107 lines
3.0 KiB
C
107 lines
3.0 KiB
C
/* ecc_pub.c
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*
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* Copyright (C) 2006-2020 wolfSSL Inc.
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*
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* This file is part of wolfSSL. (formerly known as CyaSSL)
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*
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* wolfSSL is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* wolfSSL is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
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*/
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/* example code for extracting public from private */
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/*
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./configure && make && sudo make install
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gcc -lwolfssl -o ecc_pub ecc_pub.c
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*/
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#ifndef WOLFSSL_USER_SETTINGS
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#include <wolfssl/options.h>
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#endif
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#include <wolfssl/wolfcrypt/settings.h>
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#include <wolfssl/wolfcrypt/ecc.h>
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#include <wolfssl/wolfcrypt/logging.h>
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#include <stdint.h>
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#include <stdio.h>
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#define ECC_CURVE_SZ 32 /* SECP256R1 curve size in bytes */
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#define ECC_CURVE_ID ECC_SECP256R1
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/* Private key "d" only */
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static const uint8_t kPrivKey[] = {
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/* d */
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0x1e, 0xe7, 0x70, 0x07, 0xd3, 0x30, 0x94, 0x39,
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0x28, 0x90, 0xdf, 0x23, 0x88, 0x2c, 0x4a, 0x34,
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0x15, 0xdb, 0x4c, 0x43, 0xcd, 0xfa, 0xe5, 0x1f,
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0x3d, 0x4c, 0x37, 0xfe, 0x59, 0x3b, 0x96, 0xd8
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};
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static void print_hex(uint8_t* data, int sz)
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{
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int i;
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for (i = 0; i < sz; i++) {
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printf("%02X ", data[i]);
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if (i > 0 && ((i+1) % 16) == 0)
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printf("\n");
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}
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printf("\n");
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}
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int main()
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{
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#if defined(HAVE_ECC) && defined(HAVE_ECC_KEY_EXPORT)
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int ret;
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ecc_key ecc;
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uint8_t pubKey[ECC_CURVE_SZ*2];
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uint32_t pubQxSz = ECC_CURVE_SZ, pubQySz = ECC_CURVE_SZ;
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/* Setup the ECC key */
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ret = wc_ecc_init(&ecc);
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if (ret < 0) {
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return ret;
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}
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memset(pubKey, 0, sizeof(pubKey));
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/* Import private key "k" */
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ret = wc_ecc_import_private_key_ex(
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kPrivKey, sizeof(kPrivKey), /* private key "d" */
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NULL, 0, /* public (optional) */
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&ecc,
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ECC_CURVE_ID
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);
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/* Export public key */
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if (ret == 0) {
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ret = wc_ecc_make_pub(&ecc, NULL);
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}
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if (ret == 0) {
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ret = wc_ecc_export_public_raw(&ecc,
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pubKey, &pubQxSz, /* public Qx */
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pubKey+ECC_CURVE_SZ, &pubQySz /* public Qy */
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);
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}
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printf("Public Key Qx: %d\n", pubQxSz);
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print_hex(pubKey, ECC_CURVE_SZ);
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printf("Public Key Qy: %d\n", pubQySz);
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print_hex(pubKey+ECC_CURVE_SZ, ECC_CURVE_SZ);
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wc_ecc_free(&ecc);
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return ret;
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#else
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printf("wolfSSL needs to be built with ECC and key export enabled\n");
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return -1;
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#endif /* HAVE_ECC && HAVE_ECC_KEY_EXPORT */
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} |