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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2016 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_RANDOM_H
#define BITCOIN_RANDOM_H
#include "uint256.h"
#include <stdint.h>
/* Seed OpenSSL PRNG with additional entropy data */
void RandAddSeed();
/**
* Functions to gather random data via the OpenSSL PRNG
*/
void GetRandBytes(unsigned char* buf, int num);
uint64_t GetRand(uint64_t nMax);
int GetRandInt(int nMax);
uint256 GetRandHash();
/**
* Function to gather random data from multiple sources, failing whenever any
* of those source fail to provide a result.
*/
void GetStrongRandBytes(unsigned char* buf, int num);
/**
* Fast randomness source. This is seeded once with secure random data, but
* is completely deterministic and insecure after that.
* This class is not thread-safe.
*/
class FastRandomContext {
public:
explicit FastRandomContext(bool fDeterministic=false);
uint32_t rand32() {
Rz = 36969 * (Rz & 65535) + (Rz >> 16);
Rw = 18000 * (Rw & 65535) + (Rw >> 16);
return (Rw << 16) + Rz;
}
bool randbool() {
return rand32() & 1;
}
uint32_t Rz;
uint32_t Rw;
};
/* Number of random bytes returned by GetOSRand.
* When changing this constant make sure to change all call sites, and make
* sure that the underlying OS APIs for all platforms support the number.
* (many cap out at 256 bytes).
*/
static const ssize_t NUM_OS_RANDOM_BYTES = 32;
/** Get 32 bytes of system entropy. Do not use this in application code: use
* GetStrongRandBytes instead.
*/
void GetOSRand(unsigned char *ent32);
/** Check that OS randomness is available and returning the requested number
* of bytes.
*/
bool Random_SanityCheck();
#endif // BITCOIN_RANDOM_H
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