/*

 * Copyright 2008-2016 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

/* Simple S/MIME decryption example */

#include <openssl/pem.h>

#include <openssl/cms.h>

#include <openssl/err.h>

int main(int argc, char **argv)

{

    BIO *in = NULL, *out = NULL, *tbio = NULL;

    X509 *rcert = NULL;

    EVP_PKEY *rkey = NULL;

    CMS_ContentInfo *cms = NULL;

    int ret = 1;

    OpenSSL_add_all_algorithms();

    ERR_load_crypto_strings();

    /* Read in recipient certificate and private key */

    tbio = BIO_new_file("signer.pem", "r");

    if (!tbio)

        goto err;

    rcert = PEM_read_bio_X509(tbio, NULL, 0, NULL);

    BIO_reset(tbio);

    rkey = PEM_read_bio_PrivateKey(tbio, NULL, 0, NULL);

    if (!rcert || !rkey)

        goto err;

    /* Open S/MIME message to decrypt */

    in = BIO_new_file("smencr.txt", "r");

    if (!in)

        goto err;

    /* Parse message */

    cms = SMIME_read_CMS(in, NULL);

    if (!cms)

        goto err;

    out = BIO_new_file("decout.txt", "w");

    if (!out)

        goto err;

    /* Decrypt S/MIME message */

    if (!CMS_decrypt(cms, rkey, rcert, NULL, out, 0))

        goto err;

    ret = 0;

 err:

    if (ret) {

        fprintf(stderr, "Error Decrypting Data\n");

        ERR_print_errors_fp(stderr);

    }

    CMS_ContentInfo_free(cms);

    X509_free(rcert);

    EVP_PKEY_free(rkey);

    BIO_free(in);

    BIO_free(out);

    BIO_free(tbio);

    return ret;

}