45 lines
1.5 KiB
Diff
45 lines
1.5 KiB
Diff
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From 401c8d53d8a8cf1e79980e62bda3f946f8e07c14 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Niels=20M=C3=B6ller?= <nisse@lysator.liu.se>
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Date: Sat, 13 Mar 2021 16:29:50 +0100
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Subject: [PATCH] Analogous fix to ecc_gostdsa_verify.
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* ecc-gostdsa-verify.c (ecc_gostdsa_verify): Use ecc_mod_mul_canonical
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to compute the scalars used for ecc multiplication.
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(cherry picked from commit fbaefb64b90cb45b7075a0ed72a92f2a1fbcd2ab)
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---
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ChangeLog | 3 +++
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ecc-gostdsa-verify.c | 6 +++---
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2 files changed, 6 insertions(+), 3 deletions(-)
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#diff --git a/ChangeLog b/ChangeLog
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#index fb2d7f66..5f8a22c2 100644
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#--- a/ChangeLog
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#+++ b/ChangeLog
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#@@ -1,5 +1,8 @@
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# 2021-03-13 Niels Möller <nisse@lysator.liu.se>
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#
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#+ * ecc-gostdsa-verify.c (ecc_gostdsa_verify): Use ecc_mod_mul_canonical
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#+ to compute the scalars used for ecc multiplication.
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#+
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# * ecc-ecdsa-sign.c (ecc_ecdsa_sign): Ensure s output is reduced to
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# canonical range.
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#
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--- a/ecc-gostdsa-verify.c
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+++ b/ecc-gostdsa-verify.c
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@@ -102,11 +102,11 @@ ecc_gostdsa_verify (const struct ecc_cur
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ecc->q.invert (&ecc->q, vp, hp, vp + 2*ecc->p.size);
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/* z1 = s / h, P1 = z1 * G */
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- ecc_mod_mul (&ecc->q, z1, sp, vp);
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+ ecc_mod_mul_canonical (&ecc->q, z1, sp, vp, z1);
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/* z2 = - r / h, P2 = z2 * Y */
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- ecc_mod_mul (&ecc->q, z2, rp, vp);
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- mpn_sub_n (z2, ecc->q.m, z2, ecc->p.size);
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+ mpn_sub_n (hp, ecc->q.m, rp, ecc->p.size);
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+ ecc_mod_mul_canonical (&ecc->q, z2, hp, vp, z2);
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/* Total storage: 5*ecc->p.size + ecc->mul_itch */
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ecc->mul (ecc, P2, z2, pp, z2 + ecc->p.size);
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