Crypo

[ZiGaMi]

CMOX: https://www.st.com/en/embedded-software/x-cube-cryptolib.html

With python tool: https://pycryptodome.readthedocs.io/en/latest/src/cipher/aes.html

You can use AES 128bit key CBC mode

[ZiGaMi]

Python script used for AES-CTR cryption:

import os
import binascii
from Crypto.Cipher import AES
from Crypto.Random import get_random_bytes

from Crypto.Util import Counter

def print_debug(plain, encode, decode):

    print("---------------------------------------------------------------")
    print("  Plain: %s" % plain)
    print("Encoded: %s" % encode)
    print("         %s" % "".join( "\\x%02X" % b for b in encode ))
    print("Decoded: %s" % decode)
    print("         %s" % "".join( "\\x%02X" % b for b in decode ))
    print("---------------------------------------------------------------")
    print("")

def int_of_string(s):
    return int(binascii.hexlify(s), 16)

def aes_encode(plain_data):

    # AES Key and IV
    key = b"\x2b\x7e\x15\x16\x28\xae\xd2\xa6\xab\xf7\x15\x88\x09\xcf\x4f\x3c"
    iv = b"\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"

    # Create cipher
    ctr = Counter.new(128, initial_value=int_of_string(iv))
    cipher = AES.new(key, AES.MODE_CTR, counter=ctr)

    # Encode
    return list(cipher.encrypt( bytearray( plain_data )))

def aes_decode(cipher_data):

    # AES Key and IV
    key = b"\x2b\x7e\x15\x16\x28\xae\xd2\xa6\xab\xf7\x15\x88\x09\xcf\x4f\x3c"
    iv = b"\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"

    # Create cipher
    ctr = Counter.new(128, initial_value=int_of_string(iv))
    _cipher = AES.new(key, AES.MODE_CTR, counter=ctr)

    # Decrypt
    return list(_cipher.decrypt( bytearray( cipher_data )))

if __name__ == "__main__":

    # Init AES engine
    #cipher = AES.new(key, AES.MODE_CBC, iv)

    # =================================================================

    # Plain data
    plain_data = [ 0x00 ]

    # Encode
    encode_data = aes_encode(plain_data)

    # Decode data
    decode_data = aes_decode(encode_data)

    # Show results
    print_debug( plain_data, encode_data, decode_data )
    # =================================================================

    # Plain data
    plain_data = [ 0x00 ]

    # Encode
    encode_data = aes_encode(plain_data)

    # Decode data
    decode_data = aes_decode(encode_data)

    # Show results
    print_debug( plain_data, encode_data, decode_data )

    # =================================================================

    # Plain data
    plain_data = [ 0x00, 0x01, 0x02, 0x03 ]

    # Encode
    encode_data = aes_encode(plain_data)

    # Decode data
    decode_data = aes_decode(encode_data)

    # Show results
    print_debug( plain_data, encode_data, decode_data )
    # =================================================================

    # Plain data
    plain_data = [ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F ]

    # Encode
    encode_data = aes_encode(plain_data)

    # Decode data
    decode_data = aes_decode(encode_data)

    # Show results
    print_debug( plain_data, encode_data, decode_data )
    # =================================================================

    # Plain data
    plain_data = [ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0xAA, 0xBB ]

    # Encode
    encode_data = aes_encode(plain_data)

    # Decode data
    decode_data = aes_decode(encode_data)

    # Show results
    print_debug( plain_data, encode_data, decode_data )
    # =================================================================

With a combination of C code, using ST CMOX lib:

/* Initialize cryptographic library */
if ( cmox_initialize(NULL) != CMOX_INIT_SUCCESS )
{
PROJ_CFG_ASSERT( 0 );
}

static bool encode(const uint8_t * const p_plain, const uint32_t plain_size, uint8_t * const p_crypt, uint32_t * const p_crypt_size)
{
    uint32_t rtn_status = cmox_cipher_encrypt( CMOX_AES_CTR_ENC_ALGO, (uint8_t*) p_plain, plain_size, Key, sizeof(Key), IV, sizeof(IV), (uint8_t*) p_crypt, (size_t*) p_crypt_size );

    if ( CMOX_CIPHER_SUCCESS == rtn_status )
    {
        return true;
    }
    else
    {
        return false;
    }
}

static bool decode(const uint8_t * const p_crypt, const uint32_t crypt_size, uint8_t * const p_plain, uint32_t * const p_plain_size)
{
    uint32_t rtn_status = cmox_cipher_decrypt( CMOX_AES_CTR_DEC_ALGO, (uint8_t*) p_crypt, crypt_size, Key, sizeof(Key), IV, sizeof(IV), (uint8_t*) p_plain, (size_t*) p_plain_size );

    if ( CMOX_CIPHER_SUCCESS == rtn_status )
    {
        return true;
    }
    else
    {
        return false;
    }
}

[ZiGaMi]

DONE