main.cpp

/*
This work is derived from:
https://github.com/I-Connect/nuki_ble

Therefore licence is: GPL v3.0

requirements:
GCC, libsodium

compile:
gcc main.cpp -lsodium

run:
./a.out
*/

#include <stdio.h>
#include <string.h>
#include <sodium.h>

typedef bool boolean;
#define byte uint8_t

unsigned char remotePublicKey[32] = {0x2F, 0xE5, 0x7D, 0xA3, 0x47, 0xCD, 0x62, 0x43, 0x15, 0x28, 0xDA, 0xAC, 0x5F, 0xBB, 0x29, 0x07, 0x30, 0xFF, 0xF6, 0x84, 0xAF, 0xC4, 0xCF, 0xC2, 0xED, 0x90, 0x99, 0x5F, 0x58, 0xCB, 0x3B, 0x74};
static unsigned char myPrivateKey[32] = {0x8C, 0xAA, 0x54, 0x67, 0x23, 0x07, 0xBF, 0xFD, 0xF5, 0xEA, 0x18, 0x3F, 0xC6, 0x07, 0x15, 0x8D, 0x20, 0x11, 0xD0, 0x08, 0xEC, 0xA6, 0xA1, 0x08, 0x86, 0x14, 0xFF, 0x08, 0x53, 0xA5, 0xAA, 0x07};
static unsigned char myPublicKey[32] = {0xF8, 0x81, 0x27, 0xCC, 0xF4, 0x80, 0x23, 0xB5, 0xCB, 0xE9, 0x10, 0x1D, 0x24, 0xBA, 0xA8, 0xA3, 0x68, 0xDA, 0x94, 0xE8, 0xC2, 0xE3, 0xCD, 0xE2, 0xDE, 0xD2, 0x9C, 0xE9, 0x6A, 0xB5, 0x0C, 0x15};

void printBuffer(const byte* buff, const uint8_t size, const boolean asChars, const char* header) {

  if (strlen(header) > 0) {
    printf ("%s", header);
    printf (": ");
  }
  for (int i = 0; i < size; i++) {
    if (asChars) {
      printf ("%c", (char)buff[i]);
    } else {
      printf ("%02x ", buff[i]);
    }
  }
  printf("\n");
}


int main(){
  unsigned char sharedKeyS[32];
  int i= crypto_scalarmult_curve25519(sharedKeyS, myPrivateKey, remotePublicKey);
  printBuffer(sharedKeyS, sizeof(sharedKeyS), false, "Shared key s");
  return 0;
}