openssl3.2 - 官方demo学习 - smime - smsign.c

openssl3.2 - 官方demo学习 - smime - smsign.c

概述

从证书中得到X509*和私钥指针
用证书和私钥对铭文进行签名, 得到签名后的pkcs7指针
将pkcs7指向的bio_in, 写为MIME格式的签名密文

BIO_reset() 可以将一个bio恢复到刚打开的状态(应该就是将文件指针重新指向文件头部), 一般用于只读打开的场景
经常用于多个对象要操作同一个bio的场景(一先一后的操作).

笔记

/*!
\file smsign.c
\note 
openssl3.2 - 官方demo学习 - smime - smsign.c从证书中得到X509*和私钥指针
用证书和私钥对铭文进行签名, 得到签名后的pkcs7指针
将pkcs7指向的bio_in, 写为MIME格式的签名密文BIO_reset() 可以将一个bio恢复到刚打开的状态(应该就是将文件指针重新指向文件头部), 一般用于只读打开的场景
经常用于多个对象要操作同一个bio的场景(一先一后的操作).
*//** Copyright 2007-2023 The OpenSSL Project Authors. All Rights Reserved.** Licensed under the Apache License 2.0 (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 signing example */
#include <openssl/pem.h>
#include <openssl/pkcs7.h>
#include <openssl/err.h>#include "my_openSSL_lib.h"int main(int argc, char **argv)
{BIO *_bio_in = NULL, *_bio_out = NULL, *_bio_t = NULL;X509 *_x509 = NULL;EVP_PKEY *_evp_pkey = NULL;PKCS7 *_pkcs7 = NULL;int ret = EXIT_FAILURE;/** For simple S/MIME signing use PKCS7_DETACHED. On OpenSSL 0.9.9 only:* for streaming detached set PKCS7_DETACHED|PKCS7_STREAM for streaming* non-detached set PKCS7_STREAM*/int flags = PKCS7_DETACHED | PKCS7_STREAM;OpenSSL_add_all_algorithms();ERR_load_crypto_strings();/* Read in signer certificate and private key */_bio_t = BIO_new_file("signer.pem", "r");if (!_bio_t)goto err;_x509 = PEM_read_bio_X509(_bio_t, NULL, 0, NULL);BIO_reset(_bio_t);_evp_pkey = PEM_read_bio_PrivateKey(_bio_t, NULL, 0, NULL);if (!_x509 || !_evp_pkey)goto err;/* Open content being signed */_bio_in = BIO_new_file("sign.txt", "r");if (!_bio_in)goto err;/* Sign content */_pkcs7 = PKCS7_sign(_x509, _evp_pkey, NULL, _bio_in, flags);if (!_pkcs7)goto err;_bio_out = BIO_new_file("smout.txt", "w");if (!_bio_out)goto err;if (!(flags & PKCS7_STREAM))BIO_reset(_bio_in);/* Write out S/MIME message */if (!SMIME_write_PKCS7(_bio_out, _pkcs7, _bio_in, flags))goto err;ret = EXIT_SUCCESS;err:if (ret != EXIT_SUCCESS) {fprintf(stderr, "Error Signing Data\n");ERR_print_errors_fp(stderr);}PKCS7_free(_pkcs7);X509_free(_x509);EVP_PKEY_free(_evp_pkey);BIO_free(_bio_in);BIO_free(_bio_out);BIO_free(_bio_t);return ret;}

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