bool KG_GeneratePvtY(int level, char* keytemplate, char* pvt_text, char* y_text)
{
char tmp[256] = "";
BigInt p, p1, pub, pvt, y, temp, temp2;
int size, keysystem;
if(level == 29)
{
char basepoint_text[10] = "", public_x_text[100] = "", public_y_text[100] = "";
KG_GenerateEcdsaParameters(keytemplate, pvt_text, basepoint_text, public_x_text, public_y_text);
sprintf(y_text, "%s,%s,%s", basepoint_text, public_x_text, public_y_text);
return true;
}
else if(level >= 20)
{
keysystem = KS_SHORTV3;
level = level - 20;
if(level > 8)
return false;
}
else if(level >= 10)
{
keysystem = KS_V3;
level = level - 10;
if(level > 8)
return false;
}
else
{
keysystem = KS_V2;
if(level<0 or level>3)
return false;
}
size = level + 4;
p = BigInt_Create();
p1 = BigInt_Create();
pub = BigInt_Create();
pvt = BigInt_Create();
y = BigInt_Create();
temp = BigInt_Create();
temp2 = BigInt_Create();
BigInt_Set(temp, 1);
BigInt_Shift(temp, size * 8, p);
BigInt_Set(temp, primeoffsets[level]);
BigInt_Add(p, temp, temp2);
BigInt_Copy(p, temp2);
BigInt_Subtract(p, BigInt_One(), p1);
sprintf(tmp, "%u Level Public Key", level);
GenerateKeyNumberFromString(tmp, p, &pub, keysystem, ((keysystem == KS_V3 || keysystem == KS_SHORTV3) ? level + 1 : 0));
GenerateKeyNumberFromString(keytemplate, p, &pvt, keysystem, ((keysystem == KS_V3 || keysystem == KS_SHORTV3) ? level + 1 : 0));
BigInt_ToString(pvt, 16, pvt_text);
BigInt_PowerModulus(pub, pvt, p, y);
BigInt_ToString(y, 16, y_text);
BigInt_Destroy(temp2);
BigInt_Destroy(temp);
BigInt_Destroy(y);
BigInt_Destroy(pvt);
BigInt_Destroy(pub);
BigInt_Destroy(p1);
BigInt_Destroy(p);
return true;
}
int BigInt_Divide(BigInt a, BigInt b, BigInt answer, BigInt remainder)
{
//TODO: fix something here (memleak temp1 or t)
int compare, i, signa, signb;
WORKING_DIGIT high, low, t;
BigInt temp1, temp2;
temp1=BigInt_Create();
temp2=BigInt_Create();
signa=a->negative;
a->negative=0;
signb=b->negative;
b->negative=0;
/* Check for divide-by-zero, it's not allowed */
if(b->length==1 && b->digits[0]==0) return 0;
/* Compare a and b, to see if we can take a shortcut */
compare=BigInt_Compare_SignOptional(a, b, 1);
if(compare<0)
{
BigInt_Set(answer, 0);
BigInt_Copy(remainder, a);
return 1;
}
else if(compare==0)
{
BigInt_Set(answer, 1);
BigInt_Set(remainder, 0);
return 1;
}
BigInt_Realloc(answer, a->length, 0);
BigInt_Set(remainder, 0);
for(i=1; i<=a->length; ++i)
{
/* remainder=(remainder<<BITS_PER_DIGIT)+a->digits[a->length-i]; */
BigInt_Copy(temp1, remainder);
BigInt_Shift(temp1, BITS_PER_DIGIT, remainder);
remainder->digits[0]=a->digits[a->length-i];
if(BigInt_Compare_SignOptional(remainder, b, 1)>=0)
{
high=OVERFLOW_DIGIT;
low=0;
while(low<high)
{
t=((high-low)/2)+low;
/* if ((b*t)>remainder) high=t; else low=t+1; */
BigInt_Set(temp2, t);
BigInt_Multiply(b, temp2, temp1);
if(BigInt_Compare(temp1, remainder)>0) high=t;
else low=t+1;
}
t=low-1;
answer->digits[a->length-i]=(DIGIT)(t);
/* remainder=remainder-(b*t) */
BigInt_Set(temp2, t);
BigInt_Multiply(b, temp2, temp1);
BigInt_Subtract(remainder, temp1, temp2);
BigInt_Copy(remainder, temp2);
}
else answer->digits[a->length-i]=0;
}
a->negative=signa;
b->negative=signb;
answer->negative=(a->negative ^ b->negative);
BigInt_FindMSD(answer);
BigInt_Destroy(temp2);
BigInt_Destroy(temp1);
return 1;
}
