osrng.h
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#ifndef CRYPTOPP_OSRNG_H
#define CRYPTOPP_OSRNG_H
//! \file
#include "config.h"
#ifdef OS_RNG_AVAILABLE
#include "randpool.h"
#include "rng.h"
#include "aes.h"
#include "sha.h"
#include "fips140.h"
NAMESPACE_BEGIN(CryptoPP)
//! Exception class for Operating-System Random Number Generator.
class CRYPTOPP_DLL OS_RNG_Err : public Exception
{
public:
OS_RNG_Err(const std::string &operation);
};
#ifdef NONBLOCKING_RNG_AVAILABLE
#ifdef CRYPTOPP_WIN32_AVAILABLE
class CRYPTOPP_DLL MicrosoftCryptoProvider
{
public:
MicrosoftCryptoProvider();
~MicrosoftCryptoProvider();
#if defined(_WIN64)
typedef unsigned __int64 ProviderHandle; // type HCRYPTPROV, avoid #include <windows.h>
#else
typedef unsigned long ProviderHandle;
#endif
ProviderHandle GetProviderHandle() const {return m_hProvider;}
private:
ProviderHandle m_hProvider;
};
#pragma comment(lib, "advapi32.lib")
#endif
//! encapsulate CryptoAPI's CryptGenRandom or /dev/urandom
class CRYPTOPP_DLL NonblockingRng : public RandomNumberGenerator
{
public:
NonblockingRng();
~NonblockingRng();
void GenerateBlock(byte *output, size_t size);
protected:
#ifdef CRYPTOPP_WIN32_AVAILABLE
# ifndef WORKAROUND_MS_BUG_Q258000
MicrosoftCryptoProvider m_Provider;
# endif
#else
int m_fd;
#endif
};
#endif
#ifdef BLOCKING_RNG_AVAILABLE
//! encapsulate /dev/random, or /dev/srandom on OpenBSD
class CRYPTOPP_DLL BlockingRng : public RandomNumberGenerator
{
public:
BlockingRng();
~BlockingRng();
void GenerateBlock(byte *output, size_t size);
protected:
int m_fd;
};
#endif
CRYPTOPP_DLL void CRYPTOPP_API OS_GenerateRandomBlock(bool blocking, byte *output, size_t size);
//! Automaticly Seeded Randomness Pool
/*! This class seeds itself using an operating system provided RNG. */
class CRYPTOPP_DLL AutoSeededRandomPool : public RandomPool
{
public:
//! use blocking to choose seeding with BlockingRng or NonblockingRng. the parameter is ignored if only one of these is available
explicit AutoSeededRandomPool(bool blocking = false, unsigned int seedSize = 32)
{Reseed(blocking, seedSize);}
void Reseed(bool blocking = false, unsigned int seedSize = 32);
};
//! RNG from ANSI X9.17 Appendix C, seeded using an OS provided RNG
template <class BLOCK_CIPHER>
class AutoSeededX917RNG : public RandomNumberGenerator, public NotCopyable
{
public:
//! use blocking to choose seeding with BlockingRng or NonblockingRng. the parameter is ignored if only one of these is available
explicit AutoSeededX917RNG(bool blocking = false, bool autoSeed = true)
{if (autoSeed) Reseed(blocking);}
void Reseed(bool blocking = false, const byte *additionalEntropy = NULL, size_t length = 0);
// exposed for testing
void Reseed(const byte *key, size_t keylength, const byte *seed, const byte *timeVector);
bool CanIncorporateEntropy() const {return true;}
void IncorporateEntropy(const byte *input, size_t length) {Reseed(false, input, length);}
void GenerateIntoBufferedTransformation(BufferedTransformation &target, const std::string &channel, lword length) {m_rng->GenerateIntoBufferedTransformation(target, channel, length);}
private:
member_ptr<RandomNumberGenerator> m_rng;
};
template <class BLOCK_CIPHER>
void AutoSeededX917RNG<BLOCK_CIPHER>::Reseed(const byte *key, size_t keylength, const byte *seed, const byte *timeVector)
{
m_rng.reset(new X917RNG(new typename BLOCK_CIPHER::Encryption(key, keylength), seed, timeVector));
}
template <class BLOCK_CIPHER>
void AutoSeededX917RNG<BLOCK_CIPHER>::Reseed(bool blocking, const byte *input, size_t length)
{
SecByteBlock seed(BLOCK_CIPHER::BLOCKSIZE + BLOCK_CIPHER::DEFAULT_KEYLENGTH);
const byte *key;
do
{
OS_GenerateRandomBlock(blocking, seed, seed.size());
if (length > 0)
{
SHA256 hash;
hash.Update(seed, seed.size());
hash.Update(input, length);
hash.TruncatedFinal(seed, UnsignedMin(hash.DigestSize(), seed.size()));
}
key = seed + BLOCK_CIPHER::BLOCKSIZE;
} // check that seed and key don't have same value
while (memcmp(key, seed, STDMIN((unsigned int)BLOCK_CIPHER::BLOCKSIZE, (unsigned int)BLOCK_CIPHER::DEFAULT_KEYLENGTH)) == 0);
Reseed(key, BLOCK_CIPHER::DEFAULT_KEYLENGTH, seed, NULL);
}
CRYPTOPP_DLL_TEMPLATE_CLASS AutoSeededX917RNG<AES>;
//! this is AutoSeededX917RNG\<AES\> in FIPS mode, otherwise it's AutoSeededRandomPool
#if CRYPTOPP_ENABLE_COMPLIANCE_WITH_FIPS_140_2
typedef AutoSeededX917RNG<AES> DefaultAutoSeededRNG;
#else
typedef AutoSeededRandomPool DefaultAutoSeededRNG;
#endif
NAMESPACE_END
#endif
#endif