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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  */

 #include "crypto.h"		/* for cipher_type_id_t */

 #include "crypto_types.h"	/* for values of cipher_type_id_t */

 /**

  * @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, int key_len, 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_iv_func_t function sets the current initialization vector

  */

 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_id_t            id;

 } 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), ((c)->key_len), (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_type_test() tests a cipher against external 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_test(const cipher_type_t *ct, const cipher_test_case_t *test_data);

 /*

  * 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 */