FSCX_HAEN1.ino

/*  HKEX and HAEN 16 bit proof of concept code for Arduino 

    Copyright (C) 2021 Omar Alejandro Herrera Reyna

    This program is free software: you can redistribute it and/or modify
    it under the terms of the MIT License or the GNU General Public License 
    as published by the Free Software Foundation, either version 3 of the License, 
    or (at your option) any later version.
    Under the terms of the GNU General Public License, please also consider that:
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>. */

/*
FSCX Function
 */
 
//
int led = 13;
const int key_pubsize = 12; // 16 bits *3/4
const int key_privsize = 4; // 16 bits *1/4
const int int_max = 32767;
// the setup routine runs once when you press reset:
void setup() {                
  // initialize the digital pin as an output.
  pinMode(led, OUTPUT);
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }
  // prints title with ending line break 
  Serial.println("FSCX function test for Key exchange (HKEX) and encryption (HAEN)");  
}

unsigned int rol_int (unsigned int num){
  return((num << 1) | (num >> 15));
}

unsigned int ror_int (unsigned int num){
  return((num >> 1) | (num << 15));
}

unsigned int fscx_int (unsigned int a, unsigned int b){
  return (a ^ b ^ rol_int(a) ^ rol_int(b) ^ ror_int(a) ^ ror_int(b));
}

unsigned int fscx_revolve_int (unsigned int up, unsigned int down, unsigned int steps){
  unsigned int cont, result;
  result = up;
  for(cont = 0; cont<steps; cont++){
    result = fscx_int(result,down);
  }
  return(result);
}

// the loop routine runs over and over again forever:
void loop() {
  unsigned int a1,a2,b1,b2,c1,c2,d1,d2,f1,f2,m,e,p;
  
  randomSeed(analogRead(0));
  digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000); 

  a1 = (unsigned int)random(int_max);
  a2 = (unsigned int)random(int_max);
  b1 = (unsigned int)random(int_max);
  b2 = (unsigned int)random(int_max);
  m = (unsigned int)random(int_max);
  
  Serial.println(" -----------HKEX----------------");
  Serial.println("ALICE:");
  Serial.print(a1,HEX);
  Serial.println(" A1 [Alice's secret 1]");
  Serial.print(b1,HEX);
  Serial.println(" B1 [Alice's secret 2]");
  d1=fscx_revolve_int(a1,b1,key_pubsize);
  Serial.print(d1,HEX);
  Serial.println(" D1 [exchenge material = FSCX_REVOLVE_INT(A1,B1,12)");
  
  Serial.print("\t");
  Serial.println("BOB:");
  Serial.print("\t");
  Serial.print(a2,HEX);
  Serial.println(" A2 [Bob's secret 1]");
  Serial.print("\t");
  Serial.print(b2,HEX);
  Serial.println(" B2 [Bob's secret 2]");
  d2=fscx_revolve_int(a2,b2,key_pubsize);
  Serial.print("\t");
  Serial.print(d2,HEX);
  Serial.println(" D2 [exchange material = FSCX_REVOLVE_INT(A2,B2,12)");
  Serial.println("   D1-->  <--D2 [exchange]");
  
  Serial.println("ALICE:");
  f1=fscx_revolve_int(d2,b1,key_privsize) ^ a1;
  Serial.print(f1,HEX);
  Serial.println(" F1 [shared secret = FSCX_REVOLVE_INT(D2,B1,4)");
  
  Serial.print("\t");
  Serial.println("BOB:");
  f2=fscx_revolve_int(d1,b2,key_pubsize) ^ a2;
  Serial.print("\t");
  Serial.print(f1,HEX);
  Serial.println(" F2 [shared secret = FSCX_REVOLVE_INT(D1,B2,4)");
  Serial.println("   F1 == F2 [exchange]");
  
  Serial.println(" -----------HAEN----------------");
  
  Serial.println("ALICE:");
  Serial.print(m,HEX);
  Serial.println(" m [secret message in plaintext]");
  e=fscx_revolve_int(m^f1^a1,b1,key_pubsize);
  Serial.print(e,HEX);
  Serial.println(" e [encrypted message = FSCX_REVOLVE_INT(M xor F1 xor A1,B1,12)]");
  
  Serial.print("\t");
  Serial.println("BOB:");
  p=fscx_revolve_int(e,b2,key_privsize) ^ a2;
  Serial.print("\t");
  Serial.print(p,HEX);
  Serial.println(" p [decrypted message = FSCX_REVOLVE_INT(E,B2,4)");
  Serial.println("   M == P [decryption successful]");
  
  Serial.println(" ------------------------------");
  
  digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW
  delay(10000);               // wait for a few seconds
}