1 /*
2 * Copyright 2013-2021 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 OSSL_LIB_CTX *libctx = NULL;
68 const char *propq = NULL;
69
70
aes_ccm_encrypt(void)71 int aes_ccm_encrypt(void)
72 {
73 int ret = 0;
74 EVP_CIPHER_CTX *ctx;
75 EVP_CIPHER *cipher = NULL;
76 int outlen, tmplen;
77 size_t ccm_nonce_len = sizeof(ccm_nonce);
78 size_t ccm_tag_len = sizeof(ccm_tag);
79 unsigned char outbuf[1024];
80 unsigned char outtag[16];
81 OSSL_PARAM params[3] = {
82 OSSL_PARAM_END, OSSL_PARAM_END, OSSL_PARAM_END
83 };
84
85 printf("AES CCM Encrypt:\n");
86 printf("Plaintext:\n");
87 BIO_dump_fp(stdout, ccm_pt, sizeof(ccm_pt));
88
89 /* Create a context for the encrypt operation */
90 if ((ctx = EVP_CIPHER_CTX_new()) == NULL)
91 goto err;
92
93 /* Fetch the cipher implementation */
94 if ((cipher = EVP_CIPHER_fetch(libctx, "AES-192-CCM", propq)) == NULL)
95 goto err;
96
97 /* Set nonce length if default 96 bits is not appropriate */
98 params[0] = OSSL_PARAM_construct_size_t(OSSL_CIPHER_PARAM_AEAD_IVLEN,
99 &ccm_nonce_len);
100 /* Set tag length */
101 params[1] = OSSL_PARAM_construct_octet_string(OSSL_CIPHER_PARAM_AEAD_TAG,
102 NULL, ccm_tag_len);
103
104 /*
105 * Initialise encrypt operation with the cipher & mode,
106 * nonce length and tag length parameters.
107 */
108 if (!EVP_EncryptInit_ex2(ctx, cipher, NULL, NULL, params))
109 goto err;
110
111 /* Initialise key and nonce */
112 if (!EVP_EncryptInit_ex(ctx, NULL, NULL, ccm_key, ccm_nonce))
113 goto err;
114
115 /* Set plaintext length: only needed if AAD is used */
116 if (!EVP_EncryptUpdate(ctx, NULL, &outlen, NULL, sizeof(ccm_pt)))
117 goto err;
118
119 /* Zero or one call to specify any AAD */
120 if (!EVP_EncryptUpdate(ctx, NULL, &outlen, ccm_adata, sizeof(ccm_adata)))
121 goto err;
122
123 /* Encrypt plaintext: can only be called once */
124 if (!EVP_EncryptUpdate(ctx, outbuf, &outlen, ccm_pt, sizeof(ccm_pt)))
125 goto err;
126
127 /* Output encrypted block */
128 printf("Ciphertext:\n");
129 BIO_dump_fp(stdout, outbuf, outlen);
130
131 /* Finalise: note get no output for CCM */
132 if (!EVP_EncryptFinal_ex(ctx, NULL, &tmplen))
133 goto err;
134
135 /* Get tag */
136 params[0] = OSSL_PARAM_construct_octet_string(OSSL_CIPHER_PARAM_AEAD_TAG,
137 outtag, ccm_tag_len);
138 params[1] = OSSL_PARAM_construct_end();
139
140 if (!EVP_CIPHER_CTX_get_params(ctx, params))
141 goto err;
142
143 /* Output tag */
144 printf("Tag:\n");
145 BIO_dump_fp(stdout, outtag, ccm_tag_len);
146
147 ret = 1;
148 err:
149 if (!ret)
150 ERR_print_errors_fp(stderr);
151
152 EVP_CIPHER_free(cipher);
153 EVP_CIPHER_CTX_free(ctx);
154
155 return ret;
156 }
157
aes_ccm_decrypt(void)158 int aes_ccm_decrypt(void)
159 {
160 int ret = 0;
161 EVP_CIPHER_CTX *ctx;
162 EVP_CIPHER *cipher = NULL;
163 int outlen, rv;
164 unsigned char outbuf[1024];
165 size_t ccm_nonce_len = sizeof(ccm_nonce);
166 OSSL_PARAM params[3] = {
167 OSSL_PARAM_END, OSSL_PARAM_END, OSSL_PARAM_END
168 };
169
170 printf("AES CCM Decrypt:\n");
171 printf("Ciphertext:\n");
172 BIO_dump_fp(stdout, ccm_ct, sizeof(ccm_ct));
173
174 if ((ctx = EVP_CIPHER_CTX_new()) == NULL)
175 goto err;
176
177 /* Fetch the cipher implementation */
178 if ((cipher = EVP_CIPHER_fetch(libctx, "AES-192-CCM", propq)) == NULL)
179 goto err;
180
181 /* Set nonce length if default 96 bits is not appropriate */
182 params[0] = OSSL_PARAM_construct_size_t(OSSL_CIPHER_PARAM_AEAD_IVLEN,
183 &ccm_nonce_len);
184 /* Set tag length */
185 params[1] = OSSL_PARAM_construct_octet_string(OSSL_CIPHER_PARAM_AEAD_TAG,
186 (unsigned char *)ccm_tag,
187 sizeof(ccm_tag));
188 /*
189 * Initialise decrypt operation with the cipher & mode,
190 * nonce length and expected tag parameters.
191 */
192 if (!EVP_DecryptInit_ex2(ctx, cipher, NULL, NULL, params))
193 goto err;
194
195 /* Specify key and IV */
196 if (!EVP_DecryptInit_ex(ctx, NULL, NULL, ccm_key, ccm_nonce))
197 goto err;
198
199 /* Set ciphertext length: only needed if we have AAD */
200 if (!EVP_DecryptUpdate(ctx, NULL, &outlen, NULL, sizeof(ccm_ct)))
201 goto err;
202
203 /* Zero or one call to specify any AAD */
204 if (!EVP_DecryptUpdate(ctx, NULL, &outlen, ccm_adata, sizeof(ccm_adata)))
205 goto err;
206
207 /* Decrypt plaintext, verify tag: can only be called once */
208 rv = EVP_DecryptUpdate(ctx, outbuf, &outlen, ccm_ct, sizeof(ccm_ct));
209
210 /* Output decrypted block: if tag verify failed we get nothing */
211 if (rv > 0) {
212 printf("Tag verify successful!\nPlaintext:\n");
213 BIO_dump_fp(stdout, outbuf, outlen);
214 } else {
215 printf("Tag verify failed!\nPlaintext not available\n");
216 goto err;
217 }
218 ret = 1;
219 err:
220 if (!ret)
221 ERR_print_errors_fp(stderr);
222
223 EVP_CIPHER_free(cipher);
224 EVP_CIPHER_CTX_free(ctx);
225
226 return ret;
227 }
228
main(int argc,char ** argv)229 int main(int argc, char **argv)
230 {
231 if (!aes_ccm_encrypt())
232 return 1;
233
234 if (!aes_ccm_decrypt())
235 return 1;
236
237 return 0;
238 }
239