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      1 /*
      2  * xfm.h
      3  *
      4  * interface for abstract crypto transform
      5  *
      6  * David A. McGrew
      7  * Cisco Systems, Inc.
      8  */
      9 
     10 #ifndef XFM_H
     11 #define XFM_H
     12 
     13 #include "crypto_kernel.h"
     14 #include "err.h"
     15 
     16 /**
     17  * @defgroup Crypto Cryptography
     18  *
     19  * A simple interface to an abstract cryptographic transform that
     20  * provides both confidentiality and message authentication.
     21  *
     22  * @{
     23  */
     24 
     25 /**
     26  * @brief applies a crypto transform
     27  *
     28  * The function pointer xfm_func_t points to a function that
     29  * implements a crypto transform, and provides a uniform API for
     30  * accessing crypto mechanisms.
     31  *
     32  * @param key       location of secret key
     33  *
     34  * @param clear     data to be authenticated only
     35  *
     36  * @param clear_len length of data to be authenticated only
     37  *
     38  * @param iv        location to write the Initialization Vector (IV)
     39  *
     40  * @param protect   location of the data to be encrypted and
     41  * authenticated (before the function call), and the ciphertext
     42  * and authentication tag (after the call)
     43  *
     44  * @param protected_len location of the length of the data to be
     45  * encrypted and authenticated (before the function call), and the
     46  * length of the ciphertext (after the call)
     47  *
     48  * @param auth_tag   location to write auth tag
     49  */
     50 
     51 typedef err_status_t (*xfm_func_t)
     52      (void *key,
     53       void *clear,
     54       unsigned clear_len,
     55       void *iv,
     56       void *protect,
     57       unsigned *protected_len,
     58       void *auth_tag
     59       );
     60 
     61 typedef
     62 err_status_t (*xfm_inv_t)
     63      (void *key,            /* location of secret key                  */
     64       void *clear,          /* data to be authenticated only           */
     65       unsigned clear_len,   /* length of data to be authenticated only */
     66       void *iv,             /* location of iv                          */
     67       void *opaque,         /* data to be decrypted and authenticated  */
     68       unsigned *opaque_len, /* location of the length of data to be
     69 			     * decrypted and authd (before and after)
     70 			     */
     71       void *auth_tag        /* location of auth tag                    */
     72       );
     73 
     74 typedef struct xfm_ctx_t {
     75   xfm_func_t func;
     76   xfm_inv_t  inv;
     77   unsigned key_len;
     78   unsigned iv_len;
     79   unsigned auth_tag_len;
     80 } xfm_ctx_t;
     81 
     82 typedef xfm_ctx_t *xfm_t;
     83 
     84 #define xfm_get_key_len(xfm) ((xfm)->key_len)
     85 
     86 #define xfm_get_iv_len(xfm) ((xfm)->iv_len)
     87 
     88 #define xfm_get_auth_tag_len(xfm) ((xfm)->auth_tag_len)
     89 
     90 
     91 /* cryptoalgo - 5/28 */
     92 
     93 typedef err_status_t (*cryptoalg_func_t)
     94      (void *key,
     95       void *clear,
     96       unsigned clear_len,
     97       void *iv,
     98       void *opaque,
     99       unsigned *opaque_len
    100       );
    101 
    102 typedef
    103 err_status_t (*cryptoalg_inv_t)
    104      (void *key,            /* location of secret key                  */
    105       void *clear,          /* data to be authenticated only           */
    106       unsigned clear_len,   /* length of data to be authenticated only */
    107       void *iv,             /* location of iv                          */
    108       void *opaque,         /* data to be decrypted and authenticated  */
    109       unsigned *opaque_len  /* location of the length of data to be
    110 			     * decrypted and authd (before and after)
    111 			     */
    112       );
    113 
    114 typedef struct cryptoalg_ctx_t {
    115   cryptoalg_func_t enc;
    116   cryptoalg_inv_t  dec;
    117   unsigned key_len;
    118   unsigned iv_len;
    119   unsigned auth_tag_len;
    120   unsigned max_expansion;
    121 } cryptoalg_ctx_t;
    122 
    123 typedef cryptoalg_ctx_t *cryptoalg_t;
    124 
    125 #define cryptoalg_get_key_len(cryptoalg) ((cryptoalg)->key_len)
    126 
    127 #define cryptoalg_get_iv_len(cryptoalg) ((cryptoalg)->iv_len)
    128 
    129 #define cryptoalg_get_auth_tag_len(cryptoalg) ((cryptoalg)->auth_tag_len)
    130 
    131 
    132 
    133 /**
    134  * @}
    135  */
    136 
    137 #endif /* XFM_H */
    138 
    139 
    140