/*
* Generate a random number with the ISAAC CSPRNG of
* given size
*
* out output array of with size >= given size
* size the size of the random number to generate in bytes
*/
void isaac_rand(unsigned char *out, const int size)
{
int i;
if(initRand !=1){
isaac_init();
initRand = 1;
}
for(i = 0; ((size)/32) > i; i++){
if(count < 1){
isaac();
count = 256;
}
count--;
memcpy(out+4*i, randrsl+count, 4);
}
if(size % 32 > 0){
if(count < 1){
isaac();
count = 256;
}
count--;
memcpy(out+4*i, randrsl+count, (size-1)/8+1);
}
}
uint32_t randomIsaac::getNext( void )
{
this->randomPoolCount--;
if ( this->randomPoolCount < 0 ) {
isaac();
this->randomPoolCount = poolSize - 1;
}
return this->randomPool[this->randomPoolCount];
}
/*
* Initialize the isaac CSPRNG with a seed
*/
void isaac_init(void)
{
srand ( time(NULL) );
randrsl[0] = rand(); //not secure, but good for now
randrsl[1] = rand();
randrsl[2] = rand();
randrsl[3] = rand();
randrsl[4] = rand();
randrsl[5] = rand();
randinit(1);
isaac();
count = 256;
}
/* if (flag==TRUE), then use the contents of randrsl[] to initialize mm[]. */
void randinit(randctx *ctx, word flag)
{
word i;
ub4 a,b,c,d,e,f,g,h;
ub4 *m,*r;
ctx->randa = ctx->randb = ctx->randc = 0;
m=ctx->randmem;
r=ctx->randrsl;
a=b=c=d=e=f=g=h=0x9e3779b9; /* the golden ratio */
for (i=0; i<4; ++i) /* scramble it */
{
mix(a,b,c,d,e,f,g,h);
}
if (flag)
{
/* initialize using the contents of r[] as the seed */
for (i=0; i<RANDSIZ; i+=8)
{
a+=r[i ]; b+=r[i+1]; c+=r[i+2]; d+=r[i+3];
e+=r[i+4]; f+=r[i+5]; g+=r[i+6]; h+=r[i+7];
mix(a,b,c,d,e,f,g,h);
m[i ]=a; m[i+1]=b; m[i+2]=c; m[i+3]=d;
m[i+4]=e; m[i+5]=f; m[i+6]=g; m[i+7]=h;
}
/* do a second pass to make all of the seed affect all of m */
for (i=0; i<RANDSIZ; i+=8)
{
a+=m[i ]; b+=m[i+1]; c+=m[i+2]; d+=m[i+3];
e+=m[i+4]; f+=m[i+5]; g+=m[i+6]; h+=m[i+7];
mix(a,b,c,d,e,f,g,h);
m[i ]=a; m[i+1]=b; m[i+2]=c; m[i+3]=d;
m[i+4]=e; m[i+5]=f; m[i+6]=g; m[i+7]=h;
}
}
else
{
/* fill in mm[] with messy stuff */
for (i=0; i<RANDSIZ; i+=8)
{
mix(a,b,c,d,e,f,g,h);
m[i ]=a; m[i+1]=b; m[i+2]=c; m[i+3]=d;
m[i+4]=e; m[i+5]=f; m[i+6]=g; m[i+7]=h;
}
}
isaac(ctx); /* fill in the first set of results */
ctx->randcnt=RANDSIZ; /* prepare to use the first set of results */
}
int main()
{
ub4 i,j;
randctx ctx;
ctx.randa=ctx.randb=ctx.randc=(ub4)0;
for (i=0; i<256; ++i) ctx.randrsl[i]=(ub4)0;
randinit(&ctx, TRUE);
for (i=0; i<2; ++i)
{
isaac(&ctx);
for (j=0; j<256; ++j)
{
printf("%.8lx",ctx.randrsl[j]);
if ((j&7)==7) printf("\n");
}
}
}
void QTIsaac<ALPHA,T>::randinit(randctx* ctx, bool bUseSeed)
{
T a,b,c,d,e,f,g,h;
a = b = c = d = e = f = g = h = GOLDEN_RATIO;
T* m = (ctx->randmem);
T* r = (ctx->randrsl);
if(!bUseSeed)
{
ctx->randa = 0;
ctx->randb = 0;
ctx->randc = 0;
}
// scramble it
for(int i=0; i < 4; ++i)
{
shuffle(a,b,c,d,e,f,g,h);
}
if(bUseSeed)
{
// initialize using the contents of r[] as the seed
for(i=0; i < N; i+=8)
{
a+=r[i ]; b+=r[i+1]; c+=r[i+2]; d+=r[i+3];
e+=r[i+4]; f+=r[i+5]; g+=r[i+6]; h+=r[i+7];
shuffle(a,b,c,d,e,f,g,h);
m[i ]=a; m[i+1]=b; m[i+2]=c; m[i+3]=d;
m[i+4]=e; m[i+5]=f; m[i+6]=g; m[i+7]=h;
}
//do a second pass to make all of the seed affect all of m
for(i=0; i < N; i += 8)
{
a+=m[i ]; b+=m[i+1]; c+=m[i+2]; d+=m[i+3];
e+=m[i+4]; f+=m[i+5]; g+=m[i+6]; h+=m[i+7];
shuffle(a,b,c,d,e,f,g,h);
m[i ]=a; m[i+1]=b; m[i+2]=c; m[i+3]=d;
m[i+4]=e; m[i+5]=f; m[i+6]=g; m[i+7]=h;
}
}
else
{
// fill in mm[] with messy stuff
shuffle(a,b,c,d,e,f,g,h);
m[i ]=a; m[i+1]=b; m[i+2]=c; m[i+3]=d;
m[i+4]=e; m[i+5]=f; m[i+6]=g; m[i+7]=h;
}
isaac(ctx); // fill in the first set of results
ctx->randcnt = N; // prepare to use the first set of results
}
inline T QTIsaac<ALPHA,T>::rand(void)
{
return(!m_rc.randcnt-- ? (isaac(&m_rc), m_rc.randcnt=(N-1), m_rc.randrsl[m_rc.randcnt]) : m_rc.randrsl[m_rc.randcnt]);
}
