#include <stdbool.h>

struct ProofOfWork {
    unsigned long int nonce;
    char *result;
};
bool is_valid_proof(unsigned long int nonce, char *result, char *phrase,
                    char *salt);

bool is_sufficient_difficulty(unsigned long int nonce, char *result, char *salt,
                              unsigned difficulty);

struct ProofOfWork prove_work(char *salt, char *phrase, unsigned difficulty);