/**
 * Spritz Cipher Stream Test
 *
 * This example code test SpritzCipher library stream (PRNG) output
 * using test vectors from Spritz paper "RS14.pdf" Page 30:
 * <https://people.csail.mit.edu/rivest/pubs/RS14.pdf>
 *
 * The circuit:  No external hardware needed.
 *
 * by Abderraouf Adjal.
 *
 * This example code is in the public domain.
 */

/* ArduinoSpritzCipher documentation: <README.md> */


/* ArduinoSpritzCipher is configurable in <SpritzCipher.h> with:
 * SPRITZ_TIMING_SAFE_CRUSH, SPRITZ_WIPE_TRACES, SPRITZ_WIPE_TRACES_PARANOID,
 * SPRITZ_USE_LIBC.
 * For detailed information, read the documentation.
 */
#include <SpritzCipher.h>


/* Keys to input */
const byte testKey1[3] = { 'A', 'B', 'C' };
const byte testKey2[4] = { 's', 'p', 'a', 'm' };
const byte testKey3[7] = { 'a', 'r', 'c', 'f', 'o', 'u', 'r' };

/* Test vectors */
/* Key 'ABC' stream test vectors */
const byte testVector1[32] =
{ 0x77, 0x9a, 0x8e, 0x01, 0xf9, 0xe9, 0xcb, 0xc0,
  0x7f, 0xb9, 0x6b, 0x7e, 0xc1, 0x93, 0x6e, 0x24,
  0x2e, 0x54, 0xf1, 0x8b, 0x6c, 0x3c, 0x76, 0xcf,
  0x8f, 0xc8, 0x2f, 0x22, 0x2b, 0x20, 0xe4, 0xbb
};
/* Key 'spam' stream test vectors */
const byte testVector2[32] =
{ 0xf0, 0x60, 0x9a, 0x1d, 0xf1, 0x43, 0xce, 0xbf,
  0x58, 0xdc, 0xff, 0x3d, 0x30, 0xb7, 0xc2, 0x59,
  0x9d, 0x2f, 0xb0, 0xdc, 0x2b, 0x7a, 0x12, 0xc4,
  0xe8, 0x92, 0x16, 0xcc, 0x5d, 0xe9, 0x29, 0x67
};
/* Key 'arcfour' stream test vectors */
const byte testVector3[32] =
{ 0x1a, 0xfa, 0x8b, 0x5e, 0xe3, 0x37, 0xdb, 0xc7,
  0x22, 0x59, 0x7f, 0x0f, 0xdc, 0x3a, 0x42, 0xc7,
  0x75, 0x4b, 0xf1, 0x03, 0x6f, 0x54, 0xfb, 0x4a,
  0xeb, 0x03, 0x35, 0xd4, 0xa4, 0xe9, 0xa3, 0x6e
};


void testFunc(const byte ExpectedOutput[32], const byte *data, byte dataLen)
{
  byte buf[32]; /* Output buffer */
  spritz_ctx s_ctx;
  unsigned int i;

  /* Print key */
  for (i = 0; i < dataLen; i++) {
    Serial.write(data[i]);
  }
  Serial.println();

  spritz_setup(&s_ctx, data, dataLen);

  for (i = 0; i < sizeof(buf); i++) {
    buf[i] = spritz_random8(&s_ctx);
    if (buf[i] < 0x10) { /* To print "0F" not "F" */
      Serial.write('0');
    }
    Serial.print(buf[i], HEX);
  }

  /* Check the output */
  if (spritz_compare(buf, ExpectedOutput, sizeof(buf))) {
    /* If the output is wrong "Alert" */
    digitalWrite(LED_BUILTIN, HIGH); /* Turn pin LED_BUILTIN On (Most boards have this LED connected to digital pin 13) */
    Serial.println("\n** WARNING: Output != Test_Vector **");
  }
  Serial.println();
}

void setup() {
  /* Initialize serial and wait for port to open */
  Serial.begin(9600);
  while (!Serial) {
    ; /* Wait for serial port to connect. Needed for Leonardo only */
  }

  /* initialize digital pin LED_BUILTIN (Most boards have this LED connected to digital pin 13) as an output */
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, LOW);
}

void loop() {
  Serial.println("[Spritz spritz_random8() test]\n");

  /* Key: ABC */
  testFunc(testVector1, testKey1, sizeof(testKey1));
  /* Key: spam */
  testFunc(testVector2, testKey2, sizeof(testKey2));
  /* Key: arcfour */
  testFunc(testVector3, testKey3, sizeof(testKey3));

  delay(5000); /* Wait 5s */
  Serial.println();
}