devendranaga

#include <iostream>

void (*mem_fun_cb)(void);

class mem_fun {
    private:
    public:
        mem_fun() { }
        ~mem_fun() { }

devendranaga

#include <iostream>
#include <functional>

void f()
{
    std::cout << "called f" << std::endl;
}

int main()
{

devendranaga

// callback declaration
void (*callback)(int);

void print_func(int a)
{
    printf("%d\n", a);
}

int register_print_callback()
{

devendranaga

static void (*event_callback)(void *user_priv, uint8_t *datap, size_t datap_len);
static void *user_priv;

int register_event_callback(void *user_ptr)
{
    event_callback = my_event_callback;
    user_priv = user_ptr;

    return 0;
}

devendranaga

#include <iostream>
#include <string>
#include <openssl/evp.h>
#include <openssl/err.h>
#include <openssl/ecdsa.h>
#include <openssl/ec.h>
#include <openssl/conf.h>
#include <openssl/rand.h>
#include <openssl/pem.h>
#include <openssl/sha.h>

devendranaga

int generate_keys(std::string pubkeyfile, std::string privkeyfile, std::string curve_name)
{
    EC_KEY *keygen;
    int nid = to_nid(curve_name);

    if (nid == -1) {
        return -1;
    }

    // get curve name

devendranaga

// loads in the pubkey
int load_pubkey(std::string pubkey)
{
    FILE *fp;

    // load in the keys
    fp = fopen(pubkey.c_str(), "r");
    if (!fp) {
        return -1;
    }

devendranaga

int load_privkey(std::string privkey)
{
    FILE *fp;

    fp = fopen(privkey.c_str(), "r");
    if (!fp) {
        return -1;
    }

    privatekey = PEM_read_ECPrivateKey(fp, NULL, NULL, NULL);

devendranaga

int sign(uint8_t *msg, size_t msglen, std::string sha_alg)
{
    if (!evp_sign_key || !privatekey) {
        std::cerr << "invalid sign key or private key is not loaded" << std::endl;
        return -1;
    }

    const EVP_MD *md;

    // mark the sha alg to use

devendranaga

int verify(uint8_t *msg, size_t msglen, uint8_t *signature, size_t signature_len, std::string sha_alg)
{
    if (!msg || !signature) {
        std::cerr << "invalid msg or signature" << std::endl;
        return -1;
    }

    const EVP_MD *md;

    if (sha_alg == "sha256") {