1/*
2 * S/MIME detached data encrypt 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, *dout = NULL;
12    X509 *rcert = NULL;
13    STACK_OF(X509) *recips = NULL;
14    CMS_ContentInfo *cms = NULL;
15    int ret = 1;
16
17    int flags = CMS_STREAM | CMS_DETACHED;
18
19    OpenSSL_add_all_algorithms();
20    ERR_load_crypto_strings();
21
22    /* Read in recipient certificate */
23    tbio = BIO_new_file("signer.pem", "r");
24
25    if (!tbio)
26        goto err;
27
28    rcert = PEM_read_bio_X509(tbio, NULL, 0, NULL);
29
30    if (!rcert)
31        goto err;
32
33    /* Create recipient STACK and add recipient cert to it */
34    recips = sk_X509_new_null();
35
36    if (!recips || !sk_X509_push(recips, rcert))
37        goto err;
38
39    /*
40     * sk_X509_pop_free will free up recipient STACK and its contents so set
41     * rcert to NULL so it isn't freed up twice.
42     */
43    rcert = NULL;
44
45    /* Open content being encrypted */
46
47    in = BIO_new_file("encr.txt", "r");
48
49    dout = BIO_new_file("smencr.out", "wb");
50
51    if (!in)
52        goto err;
53
54    /* encrypt content */
55    cms = CMS_encrypt(recips, in, EVP_des_ede3_cbc(), flags);
56
57    if (!cms)
58        goto err;
59
60    out = BIO_new_file("smencr.pem", "w");
61    if (!out)
62        goto err;
63
64    if (!CMS_final(cms, in, dout, flags))
65        goto err;
66
67    /* Write out CMS structure without content */
68    if (!PEM_write_bio_CMS(out, cms))
69        goto err;
70
71    ret = 0;
72
73 err:
74
75    if (ret) {
76        fprintf(stderr, "Error Encrypting Data\n");
77        ERR_print_errors_fp(stderr);
78    }
79
80    if (cms)
81        CMS_ContentInfo_free(cms);
82    if (rcert)
83        X509_free(rcert);
84    if (recips)
85        sk_X509_pop_free(recips, X509_free);
86
87    if (in)
88        BIO_free(in);
89    if (out)
90        BIO_free(out);
91    if (dout)
92        BIO_free(dout);
93    if (tbio)
94        BIO_free(tbio);
95
96    return ret;
97
98}
99