openssl/demos/sign/sign.c

/* demos/sign/sign.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

/*
 * sign-it.cpp - Simple test app using SSLeay envelopes to sign data
 * 29.9.1996, Sampo Kellomaki <sampo@iki.fi>
 */

/* converted to C - eay :-) */

/*
 * reformated a bit and converted to use the more common functions: this was
 * initially written at the dawn of time :-) - Steve.
 */

#include <stdio.h>
#include <openssl/rsa.h>
#include <openssl/evp.h>
#include <openssl/objects.h>
#include <openssl/x509.h>
#include <openssl/err.h>
#include <openssl/pem.h>
#include <openssl/ssl.h>

int main()
{
    int err;
    int sig_len;
    unsigned char sig_buf[4096];
    static char certfile[] = "cert.pem";
    static char keyfile[] = "key.pem";
    static char data[] = "I owe you...";
    EVP_MD_CTX md_ctx;
    EVP_PKEY *pkey;
    FILE *fp;
    X509 *x509;

    /*
     * Just load the crypto library error strings, SSL_load_error_strings()
     * loads the crypto AND the SSL ones
     */
    /* SSL_load_error_strings(); */
    ERR_load_crypto_strings();

    /* Read private key */

    fp = fopen(keyfile, "r");
    if (fp == NULL)
        exit(1);
    pkey = PEM_read_PrivateKey(fp, NULL, NULL, NULL);
    fclose(fp);

    if (pkey == NULL) {
        ERR_print_errors_fp(stderr);
        exit(1);
    }

    /* Do the signature */

    EVP_SignInit(&md_ctx, EVP_sha1());
    EVP_SignUpdate(&md_ctx, data, strlen(data));
    sig_len = sizeof(sig_buf);
    err = EVP_SignFinal(&md_ctx, sig_buf, &sig_len, pkey);

    if (err != 1) {
        ERR_print_errors_fp(stderr);
        exit(1);
    }

    EVP_PKEY_free(pkey);

    /* Read public key */

    fp = fopen(certfile, "r");
    if (fp == NULL)
        exit(1);
    x509 = PEM_read_X509(fp, NULL, NULL, NULL);
    fclose(fp);

    if (x509 == NULL) {
        ERR_print_errors_fp(stderr);
        exit(1);
    }

    /* Get public key - eay */
    pkey = X509_get_pubkey(x509);
    if (pkey == NULL) {
        ERR_print_errors_fp(stderr);
        exit(1);
    }

    /* Verify the signature */

    EVP_VerifyInit(&md_ctx, EVP_sha1());
    EVP_VerifyUpdate(&md_ctx, data, strlen((char *)data));
    err = EVP_VerifyFinal(&md_ctx, sig_buf, sig_len, pkey);
    EVP_PKEY_free(pkey);

    if (err != 1) {
        ERR_print_errors_fp(stderr);
        exit(1);
    }
    printf("Signature Verified Ok.\n");
    return (0);
}