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let rf_hw = unsafe { get_rf() };
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match ensure_engine() {
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Ok(_) => {
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// safety: these were called after ensure_engine()
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let mut ucode_hw = unsafe { get_ucode() };
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let rf_hw = unsafe { get_rf() };
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copy_to_rf(self.U.as_bytes(), 29, rf_hw, 0);
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copy_to_rf(self.W.as_bytes(), 30, rf_hw, 0);
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copy_to_rf(self.U.as_bytes(), 29, rf_hw, 0);
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copy_to_rf(self.W.as_bytes(), 30, rf_hw, 0);
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MontgomeryPoint(run_job(&mut ucode_hw, &rf_hw, &mcode, 0))
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MontgomeryPoint(run_job(&mut ucode_hw, &rf_hw, &mcode, 0))
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}
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_ => {
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log::warn!("Hardware acceleration unavailable, falling back to software");
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let u = &self.U * &self.W.invert();
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MontgomeryPoint(u.as_bytes())
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}
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}
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}
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}
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@ -622,29 +627,68 @@ pub(crate) fn differential_add_and_double(
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fin // finish execution
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);
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use crate::backend::serial::u32e::*;
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ensure_engine();
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// safety: these were called after ensure_engine()
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let mut ucode_hw = unsafe { get_ucode() };
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let rf_hw = unsafe { get_rf() };
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match ensure_engine() {
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Ok(_) => {
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// safety: these were called after ensure_engine()
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let mut ucode_hw = unsafe { get_ucode() };
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let rf_hw = unsafe { get_rf() };
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// P.U in %20
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// P.W in %21
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// Q.U in %22
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// Q.W in %23
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// affine_PmQ in %24
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copy_to_rf(P.U.as_bytes(), 20, rf_hw, 0);
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copy_to_rf(P.W.as_bytes(), 21, rf_hw, 0);
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copy_to_rf(Q.U.as_bytes(), 22, rf_hw, 0);
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copy_to_rf(Q.W.as_bytes(), 23, rf_hw, 0);
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copy_to_rf(affine_PmQ.as_bytes(), 24, rf_hw, 0);
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// P.U in %20
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// P.W in %21
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// Q.U in %22
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// Q.W in %23
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// affine_PmQ in %24
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copy_to_rf(P.U.as_bytes(), 20, rf_hw, 0);
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copy_to_rf(P.W.as_bytes(), 21, rf_hw, 0);
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copy_to_rf(Q.U.as_bytes(), 22, rf_hw, 0);
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copy_to_rf(Q.W.as_bytes(), 23, rf_hw, 0);
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copy_to_rf(affine_PmQ.as_bytes(), 24, rf_hw, 0);
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// start the run
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run_job(&mut ucode_hw, &rf_hw, &mcode, 0);
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// start the run
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run_job(&mut ucode_hw, &rf_hw, &mcode, 0);
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P.U = FieldElement::from_bytes(©_from_rf(20, &rf_hw, 0));
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P.W = FieldElement::from_bytes(©_from_rf(21, &rf_hw, 0));
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Q.U = FieldElement::from_bytes(©_from_rf(22, &rf_hw, 0));
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Q.W = FieldElement::from_bytes(©_from_rf(23, &rf_hw, 0));
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P.U = FieldElement::from_bytes(©_from_rf(20, &rf_hw, 0));
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P.W = FieldElement::from_bytes(©_from_rf(21, &rf_hw, 0));
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Q.U = FieldElement::from_bytes(©_from_rf(22, &rf_hw, 0));
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Q.W = FieldElement::from_bytes(©_from_rf(23, &rf_hw, 0));
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}
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_ => {
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log::warn!("Hardware acceleration unavailable, falling back to software");
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let t0 = &P.U + &P.W;
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let t1 = &P.U - &P.W;
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let t2 = &Q.U + &Q.W;
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let t3 = &Q.U - &Q.W;
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let t4 = t0.square(); // (U_P + W_P)^2 = U_P^2 + 2 U_P W_P + W_P^2
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let t5 = t1.square(); // (U_P - W_P)^2 = U_P^2 - 2 U_P W_P + W_P^2
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let t6 = &t4 - &t5; // 4 U_P W_P
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let t7 = &t0 * &t3; // (U_P + W_P) (U_Q - W_Q) = U_P U_Q + W_P U_Q - U_P W_Q - W_P W_Q
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let t8 = &t1 * &t2; // (U_P - W_P) (U_Q + W_Q) = U_P U_Q - W_P U_Q + U_P W_Q - W_P W_Q
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let t9 = &t7 + &t8; // 2 (U_P U_Q - W_P W_Q)
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let t10 = &t7 - &t8; // 2 (W_P U_Q - U_P W_Q)
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let t11 = t9.square(); // 4 (U_P U_Q - W_P W_Q)^2
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let t12 = t10.square(); // 4 (W_P U_Q - U_P W_Q)^2
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let t13 = &APLUS2_OVER_FOUR * &t6; // (A + 2) U_P U_Q
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let t14 = &t4 * &t5; // ((U_P + W_P)(U_P - W_P))^2 = (U_P^2 - W_P^2)^2
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let t15 = &t13 + &t5; // (U_P - W_P)^2 + (A + 2) U_P W_P
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let t16 = &t6 * &t15; // 4 (U_P W_P) ((U_P - W_P)^2 + (A + 2) U_P W_P)
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let t17 = affine_PmQ * &t12; // U_D * 4 (W_P U_Q - U_P W_Q)^2
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let t18 = t11; // W_D * 4 (U_P U_Q - W_P W_Q)^2
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P.U = t14; // U_{P'} = (U_P + W_P)^2 (U_P - W_P)^2
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P.W = t16; // W_{P'} = (4 U_P W_P) ((U_P - W_P)^2 + ((A + 2)/4) 4 U_P W_P)
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Q.U = t18; // U_{Q'} = W_D * 4 (U_P U_Q - W_P W_Q)^2
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Q.W = t17; // W_{Q'} = U_D * 4 (W_P U_Q - U_P W_Q)^2
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}
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}
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}
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define_mul_assign_variants!(LHS = MontgomeryPoint, RHS = Scalar);
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@ -945,35 +989,43 @@ impl Mul<&Scalar> for &MontgomeryPoint {
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);
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let window = 0;
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ensure_engine();
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// safety: these were called after ensure_engine()
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let mut ucode_hw = unsafe { get_ucode() };
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let mut rf_hw = unsafe { get_rf() };
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match ensure_engine() {
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Ok(_) => {
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// safety: these were called after ensure_engine()
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let mut ucode_hw = unsafe { get_ucode() };
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let mut rf_hw = unsafe { get_rf() };
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copy_to_rf(x0.U.as_bytes(), 25, &mut rf_hw, window);
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copy_to_rf(x0.W.as_bytes(), 26, &mut rf_hw, window);
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copy_to_rf(x1.U.as_bytes(), 27, &mut rf_hw, window);
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copy_to_rf(x1.W.as_bytes(), 28, &mut rf_hw, window);
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copy_to_rf(affine_u.as_bytes(), 24, &mut rf_hw, window);
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copy_to_rf(scalar.bytes, 31, &mut rf_hw, window);
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copy_to_rf(
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[
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254, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00,
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],
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19,
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&mut rf_hw,
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window,
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); // 254 as loop counter
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copy_to_rf(x0.U.as_bytes(), 25, &mut rf_hw, window);
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copy_to_rf(x0.W.as_bytes(), 26, &mut rf_hw, window);
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copy_to_rf(x1.U.as_bytes(), 27, &mut rf_hw, window);
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copy_to_rf(x1.W.as_bytes(), 28, &mut rf_hw, window);
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copy_to_rf(affine_u.as_bytes(), 24, &mut rf_hw, window);
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copy_to_rf(scalar.bytes, 31, &mut rf_hw, window);
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copy_to_rf(
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[
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254, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00,
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],
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19,
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&mut rf_hw,
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window,
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); // 254 as loop counter
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MontgomeryPoint(run_job(&mut ucode_hw, &rf_hw, &mcode, window))
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MontgomeryPoint(run_job(&mut ucode_hw, &rf_hw, &mcode, window))
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}
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_ => {
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log::warn!("Hardware acceleration unavailable, falling back to software");
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// We multiply by the integer representation of the given Scalar. By scalar invariant #1,
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// the MSB is 0, so we can skip it.
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self.mul_bits_be(scalar.bits_le().rev().skip(1))
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}
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}
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}
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/// Given `self` \\( = u\_0(P) \\), and a `Scalar` \\(n\\), return \\( u\_0(\[n\]P) \\)
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#[cfg(not(curve25519_dalek_backend = "u32e_backend"))]
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fn mul(self, scalar: &Scalar) -> MontgomeryPoint {
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// TODO: consider feature "panic_on_sw_eval"
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#[cfg(all(not(test), curve25519_dalek_backend = "u32e_backend"))] // due to issue https://github.com/rust-lang/rust/issues/59168, you will have to manually comment this out when running a test on the full system and not just this crate.
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log::warn!("sw montgomery multiply being used - check for build config errors!");
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// We multiply by the integer representation of the given Scalar. By scalar invariant #1,
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