1/*
2 * S/MIME detached data decrypt example: rarely done but should the need
3 * arise this is an example....
4 */
5#include <openssl/pem.h>
6#include <openssl/cms.h>
7#include <openssl/err.h>
8
9int main(int argc, char **argv)
10{
11    BIO *in = NULL, *out = NULL, *tbio = NULL, *dcont = NULL;
12    X509 *rcert = NULL;
13    EVP_PKEY *rkey = NULL;
14    CMS_ContentInfo *cms = NULL;
15    int ret = 1;
16
17    OpenSSL_add_all_algorithms();
18    ERR_load_crypto_strings();
19
20    /* Read in recipient certificate and private key */
21    tbio = BIO_new_file("signer.pem", "r");
22
23    if (!tbio)
24        goto err;
25
26    rcert = PEM_read_bio_X509(tbio, NULL, 0, NULL);
27
28    BIO_reset(tbio);
29
30    rkey = PEM_read_bio_PrivateKey(tbio, NULL, 0, NULL);
31
32    if (!rcert || !rkey)
33        goto err;
34
35    /* Open PEM file containing enveloped data */
36
37    in = BIO_new_file("smencr.pem", "r");
38
39    if (!in)
40        goto err;
41
42    /* Parse PEM content */
43    cms = PEM_read_bio_CMS(in, NULL, 0, NULL);
44
45    if (!cms)
46        goto err;
47
48    /* Open file containing detached content */
49    dcont = BIO_new_file("smencr.out", "rb");
50
51    if (!in)
52        goto err;
53
54    out = BIO_new_file("encrout.txt", "w");
55    if (!out)
56        goto err;
57
58    /* Decrypt S/MIME message */
59    if (!CMS_decrypt(cms, rkey, rcert, dcont, out, 0))
60        goto err;
61
62    ret = 0;
63
64 err:
65
66    if (ret) {
67        fprintf(stderr, "Error Decrypting Data\n");
68        ERR_print_errors_fp(stderr);
69    }
70
71    if (cms)
72        CMS_ContentInfo_free(cms);
73    if (rcert)
74        X509_free(rcert);
75    if (rkey)
76        EVP_PKEY_free(rkey);
77
78    if (in)
79        BIO_free(in);
80    if (out)
81        BIO_free(out);
82    if (tbio)
83        BIO_free(tbio);
84    if (dcont)
85        BIO_free(dcont);
86
87    return ret;
88
89}
90