Mercurial > vba-linux

     1 // RandGen.cpp

     2 

     3 #include "StdAfx.h"

     4 

     5 #include <stdio.h>

     6 #include "Windows/Synchronization.h"

     7 #include "RandGen.h"

     8 

     9 #ifndef _WIN32

    10 #include <unistd.h>

    11 #define USE_POSIX_TIME

    12 #define USE_POSIX_TIME2

    13 #endif

    14 

    15 #ifdef USE_POSIX_TIME

    16 #include <time.h>

    17 #ifdef USE_POSIX_TIME2

    18 #include <sys/time.h>

    19 #endif

    20 #endif

    21 

    22 // This is not very good random number generator.

    23 // Please use it only for salt.

    24 // First generated data block depends from timer and processID.

    25 // Other generated data blocks depend from previous state

    26 // Maybe it's possible to restore original timer value from generated value.

    27 

    28 void CRandomGenerator::Init()

    29 {

    30   NCrypto::NSha1::CContext hash;

    31   hash.Init();

    32 

    33   #ifdef _WIN32

    34   DWORD w = ::GetCurrentProcessId();

    35   hash.Update((const Byte *)&w, sizeof(w));

    36   w = ::GetCurrentThreadId();

    37   hash.Update((const Byte *)&w, sizeof(w));

    38   #else

    39   pid_t pid = getpid();

    40   hash.Update((const Byte *)&pid, sizeof(pid));

    41   pid = getppid();

    42   hash.Update((const Byte *)&pid, sizeof(pid));

    43   #endif

    44 

    45   for (int i = 0; i < 1000; i++)

    46   {

    47     #ifdef _WIN32

    48     LARGE_INTEGER v;

    49     if (::QueryPerformanceCounter(&v))

    50       hash.Update((const Byte *)&v.QuadPart, sizeof(v.QuadPart));

    51     #endif

    52 

    53     #ifdef USE_POSIX_TIME

    54     #ifdef USE_POSIX_TIME2

    55     timeval v;

    56     if (gettimeofday(&v, 0) == 0)

    57     {

    58       hash.Update((const Byte *)&v.tv_sec, sizeof(v.tv_sec));

    59       hash.Update((const Byte *)&v.tv_usec, sizeof(v.tv_usec));

    60     }

    61     #endif

    62     time_t v2 = time(NULL);

    63     hash.Update((const Byte *)&v2, sizeof(v2));

    64     #endif

    65 

    66     DWORD tickCount = ::GetTickCount();

    67     hash.Update((const Byte *)&tickCount, sizeof(tickCount));

    68     

    69     for (int j = 0; j < 100; j++)

    70     {

    71       hash.Final(_buff);

    72       hash.Init();

    73       hash.Update(_buff, NCrypto::NSha1::kDigestSize);

    74     }

    75   }

    76   hash.Final(_buff);

    77   _needInit = false;

    78 }

    79 

    80 static NWindows::NSynchronization::CCriticalSection g_CriticalSection;

    81 

    82 void CRandomGenerator::Generate(Byte *data, unsigned int size)

    83 {

    84   g_CriticalSection.Enter();

    85   if (_needInit)

    86     Init();

    87   while (size > 0)

    88   {

    89     NCrypto::NSha1::CContext hash;

    90     

    91     hash.Init();

    92     hash.Update(_buff, NCrypto::NSha1::kDigestSize);

    93     hash.Final(_buff);

    94     

    95     hash.Init();

    96     UInt32 salt = 0xF672ABD1;

    97     hash.Update((const Byte *)&salt, sizeof(salt));

    98     hash.Update(_buff, NCrypto::NSha1::kDigestSize);

    99     Byte buff[NCrypto::NSha1::kDigestSize];

   100     hash.Final(buff);

   101     for (unsigned int i = 0; i < NCrypto::NSha1::kDigestSize && size > 0; i++, size--)

   102       *data++ = buff[i];

   103   }

   104   g_CriticalSection.Leave();

   105 }

   106 

   107 CRandomGenerator g_RandomGenerator;
author	Robert McIntyre <rlm@mit.edu>
date	Sat, 03 Mar 2012 10:31:27 -0600
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