21e00e9050
7e6dcd9 random: Add fallback if getrandom syscall not available (Wladimir J. van der Laan) 7cad849 sanity: Move OS random to sanity check function (Wladimir J. van der Laan) aa09ccb squashme: comment that NUM_OS_RANDOM_BYTES should not be changed lightly (Wladimir J. van der Laan) 224e6eb util: Specific GetOSRandom for Linux/FreeBSD/OpenBSD (Wladimir J. van der Laan) Tree-SHA512: 9fd408b1316c69de86674f342339b2f89192fd317c8c036b5df4320f828fa263c7966146bfc1904c51137ee4a26e4cb0f560b2cd05e18cde4d808b9b92ad15c4
77 lines
2.0 KiB
C++
77 lines
2.0 KiB
C++
// Copyright (c) 2009-2010 Satoshi Nakamoto
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// Copyright (c) 2009-2014 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#ifndef BITCOIN_RANDOM_H
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#define BITCOIN_RANDOM_H
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#include "uint256.h"
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#include <stdint.h>
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/* Seed OpenSSL PRNG with additional entropy data */
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void RandAddSeed();
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/**
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* Functions to gather random data via the OpenSSL PRNG
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*/
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void GetRandBytes(unsigned char* buf, int num);
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uint64_t GetRand(uint64_t nMax);
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int GetRandInt(int nMax);
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uint256 GetRandHash();
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bool GetRandBool(double rate);
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/**
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* Function to gather random data from multiple sources, failing whenever any
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* of those source fail to provide a result.
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*/
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void GetStrongRandBytes(unsigned char* buf, int num);
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/**
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* Fast randomness source. This is seeded once with secure random data, but
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* is completely deterministic and insecure after that.
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* This class is not thread-safe.
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*/
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class FastRandomContext {
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public:
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explicit FastRandomContext(bool fDeterministic=false);
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uint32_t rand32() {
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Rz = 36969 * (Rz & 65535) + (Rz >> 16);
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Rw = 18000 * (Rw & 65535) + (Rw >> 16);
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return (Rw << 16) + Rz;
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}
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uint32_t rand32(uint32_t nMax) {
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return rand32() % nMax;
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}
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uint32_t operator()(uint32_t nMax) {
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return rand32(nMax);
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}
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uint32_t Rz;
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uint32_t Rw;
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};
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/* Number of random bytes returned by GetOSRand.
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* When changing this constant make sure to change all call sites, and make
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* sure that the underlying OS APIs for all platforms support the number.
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* (many cap out at 256 bytes).
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*/
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static const ssize_t NUM_OS_RANDOM_BYTES = 32;
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/** Get 32 bytes of system entropy. Do not use this in application code: use
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* GetStrongRandBytes instead.
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*/
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void GetOSRand(unsigned char *ent32);
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/** Check that OS randomness is available and returning the requested number
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* of bytes.
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*/
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bool Random_SanityCheck();
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#endif // BITCOIN_RANDOM_H
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