1 /* Simple S/MIME verification example */ 2 #include <openssl/pem.h> 3 #include <openssl/pkcs7.h> 4 #include <openssl/err.h> 5 6 int main(int argc, char **argv) 7 { 8 BIO *in = NULL, *out = NULL, *tbio = NULL, *cont = NULL; 9 X509_STORE *st = NULL; 10 X509 *cacert = NULL; 11 PKCS7 *p7 = NULL; 12 13 int ret = 1; 14 15 OpenSSL_add_all_algorithms(); 16 ERR_load_crypto_strings(); 17 18 /* Set up trusted CA certificate store */ 19 20 st = X509_STORE_new(); 21 22 /* Read in signer certificate and private key */ 23 tbio = BIO_new_file("cacert.pem", "r"); 24 25 if (!tbio) 26 goto err; 27 28 cacert = PEM_read_bio_X509(tbio, NULL, 0, NULL); 29 30 if (!cacert) 31 goto err; 32 33 if (!X509_STORE_add_cert(st, cacert)) 34 goto err; 35 36 /* Open content being signed */ 37 38 in = BIO_new_file("smout.txt", "r"); 39 40 if (!in) 41 goto err; 42 43 /* Sign content */ 44 p7 = SMIME_read_PKCS7(in, &cont); 45 46 if (!p7) 47 goto err; 48 49 /* File to output verified content to */ 50 out = BIO_new_file("smver.txt", "w"); 51 if (!out) 52 goto err; 53 54 if (!PKCS7_verify(p7, NULL, st, cont, out, 0)) 55 { 56 fprintf(stderr, "Verification Failure\n"); 57 goto err; 58 } 59 60 fprintf(stderr, "Verification Successful\n"); 61 62 ret = 0; 63 64 err: 65 66 if (ret) 67 { 68 fprintf(stderr, "Error Verifying Data\n"); 69 ERR_print_errors_fp(stderr); 70 } 71 72 if (p7) 73 PKCS7_free(p7); 74 75 if (cacert) 76 X509_free(cacert); 77 78 if (in) 79 BIO_free(in); 80 if (out) 81 BIO_free(out); 82 if (tbio) 83 BIO_free(tbio); 84 85 return ret; 86 87 } 88