From 5ab9d59ee19ec1a50976d98344d331015180f7c9 Mon Sep 17 00:00:00 2001
From: NIIBE Yutaka <gniibe@fsij.org>
Date: Fri, 4 Jul 2025 14:19:26 +0900
Subject: common:ecc: Have a field if the curve of ECC is Weierstrass.

* common/util.h (struct gnupg_ecc_params): Add is_weierstrauss.
* common/kem.c (ecc_table): Update.  Also add secp256k1.

--

GnuPG-bug-id: 7698
Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
---
 common/kem.c  | 26 +++++++++++++++++---------
 common/util.h |  1 +
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/common/kem.c b/common/kem.c
index 5d994f0d6..94ad13457 100644
--- a/common/kem.c
+++ b/common/kem.c
@@ -256,51 +256,59 @@ static const struct gnupg_ecc_params ecc_table[] =
       "Curve25519",
       33, 32, 32,
       GCRY_MD_SHA3_256, GCRY_KEM_RAW_X25519,
-      1, 1
+      1, 1, 0
     },
     {
       "X448",
       56, 56, 56,
       GCRY_MD_SHA3_512, GCRY_KEM_RAW_X448,
-      0, 0
+      0, 0, 0
     },
     {
       "NIST P-256",
       65, 32, 65,
       GCRY_MD_SHA3_256, GCRY_KEM_RAW_P256R1,
-      0, 0
+      0, 0, 1
     },
     {
       "NIST P-384",
       97, 48, 97,
       GCRY_MD_SHA3_512, GCRY_KEM_RAW_P384R1,
-      0, 0
+      0, 0, 1
     },
     {
       "NIST P-521",
       133, 66, 133,
       GCRY_MD_SHA3_512, GCRY_KEM_RAW_P521R1,
-      0, 0
+      0, 0, 1
     },
     {
       "brainpoolP256r1",
       65, 32, 65,
       GCRY_MD_SHA3_256, GCRY_KEM_RAW_BP256,
-      0, 0
+      0, 0, 1
     },
     {
       "brainpoolP384r1",
       97, 48, 97,
       GCRY_MD_SHA3_512, GCRY_KEM_RAW_BP384,
-      0, 0
+      0, 0, 1
     },
     {
       "brainpoolP512r1",
       129, 64, 129,
       GCRY_MD_SHA3_512, GCRY_KEM_RAW_BP512,
-      0, 0
+      0, 0, 1
     },
-    { NULL, 0, 0, 0, 0, 0, 0, 0 }
+#ifdef GCRY_KEM_RAW_P256K1
+    {
+      "secp256k1",
+      65, 32, 65,
+      GCRY_MD_SHA3_256, GCRY_KEM_RAW_P256K1,
+      0, 0, 1
+    },
+#endif
+    { NULL, 0, 0, 0, 0, 0, 0, 0, 0 }
 };
 
 
diff --git a/common/util.h b/common/util.h
index b13f4300d..e8e6ed409 100644
--- a/common/util.h
+++ b/common/util.h
@@ -335,6 +335,7 @@ struct gnupg_ecc_params
   int kem_algo;
   int scalar_reverse;     /* Byte-oder is reverse.  */
   int may_have_prefix;    /* Point representation may have prefix.  */
+  int is_weierstrauss;    /* True if it is Weierstrass curve.  */
 };
 
 const struct gnupg_ecc_params *gnupg_get_ecc_params (const char *curve);
-- 
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