1 /* Simple S/MIME signing example */ 2 #include <openssl/pem.h> 3 #include <openssl/cms.h> 4 #include <openssl/err.h> 5 6 int main(int argc, char **argv) 7 { 8 BIO *in = NULL, *out = NULL, *tbio = NULL; 9 X509 *scert = NULL; 10 EVP_PKEY *skey = NULL; 11 CMS_ContentInfo *cms = NULL; 12 int ret = 1; 13 14 /* For simple S/MIME signing use CMS_DETACHED. 15 * On OpenSSL 0.9.9 only: 16 * for streaming detached set CMS_DETACHED|CMS_STREAM 17 * for streaming non-detached set CMS_STREAM 18 */ 19 int flags = CMS_DETACHED|CMS_STREAM; 20 21 OpenSSL_add_all_algorithms(); 22 ERR_load_crypto_strings(); 23 24 /* Read in signer certificate and private key */ 25 tbio = BIO_new_file("signer.pem", "r"); 26 27 if (!tbio) 28 goto err; 29 30 scert = PEM_read_bio_X509(tbio, NULL, 0, NULL); 31 32 BIO_reset(tbio); 33 34 skey = PEM_read_bio_PrivateKey(tbio, NULL, 0, NULL); 35 36 if (!scert || !skey) 37 goto err; 38 39 /* Open content being signed */ 40 41 in = BIO_new_file("sign.txt", "r"); 42 43 if (!in) 44 goto err; 45 46 /* Sign content */ 47 cms = CMS_sign(scert, skey, NULL, in, flags); 48 49 if (!cms) 50 goto err; 51 52 out = BIO_new_file("smout.txt", "w"); 53 if (!out) 54 goto err; 55 56 if (!(flags & CMS_STREAM)) 57 BIO_reset(in); 58 59 /* Write out S/MIME message */ 60 if (!SMIME_write_CMS(out, cms, in, flags)) 61 goto err; 62 63 ret = 0; 64 65 err: 66 67 if (ret) 68 { 69 fprintf(stderr, "Error Signing Data\n"); 70 ERR_print_errors_fp(stderr); 71 } 72 73 if (cms) 74 CMS_ContentInfo_free(cms); 75 if (scert) 76 X509_free(scert); 77 if (skey) 78 EVP_PKEY_free(skey); 79 80 if (in) 81 BIO_free(in); 82 if (out) 83 BIO_free(out); 84 if (tbio) 85 BIO_free(tbio); 86 87 return ret; 88 89 } 90