1 /* dtls -- a very basic DTLS implementation 2 * 3 * Copyright (C) 2011--2012 Olaf Bergmann <bergmann@tzi.org> 4 * 5 * Permission is hereby granted, free of charge, to any person 6 * obtaining a copy of this software and associated documentation 7 * files (the "Software"), to deal in the Software without 8 * restriction, including without limitation the rights to use, copy, 9 * modify, merge, publish, distribute, sublicense, and/or sell copies 10 * of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be 14 * included in all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 17 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 18 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 19 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 20 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 21 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 22 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 23 * SOFTWARE. 24 */ 25 26 #ifndef _DTLS_CCM_H_ 27 #define _DTLS_CCM_H_ 28 29 #include "aes/rijndael.h" 30 31 /* implementation of Counter Mode CBC-MAC, RFC 3610 */ 32 33 #define DTLS_CCM_BLOCKSIZE 16 /**< size of hmac blocks */ 34 #define DTLS_CCM_MAX 16 /**< max number of bytes in digest */ 35 #define DTLS_CCM_NONCE_SIZE 12 /**< size of nonce */ 36 37 /** 38 * Authenticates and encrypts a message using AES in CCM mode. Please 39 * see also RFC 3610 for the meaning of \p M, \p L, \p lm and \p la. 40 * 41 * \param ctx The initialized rijndael_ctx object to be used for AES operations. 42 * \param M The number of authentication octets. 43 * \param L The number of bytes used to encode the message length. 44 * \param N The nonce value to use. You must provide \c DTLS_CCM_BLOCKSIZE 45 * nonce octets, although only the first \c 16 - \p L are used. 46 * \param msg The message to encrypt. The first \p la octets are additional 47 * authentication data that will be cleartext. Note that the 48 * encryption operation modifies the contents of \p msg and adds 49 * \p M bytes MAC. Therefore, the buffer must be at least 50 * \p lm + \p M bytes large. 51 * \param lm The actual length of \p msg. 52 * \param aad A pointer to the additional authentication data (can be \c NULL if 53 * \p la is zero). 54 * \param la The number of additional authentication octets (may be zero). 55 * \return FIXME 56 */ 57 long int 58 dtls_ccm_encrypt_message(rijndael_ctx *ctx, size_t M, size_t L, 59 unsigned char nonce[DTLS_CCM_BLOCKSIZE], 60 unsigned char *msg, size_t lm, 61 const unsigned char *aad, size_t la); 62 63 long int 64 dtls_ccm_decrypt_message(rijndael_ctx *ctx, size_t M, size_t L, 65 unsigned char nonce[DTLS_CCM_BLOCKSIZE], 66 unsigned char *msg, size_t lm, 67 const unsigned char *aad, size_t la); 68 69 #endif /* _DTLS_CCM_H_ */ 70
