1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
/*
* Copyright 2013-2023 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
/*
* Simple AES CCM authenticated encryption with additional data (AEAD)
* demonstration program.
*/
#include <stdio.h>
#include <openssl/err.h>
#include <openssl/bio.h>
#include <openssl/evp.h>
#include <openssl/core_names.h>
/* AES-CCM test data obtained from NIST public test vectors */
/* AES key */
static const unsigned char ccm_key[] = {
0xce, 0xb0, 0x09, 0xae, 0xa4, 0x45, 0x44, 0x51, 0xfe, 0xad, 0xf0, 0xe6,
0xb3, 0x6f, 0x45, 0x55, 0x5d, 0xd0, 0x47, 0x23, 0xba, 0xa4, 0x48, 0xe8
};
/* Unique nonce to be used for this message */
static const unsigned char ccm_nonce[] = {
0x76, 0x40, 0x43, 0xc4, 0x94, 0x60, 0xb7
};
/*
* Example of Additional Authenticated Data (AAD), i.e. unencrypted data
* which can be authenticated using the generated Tag value.
*/
static const unsigned char ccm_adata[] = {
0x6e, 0x80, 0xdd, 0x7f, 0x1b, 0xad, 0xf3, 0xa1, 0xc9, 0xab, 0x25, 0xc7,
0x5f, 0x10, 0xbd, 0xe7, 0x8c, 0x23, 0xfa, 0x0e, 0xb8, 0xf9, 0xaa, 0xa5,
0x3a, 0xde, 0xfb, 0xf4, 0xcb, 0xf7, 0x8f, 0xe4
};
/* Example plaintext to encrypt */
static const unsigned char ccm_pt[] = {
0xc8, 0xd2, 0x75, 0xf9, 0x19, 0xe1, 0x7d, 0x7f, 0xe6, 0x9c, 0x2a, 0x1f,
0x58, 0x93, 0x9d, 0xfe, 0x4d, 0x40, 0x37, 0x91, 0xb5, 0xdf, 0x13, 0x10
};
/* Expected ciphertext value */
static const unsigned char ccm_ct[] = {
0x8a, 0x0f, 0x3d, 0x82, 0x29, 0xe4, 0x8e, 0x74, 0x87, 0xfd, 0x95, 0xa2,
0x8a, 0xd3, 0x92, 0xc8, 0x0b, 0x36, 0x81, 0xd4, 0xfb, 0xc7, 0xbb, 0xfd
};
/* Expected AEAD Tag value */
static const unsigned char ccm_tag[] = {
0x2d, 0xd6, 0xef, 0x1c, 0x45, 0xd4, 0xcc, 0xb7, 0x23, 0xdc, 0x07, 0x44,
0x14, 0xdb, 0x50, 0x6d
};
/*
* A library context and property query can be used to select & filter
* algorithm implementations. If they are NULL then the default library
* context and properties are used.
*/
static OSSL_LIB_CTX *libctx = NULL;
static const char *propq = NULL;
static int aes_ccm_encrypt(void)
{
int ret = 0;
EVP_CIPHER_CTX *ctx;
EVP_CIPHER *cipher = NULL;
int outlen, tmplen;
size_t ccm_nonce_len = sizeof(ccm_nonce);
size_t ccm_tag_len = sizeof(ccm_tag);
unsigned char outbuf[1024];
unsigned char outtag[16];
OSSL_PARAM params[3] = {
OSSL_PARAM_END, OSSL_PARAM_END, OSSL_PARAM_END
};
printf("AES CCM Encrypt:\n");
printf("Plaintext:\n");
BIO_dump_fp(stdout, ccm_pt, sizeof(ccm_pt));
/* Create a context for the encrypt operation */
if ((ctx = EVP_CIPHER_CTX_new()) == NULL)
goto err;
/* Fetch the cipher implementation */
if ((cipher = EVP_CIPHER_fetch(libctx, "AES-192-CCM", propq)) == NULL)
goto err;
/* Set nonce length if default 96 bits is not appropriate */
params[0] = OSSL_PARAM_construct_size_t(OSSL_CIPHER_PARAM_AEAD_IVLEN,
&ccm_nonce_len);
/* Set tag length */
params[1] = OSSL_PARAM_construct_octet_string(OSSL_CIPHER_PARAM_AEAD_TAG,
NULL, ccm_tag_len);
/*
* Initialise encrypt operation with the cipher & mode,
* nonce length and tag length parameters.
*/
if (!EVP_EncryptInit_ex2(ctx, cipher, NULL, NULL, params))
goto err;
/* Initialise key and nonce */
if (!EVP_EncryptInit_ex(ctx, NULL, NULL, ccm_key, ccm_nonce))
goto err;
/* Set plaintext length: only needed if AAD is used */
if (!EVP_EncryptUpdate(ctx, NULL, &outlen, NULL, sizeof(ccm_pt)))
goto err;
/* Zero or one call to specify any AAD */
if (!EVP_EncryptUpdate(ctx, NULL, &outlen, ccm_adata, sizeof(ccm_adata)))
goto err;
/* Encrypt plaintext: can only be called once */
if (!EVP_EncryptUpdate(ctx, outbuf, &outlen, ccm_pt, sizeof(ccm_pt)))
goto err;
/* Output encrypted block */
printf("Ciphertext:\n");
BIO_dump_fp(stdout, outbuf, outlen);
/* Finalise: note get no output for CCM */
if (!EVP_EncryptFinal_ex(ctx, NULL, &tmplen))
goto err;
/* Get tag */
params[0] = OSSL_PARAM_construct_octet_string(OSSL_CIPHER_PARAM_AEAD_TAG,
outtag, ccm_tag_len);
params[1] = OSSL_PARAM_construct_end();
if (!EVP_CIPHER_CTX_get_params(ctx, params))
goto err;
/* Output tag */
printf("Tag:\n");
BIO_dump_fp(stdout, outtag, ccm_tag_len);
ret = 1;
err:
if (!ret)
ERR_print_errors_fp(stderr);
EVP_CIPHER_free(cipher);
EVP_CIPHER_CTX_free(ctx);
return ret;
}
static int aes_ccm_decrypt(void)
{
int ret = 0;
EVP_CIPHER_CTX *ctx;
EVP_CIPHER *cipher = NULL;
int outlen, rv;
unsigned char outbuf[1024];
size_t ccm_nonce_len = sizeof(ccm_nonce);
OSSL_PARAM params[3] = {
OSSL_PARAM_END, OSSL_PARAM_END, OSSL_PARAM_END
};
printf("AES CCM Decrypt:\n");
printf("Ciphertext:\n");
BIO_dump_fp(stdout, ccm_ct, sizeof(ccm_ct));
if ((ctx = EVP_CIPHER_CTX_new()) == NULL)
goto err;
/* Fetch the cipher implementation */
if ((cipher = EVP_CIPHER_fetch(libctx, "AES-192-CCM", propq)) == NULL)
goto err;
/* Set nonce length if default 96 bits is not appropriate */
params[0] = OSSL_PARAM_construct_size_t(OSSL_CIPHER_PARAM_AEAD_IVLEN,
&ccm_nonce_len);
/* Set tag length */
params[1] = OSSL_PARAM_construct_octet_string(OSSL_CIPHER_PARAM_AEAD_TAG,
(unsigned char *)ccm_tag,
sizeof(ccm_tag));
/*
* Initialise decrypt operation with the cipher & mode,
* nonce length and expected tag parameters.
*/
if (!EVP_DecryptInit_ex2(ctx, cipher, NULL, NULL, params))
goto err;
/* Specify key and IV */
if (!EVP_DecryptInit_ex(ctx, NULL, NULL, ccm_key, ccm_nonce))
goto err;
/* Set ciphertext length: only needed if we have AAD */
if (!EVP_DecryptUpdate(ctx, NULL, &outlen, NULL, sizeof(ccm_ct)))
goto err;
/* Zero or one call to specify any AAD */
if (!EVP_DecryptUpdate(ctx, NULL, &outlen, ccm_adata, sizeof(ccm_adata)))
goto err;
/* Decrypt plaintext, verify tag: can only be called once */
rv = EVP_DecryptUpdate(ctx, outbuf, &outlen, ccm_ct, sizeof(ccm_ct));
/* Output decrypted block: if tag verify failed we get nothing */
if (rv > 0) {
printf("Tag verify successful!\nPlaintext:\n");
BIO_dump_fp(stdout, outbuf, outlen);
} else {
printf("Tag verify failed!\nPlaintext not available\n");
goto err;
}
ret = 1;
err:
if (!ret)
ERR_print_errors_fp(stderr);
EVP_CIPHER_free(cipher);
EVP_CIPHER_CTX_free(ctx);
return ret;
}
int main(int argc, char **argv)
{
if (!aes_ccm_encrypt())
return EXIT_FAILURE;
if (!aes_ccm_decrypt())
return EXIT_FAILURE;
return EXIT_SUCCESS;
}
|
