view libtomcrypt/src/prngs/rng_make_prng.c @ 1156:a8f4dade70e5

avoid getpass when not used some systems (like android's bionic) do not provide getpass. you can disable ENABLE_CLI_PASSWORD_AUTH & ENABLE_CLI_INTERACT_AUTH to avoid its use (and rely on pubkey auth), but the link still fails because the support file calls getpass. do not define this func if both of those auth methods are not used.
author Mike Frysinger <vapier@gentoo.org>
date Wed, 21 Oct 2015 22:39:55 +0800
parents 0cbe8f6dbf9e
children f849a5ca2efc
line wrap: on
line source

/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 *
 * Tom St Denis, [email protected], http://libtomcrypt.com
 */
#include "tomcrypt.h"

/** 
  @file rng_make_prng.c
  portable way to get secure random bits to feed a PRNG  (Tom St Denis)
*/

/**
  Create a PRNG from a RNG
  @param bits     Number of bits of entropy desired (64 ... 1024)
  @param wprng    Index of which PRNG to setup
  @param prng     [out] PRNG state to initialize
  @param callback A pointer to a void function for when the RNG is slow, this can be NULL
  @return CRYPT_OK if successful
*/  
int rng_make_prng(int bits, int wprng, prng_state *prng, 
                  void (*callback)(void))
{
   unsigned char buf[256];
   int err;
   
   LTC_ARGCHK(prng != NULL);

   /* check parameter */
   if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
      return err;
   }

   if (bits < 64 || bits > 1024) {
      return CRYPT_INVALID_PRNGSIZE;
   }

   if ((err = prng_descriptor[wprng].start(prng)) != CRYPT_OK) {
      return err;
   }

   bits = ((bits/8)+((bits&7)!=0?1:0)) * 2;
   if (rng_get_bytes(buf, (unsigned long)bits, callback) != (unsigned long)bits) {
      return CRYPT_ERROR_READPRNG;
   }

   if ((err = prng_descriptor[wprng].add_entropy(buf, (unsigned long)bits, prng)) != CRYPT_OK) {
      return err;
   }

   if ((err = prng_descriptor[wprng].ready(prng)) != CRYPT_OK) {
      return err;
   }

   #ifdef LTC_CLEAN_STACK
      zeromem(buf, sizeof(buf));
   #endif
   return CRYPT_OK;
}


/* $Source: /cvs/libtom/libtomcrypt/src/prngs/rng_make_prng.c,v $ */
/* $Revision: 1.4 $ */
/* $Date: 2006/03/31 14:15:35 $ */