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/*
* cipher.h
*
* common interface to ciphers
*
* David A. McGrew
* Cisco Systems, Inc.
*/
/*
*
* Copyright (c) 2001-2006, Cisco Systems, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* Neither the name of the Cisco Systems, Inc. nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#ifndef CIPHER_H
#define CIPHER_H
#include "datatypes.h"
#include "rdbx.h" /* for xtd_seq_num_t */
#include "err.h" /* for error codes */
/**
* @brief cipher_direction_t defines a particular cipher operation.
*
* A cipher_direction_t is an enum that describes a particular cipher
* operation, i.e. encryption or decryption. For some ciphers, this
* distinction does not matter, but for others, it is essential.
*/
typedef enum {
direction_encrypt, /**< encryption (convert plaintext to ciphertext) */
direction_decrypt, /**< decryption (convert ciphertext to plaintext) */
direction_any /**< encryption or decryption */
} cipher_direction_t;
/*
* the cipher_pointer and cipher_type_pointer definitions are needed
* as cipher_t and cipher_type_t are not yet defined
*/
typedef struct cipher_type_t *cipher_type_pointer_t;
typedef struct cipher_t *cipher_pointer_t;
/*
* a cipher_alloc_func_t allocates (but does not initialize) a cipher_t
*/
typedef err_status_t (*cipher_alloc_func_t)
(cipher_pointer_t *cp, int key_len);
/*
* a cipher_init_func_t [re-]initializes a cipher_t with a given key
* and direction (i.e., encrypt or decrypt)
*/
typedef err_status_t (*cipher_init_func_t)
(void *state, const uint8_t *key, cipher_direction_t dir);
/* a cipher_dealloc_func_t de-allocates a cipher_t */
typedef err_status_t (*cipher_dealloc_func_t)(cipher_pointer_t cp);
/* a cipher_set_segment_func_t sets the segment index of a cipher_t */
typedef err_status_t (*cipher_set_segment_func_t)
(void *state, xtd_seq_num_t idx);
/* a cipher_encrypt_func_t encrypts data in-place */
typedef err_status_t (*cipher_encrypt_func_t)
(void *state, uint8_t *buffer, unsigned int *octets_to_encrypt);
/* a cipher_decrypt_func_t decrypts data in-place */
typedef err_status_t (*cipher_decrypt_func_t)
(void *state, uint8_t *buffer, unsigned int *octets_to_decrypt);
/*
* a cipher_set_nonce_seq_func_t function sets both the nonce
* and the extended sequence number
*/
typedef err_status_t (*cipher_set_iv_func_t)
(cipher_pointer_t cp, void *iv);
/*
* cipher_test_case_t is a (list of) key, salt, xtd_seq_num_t,
* plaintext, and ciphertext values that are known to be correct for a
* particular cipher. this data can be used to test an implementation
* in an on-the-fly self test of the correcness of the implementation.
* (see the cipher_type_self_test() function below)
*/
typedef struct cipher_test_case_t {
int key_length_octets; /* octets in key */
uint8_t *key; /* key */
uint8_t *idx; /* packet index */
int plaintext_length_octets; /* octets in plaintext */
uint8_t *plaintext; /* plaintext */
int ciphertext_length_octets; /* octets in plaintext */
uint8_t *ciphertext; /* ciphertext */
struct cipher_test_case_t *next_test_case; /* pointer to next testcase */
} cipher_test_case_t;
/* cipher_type_t defines the 'metadata' for a particular cipher type */
typedef struct cipher_type_t {
cipher_alloc_func_t alloc;
cipher_dealloc_func_t dealloc;
cipher_init_func_t init;
cipher_encrypt_func_t encrypt;
cipher_encrypt_func_t decrypt;
cipher_set_iv_func_t set_iv;
char *description;
int ref_count;
cipher_test_case_t *test_data;
debug_module_t *debug;
} cipher_type_t;
/*
* cipher_t defines an instantiation of a particular cipher, with fixed
* key length, key and salt values
*/
typedef struct cipher_t {
cipher_type_t *type;
void *state;
int key_len;
#ifdef FORCE_64BIT_ALIGN
int pad;
#endif
} cipher_t;
/* some syntactic sugar on these function types */
#define cipher_type_alloc(ct, c, klen) ((ct)->alloc((c), (klen)))
#define cipher_dealloc(c) (((c)->type)->dealloc(c))
#define cipher_init(c, k, dir) (((c)->type)->init(((c)->state), (k), (dir)))
#define cipher_encrypt(c, buf, len) \
(((c)->type)->encrypt(((c)->state), (buf), (len)))
#define cipher_decrypt(c, buf, len) \
(((c)->type)->decrypt(((c)->state), (buf), (len)))
#define cipher_set_iv(c, n) \
((c) ? (((c)->type)->set_iv(((cipher_pointer_t)(c)->state), (n))) : \
err_status_no_such_op)
err_status_t
cipher_output(cipher_t *c, uint8_t *buffer, int num_octets_to_output);
/* some bookkeeping functions */
int
cipher_get_key_length(const cipher_t *c);
/*
* cipher_type_self_test() tests a cipher against test cases provided in
* an array of values of key/xtd_seq_num_t/plaintext/ciphertext
* that is known to be good
*/
err_status_t
cipher_type_self_test(const cipher_type_t *ct);
/*
* cipher_bits_per_second(c, l, t) computes (and estimate of) the
* number of bits that a cipher implementation can encrypt in a second
*
* c is a cipher (which MUST be allocated and initialized already), l
* is the length in octets of the test data to be encrypted, and t is
* the number of trials
*
* if an error is encountered, then the value 0 is returned
*/
uint64_t
cipher_bits_per_second(cipher_t *c, int octets_in_buffer, int num_trials);
#endif /* CIPHER_H */
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