0

I'm trying to implement an AES encryption function on my ESP8266 controller, using Arduino ide and this aes library. I finally made it work after many attempts but the output i get from the encryption function is only numerical and it doesn't correspond to other encryptions made by other softwares.

This is the code part relative to the AES encryption:

 #include <AES.h>

AES aes ;
byte *key = (unsigned char*)"0123456789010123";
unsigned long long int my_iv = 36753562;
 tempToken = RANDOM_REG32 % 10000;
    randomstr = String(tempToken);
    //answer = "{\"token\":\"" + randomstr + "\"}";
    byte plain[4];
    randomstr.getBytes(plain, 4);
    Serial.println(randomstr);
    Serial.println(plain[0]);
    Serial.println(plain[1]);
    Serial.println(plain[2]);
    Serial.println(plain[3]);
    byte cipher [48];
  //  aes.iv_inc();
    byte iv [N_BLOCK] ;
    aes.set_IV(my_iv);
    aes.do_aes_encrypt(plain, 48, cipher, key, 128, iv);
    String ciphertoken = "";
    for (int i = 0; i < 48; i++) {
      ciphertoken += cipher[i];
    }
    answer = "{\"token\":\"" + ciphertoken + "\"}";

It basically generates a random number between 0 - 9999, then converts it in a byte array (because aes function needs a byte array as input), then encrypt this byte array and prints the output, written in cipher byte array.

This is the output I get from it

6188
54
49
56
0
{"token":"521111513725521540120674957151112223103194250224197251261938514437131212302201813929189123134524113912554682501508415421130220"}

I can't understand if I did something wrong of if it is formatted in a strange way and if I can get the right encryption from it

closed as off-topic by jfpoilpret, Dat Ha, rebatoma, KIIV, uint128_t Dec 29 '16 at 17:31

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "This question does not appear to be about Arduino, within the scope defined in the help center." – jfpoilpret, Dat Ha, rebatoma, KIIV, uint128_t
If this question can be reworded to fit the rules in the help center, please edit the question.

  • 1
    Could you replace your code with a minimal, complete and verifiable example (stackoverflow.com/help/mcve) please (remove the random part - use a well-defined input for this purpose), as well as the output you expect? – Mark Smith Dec 13 '16 at 19:12
0

I don't know whether this is the only problem, but the way you are building up the string is bad: you are appending the decimal value of each byte of the cipher - so if your cipher array were, say, { 0x52, 0x11, 0x115, 0x137, 0x255, 0x215, 0x40, 0x1, 0x20 .... } you'd get the string you're getting: 521111513725521540120... That's probably not what you want.

Probably what you want for that part is to base64-encode cipher, which you can find out how to do, for example, here. (If you see encrypted stuff in printable format, usually it's base64 encoded.)

Not the answer you're looking for? Browse other questions tagged or ask your own question.