rng.cpp

各种加密算法的集合

  
#include <memory.h> 
#include "misc.h" 
#include "rng.h" 
#include <time.h> 

// linear congruential generator 
// originally by William S. England 

// do not use for cryptographic purposes 

/* 
** Original_numbers are the original published m and q in the 
** ACM article above. John Burton has furnished numbers for 
** a reportedly better generator. The new numbers are now 
** used in this program by default. 
*/ 

#ifndef LCRNG_ORIGINAL_NUMBERS 
const word32 LC_RNG::m=2147483647L; 
const word32 LC_RNG::q=44488L; 

const word16 LC_RNG::a=(unsigned int)48271L; 
const word16 LC_RNG::r=3399; 
#else 
const word32 LC_RNG::m=2147483647L; 
const word32 LC_RNG::q=127773L; 

const word16 LC_RNG::a=16807; 
const word16 LC_RNG::r=2836; 
#endif 

byte LC_RNG::GetByte() 
{ 
word32 hi = seed/q; 
word32 lo = seed>q; 

long test = a*lo - r*hi; 

if (test > 0) 
seed = test; 
else 
seed = test+ m; 

return (seedptr[0] ^ seedptr[1] ^ seedptr[2] ^ seedptr[3]); 
} 

X917RNG::X917RNG(BlockTransformation *c, const byte *seed) 
: cipher(c), 
S(cipher->BlockSize()), 
dtbuf(SecAlloc(byte, 3*S)), 
randseed(dtbuf+S), 
randbuf(dtbuf+2*S), 
randbuf_counter(0) 
{ 
memcpy(randseed, seed, S); 
time_t tstamp1 = time(0); 
xorbuf(dtbuf, (byte *)&amt;tstamp1, min((int)sizeof(tstamp1), S)); 
cipher->ProcessBlock(dtbuf); 
clock_t tstamp2 = clock(); 
xorbuf(dtbuf, (byte *)&amt;tstamp2, min((int)sizeof(tstamp2), S)); 
cipher->ProcessBlock(dtbuf); 
} 

X917RNG::~X917RNG() 
{ 
delete cipher; 
SecFree(dtbuf, 3*S); 
} 

byte X917RNG::GetByte() 
{ 
if (randbuf_counter==0) 
{ 
// calculate new enciphered timestamp 
clock_t tstamp = clock(); 
xorbuf(dtbuf, (byte *)&amt;tstamp, min((int)sizeof(tstamp), S)); 
cipher->ProcessBlock(dtbuf); 

// combine enciphered timestamp with seed 
xorbuf(randseed, dtbuf, S); 

// generate a new block of random bytes 
cipher->ProcessBlock(randseed, randbuf); 

// compute new seed vector 
for (int i=0; i<S; i++) 
randseed[i] = randbuf[i] ^ dtbuf[i]; 
cipher->ProcessBlock(randseed); 

randbuf_counter=S; 
} 
return(randbuf[--randbuf_counter]); 
}