Re: Bitcoin puzzle transaction ~32 BTC prize to who solves it
For the #57 key instead:
I use 32 bit for the exponent (32 > 28) and I store only the first 64 bit of the x coordinate (there is a low chance to have a partial collision in a list of 2^28 element, i.e. two different x with the same first 64 bit) --> (64 + 32 bit)
To avoid any collisions you should use always 256 bit for the x coordinate. And the size of the hash table should be at least two times the size of the list you want to store.
Code:
#define GSTEP (1<<28)
typedef struct hashtable_entry {
uint64_t x;
uint32_t exponent;
} hashtable_entry;
#define HASH_SIZE (2*GSTEP)
hashtable_entry table[HASH_SIZE];
typedef struct hashtable_entry {
uint64_t x;
uint32_t exponent;
} hashtable_entry;
#define HASH_SIZE (2*GSTEP)
hashtable_entry table[HASH_SIZE];
I use 32 bit for the exponent (32 > 28) and I store only the first 64 bit of the x coordinate (there is a low chance to have a partial collision in a list of 2^28 element, i.e. two different x with the same first 64 bit) --> (64 + 32 bit)
To avoid any collisions you should use always 256 bit for the x coordinate. And the size of the hash table should be at least two times the size of the list you want to store.
Thanks again arulbero. Now I see why you're legendary.
