From 2fd78f6d402cc7a488ac7c248e3b5ab6396747c4 Mon Sep 17 00:00:00 2001
From: Daniele Lacamera <dan@danielinux.net>
Date: Wed, 29 Jul 2020 16:47:56 +0200
Subject: [PATCH] Added ecc/ecc-export-Qx-Qy example program

---
 .gitignore             |  1 +
 ecc/Makefile           |  2 +-
 ecc/ecc-export-Qx-Qy.c | 83 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 85 insertions(+), 1 deletion(-)
 create mode 100644 ecc/ecc-export-Qx-Qy.c

diff --git a/.gitignore b/.gitignore
index 30918763..e927ae87 100644
--- a/.gitignore
+++ b/.gitignore
@@ -125,6 +125,7 @@ ecc/ecc-params
 ecc/ecc-sign
 ecc/ecc-stack
 ecc/ecc-verify
+ecc/ecc-export-Qx-Qy
 ecc/*.der
 ecc/*.pem
 pkcs7/pkcs7-verify
diff --git a/ecc/Makefile b/ecc/Makefile
index 94df7053..a6edab2e 100644
--- a/ecc/Makefile
+++ b/ecc/Makefile
@@ -5,7 +5,7 @@ CFLAGS   = -Wall -I$(LIB_PATH)/include
 LIBS     = -L$(LIB_PATH)/lib -lm
 
 # option variables
-DYN_LIB         = -lwolfssl
+DYN_LIB         = -lwolfssl -pthread
 STATIC_LIB      = $(LIB_PATH)/lib/libwolfssl.a
 DEBUG_FLAGS     = -g -DDEBUG
 DEBUG_INC_PATHS = -MD
diff --git a/ecc/ecc-export-Qx-Qy.c b/ecc/ecc-export-Qx-Qy.c
new file mode 100644
index 00000000..f93c3128
--- /dev/null
+++ b/ecc/ecc-export-Qx-Qy.c
@@ -0,0 +1,83 @@
+/* ecc-export-Qx-Qy.c
+ *
+ * Copyright (C) 2006-2020 wolfSSL Inc.
+ *
+ * This file is part of wolfSSL.
+ *
+ * wolfSSL is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * wolfSSL is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
+ */
+
+/* This example exports the public part of a given ECC key as a concatenation of
+ * (Qx,Qy), in raw format.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <wolfssl/options.h>
+#include <wolfssl/wolfcrypt/settings.h>
+#include <wolfssl/wolfcrypt/ecc.h>
+#include <wolfssl/wolfcrypt/asn.h>
+
+#define MAX_BUF 1024
+#define POINT_SIZE 32
+
+
+int main(int argc, char *argv[])
+{
+    int fd_in, fd_out, sz, ret;
+    uint8_t der_buf[MAX_BUF];
+    uint8_t Qx[POINT_SIZE], Qy[POINT_SIZE];
+    uint32_t qxlen = POINT_SIZE, qylen = POINT_SIZE;
+    word32 idx = 0;
+    ecc_key ec;
+    if (argc != 3) {
+        fprintf(stderr, "Usage: %s der_key_file raw_key_file\n", argv[0]);
+        exit(1);
+    }
+    fd_in = open(argv[1], O_RDONLY);
+    if (fd_in < 0) {
+        perror("opening input file");
+        exit(2);
+    }
+    sz = read(fd_in, der_buf, MAX_BUF);
+    if (sz < 0) {
+        perror("read");
+        exit(3);
+    }
+    close(fd_in);
+    wc_ecc_init(&ec);
+    ret = wc_EccPublicKeyDecode(der_buf, &idx, &ec, sz);
+    if (ret != MP_OKAY) {
+        fprintf(stderr, "wc_EccPublicKeyDecode: Error %d\n", ret);
+        exit(4);
+    }
+    ret = wc_ecc_export_public_raw(&ec, Qx, &qxlen, Qy, &qylen);
+    if (ret != MP_OKAY) {
+        fprintf(stderr, "wc_ecc_export_public_raw: Error %d\n", ret);
+        exit(4);
+    }
+    fd_out = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC, 0660);
+    if (fd_out < 0) {
+        perror("opening output file");
+        exit(5);
+    }
+    write(fd_out, Qx, qxlen);
+    write(fd_out, Qy, qylen);
+    close(fd_out);
+    return 0;
+}