1 /* 2 * Copyright 2008-2023 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the Apache License 2.0 (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10 /* Simple S/MIME decryption example */ 11 #include <openssl/pem.h> 12 #include <openssl/cms.h> 13 #include <openssl/err.h> 14 15 int main(int argc, char **argv) 16 { 17 BIO *in = NULL, *out = NULL, *tbio = NULL; 18 X509 *rcert = NULL; 19 EVP_PKEY *rkey = NULL; 20 CMS_ContentInfo *cms = NULL; 21 int ret = EXIT_FAILURE; 22 23 OpenSSL_add_all_algorithms(); 24 ERR_load_crypto_strings(); 25 26 /* Read in recipient certificate and private key */ 27 tbio = BIO_new_file("signer.pem", "r"); 28 29 if (!tbio) 30 goto err; 31 32 rcert = PEM_read_bio_X509(tbio, NULL, 0, NULL); 33 34 if (BIO_reset(tbio) < 0) 35 goto err; 36 37 rkey = PEM_read_bio_PrivateKey(tbio, NULL, 0, NULL); 38 39 if (!rcert || !rkey) 40 goto err; 41 42 /* Open S/MIME message to decrypt */ 43 44 in = BIO_new_file("smencr.txt", "r"); 45 46 if (!in) 47 goto err; 48 49 /* Parse message */ 50 cms = SMIME_read_CMS(in, NULL); 51 52 if (!cms) 53 goto err; 54 55 out = BIO_new_file("decout.txt", "w"); 56 if (!out) 57 goto err; 58 59 /* Decrypt S/MIME message */ 60 if (!CMS_decrypt(cms, rkey, rcert, NULL, out, 0)) 61 goto err; 62 63 printf("Decryption Successful\n"); 64 65 ret = EXIT_SUCCESS; 66 67 err: 68 if (ret != EXIT_SUCCESS) { 69 fprintf(stderr, "Error Decrypting Data\n"); 70 ERR_print_errors_fp(stderr); 71 } 72 73 CMS_ContentInfo_free(cms); 74 X509_free(rcert); 75 EVP_PKEY_free(rkey); 76 BIO_free(in); 77 BIO_free(out); 78 BIO_free(tbio); 79 return ret; 80 } 81