我有一个 DER 编码的 CMS 文件,我想使用 openssl API 对其进行解密。
我找到了API用于解密:
CMS_decrypt(cms_content, pkey, cert, NULL, out, NULL);
我找到了读取 pkey 和 cert PEM 文件以及设置输出 BIO 的示例,但我不知道如何读取 cms 文件。
问题:如何将 ASN.1 DER 编码文件读取到类型为 CMS_ContentInfo
的 cms_content
变量中?
编辑:感谢 Camille's answer ,我设法让它工作:
#include <stdio.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
#include <openssl/cms.h>
int main (int argc, char **argv)
{
char pkeypath[] = "recipient_prvkey.pem";
char certpath[] = "sender_cert.pem";
char cmspath[] = "encrypted.der";
char decpath[] = "decrypted.zip";
BIO *in = NULL, *out = NULL, *tbio = NULL;
CMS_ContentInfo *cms = NULL;
EVP_PKEY *pkey;
X509 *cert;
OpenSSL_add_all_algorithms();
ERR_load_crypto_strings();
tbio = BIO_new_file(pkeypath, "r");
pkey = PEM_read_bio_PrivateKey(tbio, NULL, 0, NULL);
if (pkey == NULL) {
printf("error reading private key");
return EXIT_FAILURE;
}
BIO_free(tbio);
tbio = BIO_new_file(certpath, "r");
cert = PEM_read_bio_X509(tbio, NULL, 0, NULL);
if (cert == NULL) {
printf("error reading private key");
return EXIT_FAILURE;
}
in = BIO_new_file(cmspath, "r");
cms = d2i_CMS_bio(in, NULL);
BIO_free(in);
out = BIO_new_file(decpath, "w");
if (!CMS_decrypt_set1_pkey(cms, pkey, cert))
{
fprintf(stderr, "set1_pkey error\n");
return EXIT_FAILURE;
}
if (!CMS_decrypt(cms, NULL, NULL, NULL, out, CMS_BINARY))
{
int error = ERR_get_error();
fprintf(stderr, "error: %s :: %s :: %s\n",
ERR_reason_error_string(error),
ERR_func_error_string(error),
ERR_lib_error_string(error)
);
}
BIO_free(out);
return 0;
}
最佳答案
我刚刚复制了与 PEM 配合使用的 OpenSSL cms_dec 示例,并将其改编为 DER 编码的 CMS 文件
BIO *in = NULL, *out = NULL, *tbio = NULL;
X509 *cert= 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("yourCMS.der", "r");
rcert = i2d_x509_bio(tbio, NULL);
BIO_reset(tbio);
i2d_PrivateKey_bio(tbio, rkey);
/* Open S/MIME message to decrypt */
in = BIO_new_file("smencr.txt", "r");
/* Parse message */
cms = SMIME_read_CMS(in, NULL);
out = BIO_new_file("decout.txt", "w");
/* Decrypt S/MIME message */
CMS_decrypt(cms, rkey, rcert, out, NULL, CMS_BINARY) //Edit : Added Flags for DER.
...
关于c - 如何使用 openssl API 解密 ASN.1 DER 编码的 CMS 文件?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/19235793/