1/*
2 * cipher.h
3 *
4 * common interface to ciphers
5 *
6 * David A. McGrew
7 * Cisco Systems, Inc.
8 */
9/*
10 *
11 * Copyright (c) 2001-2006, Cisco Systems, Inc.
12 * All rights reserved.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 *
18 *   Redistributions of source code must retain the above copyright
19 *   notice, this list of conditions and the following disclaimer.
20 *
21 *   Redistributions in binary form must reproduce the above
22 *   copyright notice, this list of conditions and the following
23 *   disclaimer in the documentation and/or other materials provided
24 *   with the distribution.
25 *
26 *   Neither the name of the Cisco Systems, Inc. nor the names of its
27 *   contributors may be used to endorse or promote products derived
28 *   from this software without specific prior written permission.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
31 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
32 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
33 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
34 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
35 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
36 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
37 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
41 * OF THE POSSIBILITY OF SUCH DAMAGE.
42 *
43 */
44
45
46#ifndef CIPHER_H
47#define CIPHER_H
48
49#include "datatypes.h"
50#include "rdbx.h"               /* for xtd_seq_num_t */
51#include "err.h"                /* for error codes  */
52#include "crypto.h"		/* for cipher_type_id_t */
53#include "crypto_types.h"	/* for values of cipher_type_id_t */
54
55
56/**
57 * @brief cipher_direction_t defines a particular cipher operation.
58 *
59 * A cipher_direction_t is an enum that describes a particular cipher
60 * operation, i.e. encryption or decryption.  For some ciphers, this
61 * distinction does not matter, but for others, it is essential.
62 */
63
64typedef enum {
65  direction_encrypt, /**< encryption (convert plaintext to ciphertext) */
66  direction_decrypt, /**< decryption (convert ciphertext to plaintext) */
67  direction_any      /**< encryption or decryption                     */
68} cipher_direction_t;
69
70/*
71 * the cipher_pointer and cipher_type_pointer definitions are needed
72 * as cipher_t and cipher_type_t are not yet defined
73 */
74
75typedef struct cipher_type_t *cipher_type_pointer_t;
76typedef struct cipher_t      *cipher_pointer_t;
77
78/*
79 *  a cipher_alloc_func_t allocates (but does not initialize) a cipher_t
80 */
81
82typedef err_status_t (*cipher_alloc_func_t)
83     (cipher_pointer_t *cp, int key_len);
84
85/*
86 * a cipher_init_func_t [re-]initializes a cipher_t with a given key
87 * and direction (i.e., encrypt or decrypt)
88 */
89
90typedef err_status_t (*cipher_init_func_t)
91(void *state, const uint8_t *key, int key_len, cipher_direction_t dir);
92
93/* a cipher_dealloc_func_t de-allocates a cipher_t */
94
95typedef err_status_t (*cipher_dealloc_func_t)(cipher_pointer_t cp);
96
97/* a cipher_set_segment_func_t sets the segment index of a cipher_t */
98
99typedef err_status_t (*cipher_set_segment_func_t)
100     (void *state, xtd_seq_num_t idx);
101
102/* a cipher_encrypt_func_t encrypts data in-place */
103
104typedef err_status_t (*cipher_encrypt_func_t)
105     (void *state, uint8_t *buffer, unsigned int *octets_to_encrypt);
106
107/* a cipher_decrypt_func_t decrypts data in-place */
108
109typedef err_status_t (*cipher_decrypt_func_t)
110     (void *state, uint8_t *buffer, unsigned int *octets_to_decrypt);
111
112/*
113 * a cipher_set_iv_func_t function sets the current initialization vector
114 */
115
116typedef err_status_t (*cipher_set_iv_func_t)
117     (cipher_pointer_t cp, void *iv);
118
119/*
120 * cipher_test_case_t is a (list of) key, salt, xtd_seq_num_t,
121 * plaintext, and ciphertext values that are known to be correct for a
122 * particular cipher.  this data can be used to test an implementation
123 * in an on-the-fly self test of the correcness of the implementation.
124 * (see the cipher_type_self_test() function below)
125 */
126
127typedef struct cipher_test_case_t {
128  int key_length_octets;                      /* octets in key            */
129  uint8_t *key;                               /* key                      */
130  uint8_t *idx;                               /* packet index             */
131  int plaintext_length_octets;                /* octets in plaintext      */
132  uint8_t *plaintext;                         /* plaintext                */
133  int ciphertext_length_octets;               /* octets in plaintext      */
134  uint8_t *ciphertext;                        /* ciphertext               */
135  struct cipher_test_case_t *next_test_case;  /* pointer to next testcase */
136} cipher_test_case_t;
137
138/* cipher_type_t defines the 'metadata' for a particular cipher type */
139
140typedef struct cipher_type_t {
141  cipher_alloc_func_t         alloc;
142  cipher_dealloc_func_t       dealloc;
143  cipher_init_func_t          init;
144  cipher_encrypt_func_t       encrypt;
145  cipher_encrypt_func_t       decrypt;
146  cipher_set_iv_func_t        set_iv;
147  char                       *description;
148  int                         ref_count;
149  cipher_test_case_t         *test_data;
150  debug_module_t             *debug;
151  cipher_type_id_t            id;
152} cipher_type_t;
153
154/*
155 * cipher_t defines an instantiation of a particular cipher, with fixed
156 * key length, key and salt values
157 */
158
159typedef struct cipher_t {
160  cipher_type_t *type;
161  void          *state;
162  int            key_len;
163#ifdef FORCE_64BIT_ALIGN
164  int            pad;
165#endif
166} cipher_t;
167
168/* some syntactic sugar on these function types */
169
170#define cipher_type_alloc(ct, c, klen) ((ct)->alloc((c), (klen)))
171
172#define cipher_dealloc(c) (((c)->type)->dealloc(c))
173
174#define cipher_init(c, k, dir) (((c)->type)->init(((c)->state), (k), ((c)->key_len), (dir)))
175
176#define cipher_encrypt(c, buf, len) \
177        (((c)->type)->encrypt(((c)->state), (buf), (len)))
178
179#define cipher_decrypt(c, buf, len) \
180        (((c)->type)->decrypt(((c)->state), (buf), (len)))
181
182#define cipher_set_iv(c, n)                           \
183  ((c) ? (((c)->type)->set_iv(((cipher_pointer_t)(c)->state), (n))) :   \
184                                err_status_no_such_op)
185
186err_status_t
187cipher_output(cipher_t *c, uint8_t *buffer, int num_octets_to_output);
188
189
190/* some bookkeeping functions */
191
192int
193cipher_get_key_length(const cipher_t *c);
194
195
196/*
197 * cipher_type_self_test() tests a cipher against test cases provided in
198 * an array of values of key/xtd_seq_num_t/plaintext/ciphertext
199 * that is known to be good
200 */
201
202err_status_t
203cipher_type_self_test(const cipher_type_t *ct);
204
205
206/*
207 * cipher_type_test() tests a cipher against external test cases provided in
208 * an array of values of key/xtd_seq_num_t/plaintext/ciphertext
209 * that is known to be good
210 */
211
212err_status_t
213cipher_type_test(const cipher_type_t *ct, const cipher_test_case_t *test_data);
214
215
216/*
217 * cipher_bits_per_second(c, l, t) computes (and estimate of) the
218 * number of bits that a cipher implementation can encrypt in a second
219 *
220 * c is a cipher (which MUST be allocated and initialized already), l
221 * is the length in octets of the test data to be encrypted, and t is
222 * the number of trials
223 *
224 * if an error is encountered, then the value 0 is returned
225 */
226
227uint64_t
228cipher_bits_per_second(cipher_t *c, int octets_in_buffer, int num_trials);
229
230#endif /* CIPHER_H */
231