osrng.h

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// osrng.h - written and placed in the public domain by Wei Dai


#ifndef CRYPTOPP_OSRNG_H
#define CRYPTOPP_OSRNG_H

#include "config.h"

#if !defined(OS_NO_DEPENDENCE) && defined(OS_RNG_AVAILABLE)

#include "cryptlib.h"
#include "randpool.h"
#include "smartptr.h"
#include "fips140.h"
#include "rng.h"
#include "aes.h"
#include "sha.h"

NAMESPACE_BEGIN(CryptoPP)

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();

// type HCRYPTPROV and BCRYPT_ALG_HANDLE, avoid #include <windows.h>
#if defined(USE_MS_CRYPTOAPI)
# if defined(__CYGWIN__) && defined(__x86_64__)
        typedef unsigned long long ProviderHandle;
# elif defined(WIN64) || defined(_WIN64)
        typedef unsigned __int64 ProviderHandle;
# else
        typedef unsigned long ProviderHandle;
# endif
#elif defined(USE_MS_CNGAPI)
        typedef void *PVOID;
        typedef PVOID ProviderHandle;
#endif // USE_MS_CRYPTOAPI or USE_MS_CNGAPI

        ProviderHandle GetProviderHandle() const {return m_hProvider;}

private:
        ProviderHandle m_hProvider;
};

#if defined(_MSC_VER) && defined(USE_MS_CRYPTOAPI)
# pragma comment(lib, "advapi32.lib")
#endif

#if defined(_MSC_VER) && defined(USE_MS_CNGAPI)
# pragma comment(lib, "bcrypt.lib")
#endif

#endif //CRYPTOPP_WIN32_AVAILABLE

class CRYPTOPP_DLL NonblockingRng : public RandomNumberGenerator
{
public:
        NonblockingRng();
        ~NonblockingRng();

        void GenerateBlock(byte *output, size_t size);

protected:
#ifdef CRYPTOPP_WIN32_AVAILABLE
        MicrosoftCryptoProvider m_Provider;
#else
        int m_fd;
#endif
};

#endif

#if defined(BLOCKING_RNG_AVAILABLE) || defined(CRYPTOPP_DOXYGEN_PROCESSING)

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);


class CRYPTOPP_DLL AutoSeededRandomPool : public RandomPool
{
public:
        explicit AutoSeededRandomPool(bool blocking = false, unsigned int seedSize = 32)
                {Reseed(blocking, seedSize);}

        void Reseed(bool blocking = false, unsigned int seedSize = 32);
};

template <class BLOCK_CIPHER>
class AutoSeededX917RNG : public RandomNumberGenerator, public NotCopyable
{
public:
        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);

        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>;

#if defined(CRYPTOPP_DOXYGEN_PROCESSING)
class DefaultAutoSeededRNG {}
#else
// 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
#endif // CRYPTOPP_DOXYGEN_PROCESSING

NAMESPACE_END

#endif

#endif