src/random.h

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2014 The Bitcoin Core developers
   3 // Distributed under the MIT software license, see the accompanying
   4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5
   6 #ifndef BITCOIN_RANDOM_H
   7 #define BITCOIN_RANDOM_H
   8
   9 #include "uint256.h"
  10
  11 #include <stdint.h>
  12
  13 /* Seed OpenSSL PRNG with additional entropy data */
  14 void RandAddSeed();
  15
  16 /**
  17  * Functions to gather random data via the OpenSSL PRNG
  18  */
  19 void GetRandBytes(unsigned char* buf, int num);
  20 uint64_t GetRand(uint64_t nMax);
  21 int GetRandInt(int nMax);
  22 uint256 GetRandHash();
  23
  24 /**
  25  * Function to gather random data from multiple sources, failing whenever any
  26  * of those source fail to provide a result.
  27  */
  28 void GetStrongRandBytes(unsigned char* buf, int num);
  29
  30 /**
  31  * Seed insecure_rand using the random pool.
  32  * @param Deterministic Use a deterministic seed
  33  */
  34 void seed_insecure_rand(bool fDeterministic = false);
  35
  36 /**
  37  * MWC RNG of George Marsaglia
  38  * This is intended to be fast. It has a period of 2^59.3, though the
  39  * least significant 16 bits only have a period of about 2^30.1.
  40  *
  41  * @return random value
  42  */
  43 extern uint32_t insecure_rand_Rz;
  44 extern uint32_t insecure_rand_Rw;
  45 static inline uint32_t insecure_rand(void)
  46 {
  47     insecure_rand_Rz = 36969 * (insecure_rand_Rz & 65535) + (insecure_rand_Rz >> 16);
  48     insecure_rand_Rw = 18000 * (insecure_rand_Rw & 65535) + (insecure_rand_Rw >> 16);
  49     return (insecure_rand_Rw << 16) + insecure_rand_Rz;
  50 }
  51
  52 #endif // BITCOIN_RANDOM_H