1 /* 2 * Copyright 2013-2024 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 /* 11 * Simple AES CCM authenticated encryption with additional data (AEAD) 12 * demonstration program. 13 */ 14 15 #include <stdio.h> 16 #include <openssl/err.h> 17 #include <openssl/bio.h> 18 #include <openssl/evp.h> 19 #include <openssl/core_names.h> 20 21 /* AES-CCM test data obtained from NIST public test vectors */ 22 23 /* AES key */ 24 static const unsigned char ccm_key[] = { 25 0xce, 0xb0, 0x09, 0xae, 0xa4, 0x45, 0x44, 0x51, 0xfe, 0xad, 0xf0, 0xe6, 26 0xb3, 0x6f, 0x45, 0x55, 0x5d, 0xd0, 0x47, 0x23, 0xba, 0xa4, 0x48, 0xe8 27 }; 28 29 /* Unique nonce to be used for this message */ 30 static const unsigned char ccm_nonce[] = { 31 0x76, 0x40, 0x43, 0xc4, 0x94, 0x60, 0xb7 32 }; 33 34 /* 35 * Example of Additional Authenticated Data (AAD), i.e. unencrypted data 36 * which can be authenticated using the generated Tag value. 37 */ 38 static const unsigned char ccm_adata[] = { 39 0x6e, 0x80, 0xdd, 0x7f, 0x1b, 0xad, 0xf3, 0xa1, 0xc9, 0xab, 0x25, 0xc7, 40 0x5f, 0x10, 0xbd, 0xe7, 0x8c, 0x23, 0xfa, 0x0e, 0xb8, 0xf9, 0xaa, 0xa5, 41 0x3a, 0xde, 0xfb, 0xf4, 0xcb, 0xf7, 0x8f, 0xe4 42 }; 43 44 /* Example plaintext to encrypt */ 45 static const unsigned char ccm_pt[] = { 46 0xc8, 0xd2, 0x75, 0xf9, 0x19, 0xe1, 0x7d, 0x7f, 0xe6, 0x9c, 0x2a, 0x1f, 47 0x58, 0x93, 0x9d, 0xfe, 0x4d, 0x40, 0x37, 0x91, 0xb5, 0xdf, 0x13, 0x10 48 }; 49 50 /* Expected ciphertext value */ 51 static const unsigned char ccm_ct[] = { 52 0x8a, 0x0f, 0x3d, 0x82, 0x29, 0xe4, 0x8e, 0x74, 0x87, 0xfd, 0x95, 0xa2, 53 0x8a, 0xd3, 0x92, 0xc8, 0x0b, 0x36, 0x81, 0xd4, 0xfb, 0xc7, 0xbb, 0xfd 54 }; 55 56 /* Expected AEAD Tag value */ 57 static const unsigned char ccm_tag[] = { 58 0x2d, 0xd6, 0xef, 0x1c, 0x45, 0xd4, 0xcc, 0xb7, 0x23, 0xdc, 0x07, 0x44, 59 0x14, 0xdb, 0x50, 0x6d 60 }; 61 62 /* 63 * A library context and property query can be used to select & filter 64 * algorithm implementations. If they are NULL then the default library 65 * context and properties are used. 66 */ 67 static OSSL_LIB_CTX *libctx = NULL; 68 static const char *propq = NULL; 69 70 static int aes_ccm_encrypt(void) 71 { 72 int ret = 0; 73 EVP_CIPHER_CTX *ctx; 74 EVP_CIPHER *cipher = NULL; 75 int outlen, tmplen; 76 size_t ccm_nonce_len = sizeof(ccm_nonce); 77 size_t ccm_tag_len = sizeof(ccm_tag); 78 unsigned char outbuf[1024]; 79 unsigned char outtag[16]; 80 OSSL_PARAM params[3] = { 81 OSSL_PARAM_END, OSSL_PARAM_END, OSSL_PARAM_END 82 }; 83 84 printf("AES CCM Encrypt:\n"); 85 printf("Plaintext:\n"); 86 BIO_dump_fp(stdout, ccm_pt, sizeof(ccm_pt)); 87 88 /* Create a context for the encrypt operation */ 89 if ((ctx = EVP_CIPHER_CTX_new()) == NULL) 90 goto err; 91 92 /* Fetch the cipher implementation */ 93 if ((cipher = EVP_CIPHER_fetch(libctx, "AES-192-CCM", propq)) == NULL) 94 goto err; 95 96 /* Default nonce length for AES-CCM is 7 bytes (56 bits). */ 97 params[0] = OSSL_PARAM_construct_size_t(OSSL_CIPHER_PARAM_AEAD_IVLEN, 98 &ccm_nonce_len); 99 /* Set tag length */ 100 params[1] = OSSL_PARAM_construct_octet_string(OSSL_CIPHER_PARAM_AEAD_TAG, 101 NULL, ccm_tag_len); 102 103 /* 104 * Initialise encrypt operation with the cipher & mode, 105 * nonce length and tag length parameters. 106 */ 107 if (!EVP_EncryptInit_ex2(ctx, cipher, NULL, NULL, params)) 108 goto err; 109 110 /* Initialise key and nonce */ 111 if (!EVP_EncryptInit_ex(ctx, NULL, NULL, ccm_key, ccm_nonce)) 112 goto err; 113 114 /* Set plaintext length: only needed if AAD is used */ 115 if (!EVP_EncryptUpdate(ctx, NULL, &outlen, NULL, sizeof(ccm_pt))) 116 goto err; 117 118 /* Zero or one call to specify any AAD */ 119 if (!EVP_EncryptUpdate(ctx, NULL, &outlen, ccm_adata, sizeof(ccm_adata))) 120 goto err; 121 122 /* Encrypt plaintext: can only be called once */ 123 if (!EVP_EncryptUpdate(ctx, outbuf, &outlen, ccm_pt, sizeof(ccm_pt))) 124 goto err; 125 126 /* Output encrypted block */ 127 printf("Ciphertext:\n"); 128 BIO_dump_fp(stdout, outbuf, outlen); 129 130 /* Finalise: note get no output for CCM */ 131 if (!EVP_EncryptFinal_ex(ctx, NULL, &tmplen)) 132 goto err; 133 134 /* Get tag */ 135 params[0] = OSSL_PARAM_construct_octet_string(OSSL_CIPHER_PARAM_AEAD_TAG, 136 outtag, ccm_tag_len); 137 params[1] = OSSL_PARAM_construct_end(); 138 139 if (!EVP_CIPHER_CTX_get_params(ctx, params)) 140 goto err; 141 142 /* Output tag */ 143 printf("Tag:\n"); 144 BIO_dump_fp(stdout, outtag, ccm_tag_len); 145 146 ret = 1; 147 err: 148 if (!ret) 149 ERR_print_errors_fp(stderr); 150 151 EVP_CIPHER_free(cipher); 152 EVP_CIPHER_CTX_free(ctx); 153 154 return ret; 155 } 156 157 static int aes_ccm_decrypt(void) 158 { 159 int ret = 0; 160 EVP_CIPHER_CTX *ctx; 161 EVP_CIPHER *cipher = NULL; 162 int outlen, rv; 163 unsigned char outbuf[1024]; 164 size_t ccm_nonce_len = sizeof(ccm_nonce); 165 OSSL_PARAM params[3] = { 166 OSSL_PARAM_END, OSSL_PARAM_END, OSSL_PARAM_END 167 }; 168 169 printf("AES CCM Decrypt:\n"); 170 printf("Ciphertext:\n"); 171 BIO_dump_fp(stdout, ccm_ct, sizeof(ccm_ct)); 172 173 if ((ctx = EVP_CIPHER_CTX_new()) == NULL) 174 goto err; 175 176 /* Fetch the cipher implementation */ 177 if ((cipher = EVP_CIPHER_fetch(libctx, "AES-192-CCM", propq)) == NULL) 178 goto err; 179 180 /* Set nonce length if default 96 bits is not appropriate */ 181 params[0] = OSSL_PARAM_construct_size_t(OSSL_CIPHER_PARAM_AEAD_IVLEN, 182 &ccm_nonce_len); 183 /* Set tag length */ 184 params[1] = OSSL_PARAM_construct_octet_string(OSSL_CIPHER_PARAM_AEAD_TAG, 185 (unsigned char *)ccm_tag, 186 sizeof(ccm_tag)); 187 /* 188 * Initialise decrypt operation with the cipher & mode, 189 * nonce length and expected tag parameters. 190 */ 191 if (!EVP_DecryptInit_ex2(ctx, cipher, NULL, NULL, params)) 192 goto err; 193 194 /* Specify key and IV */ 195 if (!EVP_DecryptInit_ex(ctx, NULL, NULL, ccm_key, ccm_nonce)) 196 goto err; 197 198 /* Set ciphertext length: only needed if we have AAD */ 199 if (!EVP_DecryptUpdate(ctx, NULL, &outlen, NULL, sizeof(ccm_ct))) 200 goto err; 201 202 /* Zero or one call to specify any AAD */ 203 if (!EVP_DecryptUpdate(ctx, NULL, &outlen, ccm_adata, sizeof(ccm_adata))) 204 goto err; 205 206 /* Decrypt plaintext, verify tag: can only be called once */ 207 rv = EVP_DecryptUpdate(ctx, outbuf, &outlen, ccm_ct, sizeof(ccm_ct)); 208 209 /* Output decrypted block: if tag verify failed we get nothing */ 210 if (rv > 0) { 211 printf("Tag verify successful!\nPlaintext:\n"); 212 BIO_dump_fp(stdout, outbuf, outlen); 213 } else { 214 printf("Tag verify failed!\nPlaintext not available\n"); 215 goto err; 216 } 217 ret = 1; 218 err: 219 if (!ret) 220 ERR_print_errors_fp(stderr); 221 222 EVP_CIPHER_free(cipher); 223 EVP_CIPHER_CTX_free(ctx); 224 225 return ret; 226 } 227 228 int main(int argc, char **argv) 229 { 230 if (!aes_ccm_encrypt()) 231 return EXIT_FAILURE; 232 233 if (!aes_ccm_decrypt()) 234 return EXIT_FAILURE; 235 236 return EXIT_SUCCESS; 237 } 238
Indexes created Sun Mar 01 05:31:48 UTC 2026