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      1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
      2  *
      3  * LibTomCrypt is a library that provides various cryptographic
      4  * algorithms in a highly modular and flexible manner.
      5  *
      6  * The library is free for all purposes without any express
      7  * guarantee it works.
      8  *
      9  * Tom St Denis, tomstdenis (at) gmail.com, http://libtomcrypt.com
     10  */
     11 #include "tomcrypt.h"
     12 
     13 /**
     14    @file sprng.c
     15    Secure PRNG, Tom St Denis
     16 */
     17 
     18 /* A secure PRNG using the RNG functions.  Basically this is a
     19  * wrapper that allows you to use a secure RNG as a PRNG
     20  * in the various other functions.
     21  */
     22 
     23 #ifdef SPRNG
     24 
     25 const struct ltc_prng_descriptor sprng_desc =
     26 {
     27     "sprng", 0,
     28     &sprng_start,
     29     &sprng_add_entropy,
     30     &sprng_ready,
     31     &sprng_read,
     32     &sprng_done,
     33     &sprng_export,
     34     &sprng_import,
     35     &sprng_test
     36 };
     37 
     38 /**
     39   Start the PRNG
     40   @param prng     [out] The PRNG state to initialize
     41   @return CRYPT_OK if successful
     42 */
     43 int sprng_start(prng_state *prng)
     44 {
     45    return CRYPT_OK;
     46 }
     47 
     48 /**
     49   Add entropy to the PRNG state
     50   @param in       The data to add
     51   @param inlen    Length of the data to add
     52   @param prng     PRNG state to update
     53   @return CRYPT_OK if successful
     54 */
     55 int sprng_add_entropy(const unsigned char *in, unsigned long inlen, prng_state *prng)
     56 {
     57    return CRYPT_OK;
     58 }
     59 
     60 /**
     61   Make the PRNG ready to read from
     62   @param prng   The PRNG to make active
     63   @return CRYPT_OK if successful
     64 */
     65 int sprng_ready(prng_state *prng)
     66 {
     67    return CRYPT_OK;
     68 }
     69 
     70 /**
     71   Read from the PRNG
     72   @param out      Destination
     73   @param outlen   Length of output
     74   @param prng     The active PRNG to read from
     75   @return Number of octets read
     76 */
     77 unsigned long sprng_read(unsigned char *out, unsigned long outlen, prng_state *prng)
     78 {
     79    LTC_ARGCHK(out != NULL);
     80    return rng_get_bytes(out, outlen, NULL);
     81 }
     82 
     83 /**
     84   Terminate the PRNG
     85   @param prng   The PRNG to terminate
     86   @return CRYPT_OK if successful
     87 */
     88 int sprng_done(prng_state *prng)
     89 {
     90    return CRYPT_OK;
     91 }
     92 
     93 /**
     94   Export the PRNG state
     95   @param out       [out] Destination
     96   @param outlen    [in/out] Max size and resulting size of the state
     97   @param prng      The PRNG to export
     98   @return CRYPT_OK if successful
     99 */
    100 int sprng_export(unsigned char *out, unsigned long *outlen, prng_state *prng)
    101 {
    102    LTC_ARGCHK(outlen != NULL);
    103 
    104    *outlen = 0;
    105    return CRYPT_OK;
    106 }
    107 
    108 /**
    109   Import a PRNG state
    110   @param in       The PRNG state
    111   @param inlen    Size of the state
    112   @param prng     The PRNG to import
    113   @return CRYPT_OK if successful
    114 */
    115 int sprng_import(const unsigned char *in, unsigned long inlen, prng_state *prng)
    116 {
    117    return CRYPT_OK;
    118 }
    119 
    120 /**
    121   PRNG self-test
    122   @return CRYPT_OK if successful, CRYPT_NOP if self-testing has been disabled
    123 */
    124 int sprng_test(void)
    125 {
    126    return CRYPT_OK;
    127 }
    128 
    129 #endif
    130 
    131 
    132 
    133 
    134 /* $Source: /cvs/libtom/libtomcrypt/src/prngs/sprng.c,v $ */
    135 /* $Revision: 1.4 $ */
    136 /* $Date: 2006/03/31 14:15:35 $ */
    137