urbit/pkg/urcrypt/scrypt/slowequals.c

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#include <string.h>
/* Implements a constant time version of strcmp()
* Will return 1 if a and b are equal, 0 if they are not */
int slow_equals(const char* a, const char* b)
{
size_t lena, lenb, diff, i;
lena = strlen(a);
lenb = strlen(b);
diff = strlen(a) ^ strlen(b);
for(i=0; i<lena && i<lenb; i++)
{
diff |= a[i] ^ b[i];
}
if (diff == 0)
{
return 1;
}
else
{
return 0;
}
}