XXTEA encrypt / decrypt

Projects Programming
6

try this code

#define key "6b65ab3ec40de908"

uint32_t cryptKey[4];

void setup() {
  unsigned int i = 0;
  // put your setup code here, to run once:
  Serial.begin( 115200 );
  Serial.println( F("Ready") );

  Serial.println( F("the key array holds in ASCII") );
  for ( i = 0; i < 16; i += 4 ) {
    Serial.print((char) key[i]);  Serial.print(" ");
    Serial.print((char) key[i+1]);  Serial.print(" ");
    Serial.print((char) key[i+2]);  Serial.print(" ");
    Serial.println((char) key[i+3]);
  }

  Serial.println( F("the key array holds in HEX") );
  for ( i = 0; i < 16; i += 4 ) {
    Serial.print(key[i], HEX);  Serial.print(" ");
    Serial.print(key[i + 1], HEX);  Serial.print(" ");
    Serial.print(key[i + 2], HEX);  Serial.print(" ");
    Serial.println(key[i + 3], HEX);
  }  

  for ( i = 0; i < 16; ++i ) {
    ( (uint8_t*) cryptKey )[i] = key[i];
  }

  Serial.println( F("the cryptKey array bytes are") );
  for ( i = 0; i < 16; i += 4 ) {
    Serial.print(( (uint8_t*) cryptKey )[i], HEX); Serial.print(" ");
    Serial.print(( (uint8_t*) cryptKey )[i + 1], HEX); Serial.print(" ");
    Serial.print(( (uint8_t*) cryptKey )[i + 2], HEX); Serial.print(" ");
    Serial.println(( (uint8_t*) cryptKey )[i + 3], HEX);
  }

  Serial.println( F("the cryptKey array uint32_t are (HEX)") );
  for ( i = 0; i < 4; ++i ) {
    Serial.print("0x");
    Serial.println(cryptKey[i], HEX);
  }
}

void loop() {}

you will see the following output

Ready
the key array holds in ASCII
[color=red]6[/color] [color=green]b[/color] [color=blue]6[/color] [color=purple]5[/color]
a b 3 e
c 4 0 d
e 9 0 8
the key array holds in HEX
[color=red]36[/color] [color=green]62[/color] [color=blue]36[/color] [color=purple]35[/color]
61 62 33 65
63 34 30 64
65 39 30 38
the cryptKey array bytes are
[color=red]36[/color] [color=green]62[/color] [color=blue]36[/color] [color=purple]35[/color]
61 62 33 65
63 34 30 64
65 39 30 38
the cryptKey array uint32_t are (HEX)
0x[color=purple]35[/color][color=blue]36[/color][color=green]62[/color][color=red]36[/color]
0x65336261
0x64303463
0x38303965

Note the little endian versus big endian.

Most significant byte in cryptKey is the 4th byte as the AVR processor is little endian

if you used Javascript code to test in a browser, you are CPU architecture dependant and possibly big endian.

I guess my question is: what key did you use to generate the encoding to get the expected output? is that key the same within your arduino given endianness