Cannot generate correct cipher

[klack]

I have been trying to use this library but cannot get the same result as my python code. They use the same IV and Key.

Arduino Code:

#include <AESLib.h>
AESLib aesLib;

byte aes_key[] = { 0x06,0xa9,0x21,0x40,0x36,0xb8,0xa1,0x5b,0x51,0x2e,0x03,0xd5,0x34,0x12,0x00,0x06 };

char cleartext[256];
char ciphertext[512];

String encrypt(char * msg, byte iv[]) {
  int msgLen = strlen(msg);
  char encrypted[2 * msgLen];
  aesLib.encrypt64(msg, msgLen, encrypted, aes_key, sizeof(aes_key), iv);
  return String(encrypted);
}

void setup() {
  Serial.begin(9600);
}

void loop() {
  sprintf(cleartext, "Single block msg");

  aesLib.set_paddingmode(paddingMode::ZeroLength);

  // Encrypt Data
  byte enc_iv[N_BLOCK] = { 0x3d,0xaf,0xba,0x42,0x9d,0x9e,0xb4,0x30,0xb4,0x22,0xda,0x80,0x2c,0x9f,0xac,0x41 };
  String encrypted = encrypt(cleartext, enc_iv);
  sprintf(ciphertext, "%s", encrypted.c_str());
  Serial.print("Base64 encoded Ciphertext: ");
  Serial.println(encrypted);
}

Output: Base64 encoded Ciphertext: D9lURiJvj46w14X/1dYlEWf3tkHEaNrfgBrV733sCcQ=

Python:

import base64
from Cryptodome.Cipher import AES
from Cryptodome.Util.Padding import pad

str = "Single block msg"
print(f"Input string: {str}")
print(f"String length: {len(str)}")
key = bytearray.fromhex('06a9214036b8a15b512e03d534120006')
print(f"Key length: {len(key)}")
iv = bytearray.fromhex('3dafba429d9eb430b422da802c9fac41')
print(f"IV length: {len(iv)}")
cipher = AES.new(key, AES.MODE_CBC, iv)
ct_bytes = cipher.encrypt(str.encode())
print(f"Cipher: {ct_bytes.hex()}")
base64_bytes = base64.b64encode(ct_bytes)
print(f"Base64: {base64_bytes.decode()}")

Output: Base64: 41N3nBB5rrgnCJQtvncYGg==

[suculent]

How do you set padding in Python? It seems to have no padding whatsoever (given the length of resulting base64 data).

Try to change aesLib.set_paddingmode(paddingMode::ZeroLength); to aesLib.set_paddingmode(paddingMode::CMS);

It seems the ZeroLength padding is something else than what does the default Cryptodome AES use.

Also, don't use the encrypt64 and decrypt64 methods, those should apparently have been already deprecated.

[klack]

Hey suclent. Thanks for the reply. I am not setting any padding at the moment, however if there was padding, the first bytes would be the same: 41N3nBB5rrgnCJQtvncYGg==

[klack]

I am using the test vectors, case 1 published here:

https://tools.ietf.org/html/rfc3602#page-6

[suculent]

I guess you should not use deprecated encrypt64 function.

[klack]

I am using your provided example in the examples directory. I don't have time to go back and try it again, so I will close this.