bignum *bigdecrement(bignum *n,size_t by_n)
{
ABORT_NABN(n);
while(by_n--)
bigsub(n,&BIGONE,n);
return n;
}
/*
* DH stage 2-epsilon: given a number f, validate it to ensure it's in
* range. (RFC 4253 section 8: "Values of 'e' or 'f' that are not in
* the range [1, p-1] MUST NOT be sent or accepted by either side."
* Also, we rule out 1 and p-1 too, since that's easy to do and since
* they lead to obviously weak keys that even a passive eavesdropper
* can figure out.)
*/
const char *dh_validate_f(void *handle, Bignum f)
{
struct dh_ctx *ctx = (struct dh_ctx *)handle;
if (bignum_cmp(f, One) <= 0) {
return "f value received is too small";
} else {
Bignum pm1 = bigsub(ctx->p, One);
int cmp = bignum_cmp(f, pm1);
freebn(pm1);
if (cmp >= 0)
return "f value received is too large";
}
return NULL;
}
// Returns in r the solution of x == r[k] (mod m[k]), k = 0, ..., n-1
void crt (rawtype *r, rawtype *m, size_t n)
{
size_t t, k;
rawtype *mm = new rawtype[n], *x = new rawtype[n], *s = new rawtype[n];
modint y;
rawtype o;
o = modint::modulus;
mm[0] = m[0];
for (t = 1; t < n; t++)
mm[t] = bigmul (mm, mm, m[t], t);
for (t = 0; t < n; t++)
s[t] = 0;
for (k = 0; k < n; k++)
{
setmodulus (m[k]);
y = 1;
for (t = 0; t < n; t++)
if (t != k) y *= m[t];
y = r[k] / y;
bigdiv (x, mm, m[k], n);
x[n - 1] = bigmul (x, x, y, n - 1);
if (bigadd (s, x, n) || bigcmp (s, mm, n) > 0)
bigsub (s, mm, n);
}
moveraw (r, s, n);
setmodulus (o);
delete[] mm;
delete[] x;
delete[] s;
}
// Adds n words from s to d, returns overflow carry bit
rawtype baseadd (rawtype *dest, rawtype *src1, rawtype *src2, size_t len, rawtype carry)
{
size_t t;
for (t = len; t--;)
{
dest[t] = src1[t];
bigadd (dest + t, &carry, 1);
if ((src2 && bigadd (dest + t, src2 + t, 1) != 0) ||
bigcmp (dest + t, &Base, 1) >= 0)
{
bigsub (dest + t, &Base, 1);
carry = 1;
}
else
{
carry = 0;
}
}
return carry;
}
// Subtracts n words s from d, returns subtract carry bit (1)
rawtype basesub (rawtype *dest, rawtype *src1, rawtype *src2, size_t len, rawtype carry)
{
size_t t;
rawtype tmp;
for (t = len; t--;)
{
dest[t] = (src1 ? src1[t] : 0);
tmp = (src2 ? src2[t] : 0);
bigadd (&tmp, &carry, 1);
if (bigsub (dest + t, &tmp, 1) != 0)
{
bigadd (dest + t, &Base, 1);
carry = 1;
}
else
{
carry = 0;
}
}
return carry;
}
int main()
{
long j,n,l;
while(scanf("%s",str)==1&&strcmp(str,"0"))
{
j=strlen(str)-1;
l=j+1;
while(l>9)
{
n=str[j]-'0';
str[j]='\0';
bigsub(str,equ[n]);
j--;
l=strlen(str);
}
n=atol(str);
if((n==0)||(n>=17&&n%17==0))
printf("1");
else
printf("0");
printf("\n");
}
return 0;
}
