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Add RSA key generation example
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Lines changed: 269 additions & 4 deletions

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‎.gitignore‎

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@@ -220,6 +220,7 @@ pk/ed25519_gen/gen_key_files
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pk/ed25519_gen/sign_and_verify
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pk/ecdh_generate_secret/ecdh_gen_secret
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pk/rsa-kg/rsa-kg-sv
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pk/rsa-kg/rsa-kg
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pk/dh-pg/dh-pg-ka
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pk/test_cert_and_private_keypair/test-cert-privkey-pair
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pk/srp/srp_gen

‎pk/rsa-kg/Makefile‎

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@@ -2,15 +2,21 @@ CC=gcc
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CFLAGS=-Wall
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LIBS= -lwolfssl -lm
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all: rsa-kg-sv
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all: rsa-kg-sv rsa-kg
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rsa-kg-sv.o: rsa-kg-sv.c rsa-key.h
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$(CC) -c -o $@ $< $(CFLAGS)
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rsa-kg-sv: rsa-kg-sv.o
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$(CC) -o $@ $^ $(CFLAGS) $(LIBS)
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$(CC) -o $@ $^ $(CFLAGS) $(LIBS)
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rsa-kg.o: rsa-kg.c
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$(CC) -c -o $@ $< $(CFLAGS)
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rsa-kg: rsa-kg.o
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$(CC) -o $@ $^ $(CFLAGS) $(LIBS)
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.PHONY: clean
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clean:
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rm -f *.o rsa-kg-sv
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rm -f *.o rsa-kg-sv rsa-kg

‎pk/rsa-kg/README.md‎

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@@ -13,6 +13,21 @@ How to use rsa-kg-sv.c
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NOTE: on error, the key and digest will be displayed so that they can be
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copied into rsa-key.h replacing the existing values.
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4) Running 'make clean' will delete the executable and object files.
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3) Running 'make clean' will delete the executable and object files.
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How to use rsa-kg.c
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1) a. Compile wolfSSL with ./configure --enable-keygen, run
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'make', and then install by typing 'sudo make install'.
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b. In the pk/rsa-kg directory run the Makefile by typing 'make'.
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2) run the executable, for help run with -help. Basic command is as follows:
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./rsa-kg <options>
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Key sizes supported, in bits: 1024-4096.
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Specify the name of the output files with -priv and -pub.
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3) Running 'make clean' will delete the executable and object files.
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‎pk/rsa-kg/rsa-kg.c‎

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/* rsa-kg.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.
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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 02110-1335, USA
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*/
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/*
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* An implementation of RSA key generation using wolfSSL
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* Usage:
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./rsa-kg -priv <private key filename> -pub <public key filename>
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*/
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#include <stdio.h>
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#include <string.h>
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#include <wolfssl/options.h>
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#include <wolfssl/wolfcrypt/settings.h>
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#include <wolfssl/ssl.h>
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#include <wolfssl/wolfcrypt/rsa.h>
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#include <wolfssl/wolfcrypt/error-crypt.h>
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#define MAX_DER_SIZE 2500
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#define MIN_RSA_KEY_SIZE 1024
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#define MAX_RSA_KEY_SIZE 4096
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#define DEF_RSA_KEY_SIZE 2048
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static const char* kRsaPubKey = "./rsa-public.der";
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static const char* kRsaPrivKey = "./rsa-private.der";
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/* Shows usage information */
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void usage()
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{
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fprintf(stderr, "rsa_kg <options>:\n");
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fprintf(stderr, " -bits <num> Size in bits of RSA keys generated\n");
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fprintf(stderr, " Range: 1024-4096\n");
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fprintf(stderr, " -priv <filename> Private key filename\n");
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fprintf(stderr, " -pub <filename> Public key filename\n");
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fprintf(stderr, "\n");
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}
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int main(int argc, char** argv)
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{
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/* These examples require RSA and Key Gen */
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#if !defined(NO_RSA) && defined(WOLFSSL_KEY_GEN)
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RsaKey* pRsaKey = NULL;
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WC_RNG rng;
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int ret = 0;
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int bits = DEF_RSA_KEY_SIZE;
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int sz;
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unsigned char derBuf[MAX_DER_SIZE];
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FILE* f;
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const char* pubKey = kRsaPubKey;
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const char* privKey = kRsaPrivKey;
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argc--;
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argv++;
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while (argc > 0) {
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/* Number of bits in RSA key to generate */
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if (XSTRNCMP(*argv, "-bits", 6) == 0) {
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++argv;
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if (--argc == 0) {
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fprintf(stderr, "Missing bits value\n");
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usage();
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return 1;
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}
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bits = atoi(*argv);
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}
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else if (XSTRNCMP(*argv, "-priv", 6) == 0) {
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++argv;
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if (--argc == 0) {
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fprintf(stderr, "Missing private key filename\n");
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usage();
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return 1;
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}
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privKey = *argv;
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}
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else if (XSTRNCMP(*argv, "-pub", 6) == 0) {
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++argv;
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if (--argc == 0) {
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fprintf(stderr, "Missing public key filename\n");
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usage();
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return 1;
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}
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pubKey = *argv;
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}
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else if (XSTRNCMP(*argv, "-help", 6) == 0) {
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usage();
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return 0;
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}
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else {
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fprintf(stderr, "Unrecognized option: %s\n", *argv);
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usage();
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return 1;
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}
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argc--;
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argv++;
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}
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/* Check bit count if generating keys */
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if ((bits < MIN_RSA_KEY_SIZE || bits > MAX_RSA_KEY_SIZE)) {
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fprintf(stderr, "Bits out of range (%d-%d): %d\n", MIN_RSA_KEY_SIZE,
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MAX_RSA_KEY_SIZE, bits);
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usage();
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return 1;
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}
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#ifdef WOLFSSL_SP_MATH
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if (0) {
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}
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#ifndef WOLFSSL_SP_NO_2048
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else if (bits == 2048) {
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}
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#endif
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#ifndef WOLFSSL_SP_NO_3072
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else if (bits == 3072) {
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}
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#endif
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#ifdef WOLFSSL_SP_4096
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else if (bits == 4096) {
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}
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#endif
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else {
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fprintf(stderr, "Bit size not supported with SP_MATH: %d\n", bits);
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fprintf(stderr, " wolfSSL compiled to support, in bits:");
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#ifndef WOLFSSL_SP_NO_2048
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fprintf(stderr, " 2048");
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#endif
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#ifndef WOLFSSL_SP_NO_3072
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fprintf(stderr, " 3072");
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#endif
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#ifdef WOLFSSL_SP_4096
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fprintf(stderr, " 4096");
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#endif
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fprintf(stderr, "\n");
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return 1;
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}
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#endif
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wolfSSL_Debugging_ON();
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wolfSSL_Init();
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/* Allocate space for RSA key object. */
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pRsaKey = malloc(sizeof(RsaKey));
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if (!pRsaKey) {
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printf("RSA_generate_key failed with error\n");
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return MEMORY_E;
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}
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/* Create a random number generator for key generation. */
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ret = wc_InitRng(&rng);
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if (ret != 0) {
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printf("Init RNG failed %d\n", ret);
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free(pRsaKey);
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return ret;
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}
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/* Initialize RSA key object. */
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ret = wc_InitRsaKey(pRsaKey, NULL);
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if (ret != 0) {
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printf("Init RSA key failed %d\n", ret);
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wc_FreeRng(&rng);
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free(pRsaKey);
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return ret;
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}
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printf("Generating RSA key\n");
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/* Generate an RSA key pair. */
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if (wc_MakeRsaKey(pRsaKey, bits, WC_RSA_EXPONENT, &rng) != 0) {
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printf("failed to create rsa key\n");
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}
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else {
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/* Open public key file. */
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f = fopen(pubKey, "wb");
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printf("writing public key to %s\n", pubKey);
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if (f == NULL) {
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printf("unable to write out public key\n");
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}
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else {
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/* Encode public key to DER. */
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sz = wc_RsaKeyToPublicDer(pRsaKey, derBuf, sizeof(derBuf));
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if (sz <= 0) {
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printf("error with rsa to public der %d\n", sz);
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}
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else {
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/* Write DER encoded public key to file. */
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fwrite(derBuf, 1, sz, f);
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}
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fclose(f);
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}
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/* Open private key file. */
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f = fopen(privKey, "wb");
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printf("writing public key to %s\n", privKey);
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if (f == NULL) {
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printf("unable to write out public key\n");
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}
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else {
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/* Encode private key to DER. */
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sz = wc_RsaKeyToDer(pRsaKey, derBuf, sizeof(derBuf));
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if (sz <= 0) {
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printf("error with rsa to public der %d\n", sz);
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}
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else {
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/* Write DER encoded private key to file. */
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fwrite(derBuf, 1, sz, f);
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}
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fclose(f);
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}
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}
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/* Dispose of allocated memory. */
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wc_FreeRsaKey(pRsaKey);
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wc_FreeRng(&rng);
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free(pRsaKey);
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wolfSSL_Cleanup();
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return 0;
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#else
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(void)kRsaPubKey;
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(void)kRsaPrivKey;
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printf("wolfSSL missing build features.\n");
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printf("Please build using `./configure --enable-keygen`\n");
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return 1;
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#endif
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}

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