/**
 * Spritz Cipher Hash Test
 *
 * This example code test SpritzCipher library hash 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>


/* Data to input */
const byte testData1[3] = { 'A', 'B', 'C' };
const byte testData2[4] = { 's', 'p', 'a', 'm' };
const byte testData3[7] = { 'a', 'r', 'c', 'f', 'o', 'u', 'r' };

/* Test vectors */
/* Data 'ABC' hash test vectors */
const byte testVector1[32] =
{ 0x02, 0x8f, 0xa2, 0xb4, 0x8b, 0x93, 0x4a, 0x18,
  0x62, 0xb8, 0x69, 0x10, 0x51, 0x3a, 0x47, 0x67,
  0x7c, 0x1c, 0x2d, 0x95, 0xec, 0x3e, 0x75, 0x70,
  0x78, 0x6f, 0x1c, 0x32, 0x8b, 0xbd, 0x4a, 0x47
};
/* Data 'spam' hash test vectors */
const byte testVector2[32] =
{ 0xac, 0xbb, 0xa0, 0x81, 0x3f, 0x30, 0x0d, 0x3a,
  0x30, 0x41, 0x0d, 0x14, 0x65, 0x74, 0x21, 0xc1,
  0x5b, 0x55, 0xe3, 0xa1, 0x4e, 0x32, 0x36, 0xb0,
  0x39, 0x89, 0xe7, 0x97, 0xc7, 0xaf, 0x47, 0x89
};
/* Data 'arcfour' hash test vectors */
const byte testVector3[32] =
{ 0xff, 0x8c, 0xf2, 0x68, 0x09, 0x4c, 0x87, 0xb9,
  0x5f, 0x74, 0xce, 0x6f, 0xee, 0x9d, 0x30, 0x03,
  0xa5, 0xf9, 0xfe, 0x69, 0x44, 0x65, 0x3c, 0xd5,
  0x0e, 0x66, 0xbf, 0x18, 0x9c, 0x63, 0xf6, 0x99
};


void testFunc(const byte ExpectedOutput[32], const byte *data, byte dataLen)
{
  byte hashLen = 32; /* 256-bit */
  byte digest[hashLen]; /* Output buffer */
  byte digest_2[hashLen]; /* Output buffer for chunk by chunk API */
  spritz_ctx hash_ctx; /* the CTX for chunk by chunk API */
  unsigned int i;

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

  spritz_hash_setup(&hash_ctx);
  /* For easy test: code add a byte each time */
  for (i = 0; i < dataLen; i++) {
    spritz_hash_update(&hash_ctx, data + i, 1);
  }
  spritz_hash_final(&hash_ctx, digest_2, hashLen);

  spritz_hash(digest, hashLen, data, dataLen);

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

  /* Check the output */
  if (spritz_compare(digest, ExpectedOutput, sizeof(digest)) || spritz_compare(digest_2, ExpectedOutput, sizeof(digest_2))) {
    /* 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_hash*() test]\n");

  /* Data: ABC */
  testFunc(testVector1, testData1, sizeof(testData1));
  /* Data: spam */
  testFunc(testVector2, testData2, sizeof(testData2));
  /* Data: arcfour */
  testFunc(testVector3, testData3, sizeof(testData3));

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