1 /* S/MIME detached data encrypt example: rarely done but
2  * should the need arise this is an example....
3  */
4 #include <openssl/pem.h>
5 #include <openssl/cms.h>
6 #include <openssl/err.h>
7 
8 int main(int argc, char **argv)
9 	{
10 	BIO *in = NULL, *out = NULL, *tbio = NULL, *dout = NULL;
11 	X509 *rcert = NULL;
12 	STACK_OF(X509) *recips = NULL;
13 	CMS_ContentInfo *cms = NULL;
14 	int ret = 1;
15 
16 	int flags = CMS_STREAM|CMS_DETACHED;
17 
18 	OpenSSL_add_all_algorithms();
19 	ERR_load_crypto_strings();
20 
21 	/* Read in recipient certificate */
22 	tbio = BIO_new_file("signer.pem", "r");
23 
24 	if (!tbio)
25 		goto err;
26 
27 	rcert = PEM_read_bio_X509(tbio, NULL, 0, NULL);
28 
29 	if (!rcert)
30 		goto err;
31 
32 	/* Create recipient STACK and add recipient cert to it */
33 	recips = sk_X509_new_null();
34 
35 	if (!recips || !sk_X509_push(recips, rcert))
36 		goto err;
37 
38 	/* sk_X509_pop_free will free up recipient STACK and its contents
39 	 * so set rcert to NULL so it isn't freed up twice.
40 	 */
41 	rcert = NULL;
42 
43 	/* Open content being encrypted */
44 
45 	in = BIO_new_file("encr.txt", "r");
46 
47 	dout = BIO_new_file("smencr.out", "wb");
48 
49 	if (!in)
50 		goto err;
51 
52 	/* encrypt content */
53 	cms = CMS_encrypt(recips, in, EVP_des_ede3_cbc(), flags);
54 
55 	if (!cms)
56 		goto err;
57 
58 	out = BIO_new_file("smencr.pem", "w");
59 	if (!out)
60 		goto err;
61 
62 	if (!CMS_final(cms, in, dout, flags))
63 		goto err;
64 
65 	/* Write out CMS structure without content */
66 	if (!PEM_write_bio_CMS(out, cms))
67 		goto err;
68 
69 	ret = 0;
70 
71 	err:
72 
73 	if (ret)
74 		{
75 		fprintf(stderr, "Error Encrypting Data\n");
76 		ERR_print_errors_fp(stderr);
77 		}
78 
79 	if (cms)
80 		CMS_ContentInfo_free(cms);
81 	if (rcert)
82 		X509_free(rcert);
83 	if (recips)
84 		sk_X509_pop_free(recips, X509_free);
85 
86 	if (in)
87 		BIO_free(in);
88 	if (out)
89 		BIO_free(out);
90 	if (dout)
91 		BIO_free(dout);
92 	if (tbio)
93 		BIO_free(tbio);
94 
95 	return ret;
96 
97 	}
98