Solved
Using AES-GCM encryption and the results of ciphertext and tag are incorrect.
Hello,
I am trying to use AES-GCM from the STM32 cryptographic library V4.2.0 to encrypt data.
When running the example program, encryption and decryption work smoothly.
However, when I integrate the library and function into my existing program, the encrypted ciphertext differs from expected_ciphertext.
Additionally, using this incorrect ciphertext and incorrect tag still decrypts to the correct plaintext.
Could you please advise where the error might be causing this result?
const uint8_t Key[] =
{
0x46, 0x3b, 0x41, 0x29, 0x11, 0x76, 0x7d, 0x57, 0xa0, 0xb3, 0x39, 0x69, 0xe6, 0x74, 0xff, 0xe7,
0x84, 0x5d, 0x31, 0x3b, 0x88, 0xc6, 0xfe, 0x31, 0x2f, 0x3d, 0x72, 0x4b, 0xe6, 0x8e, 0x1f, 0xca
};
const uint8_t IV[] =
{
0x61, 0x1c, 0xe6, 0xf9, 0xa6, 0x88, 0x07, 0x50, 0xde, 0x7d, 0xa6, 0xcb
};
const uint8_t Plaintext[] =
{
0xe7, 0xd1, 0xdc, 0xf6, 0x68, 0xe2, 0x87, 0x68, 0x61, 0x94, 0x0e, 0x01, 0x2f, 0xe5, 0x2a, 0x98,
0xda, 0xcb, 0xd7, 0x8a, 0xb6, 0x3c, 0x08, 0x84, 0x2c, 0xc9, 0x80, 0x1e, 0xa5, 0x81, 0x68, 0x2a,
0xd5, 0x4a, 0xf0, 0xc3, 0x4d, 0x0d, 0x7f, 0x6f, 0x59, 0xe8, 0xee, 0x0b, 0xf4, 0x90, 0x0e, 0x0f,
0xd8, 0x50, 0x42
};
const uint8_t AddData[] =
{
0x0a, 0x68, 0x2f, 0xbc, 0x61, 0x92, 0xe1, 0xb4, 0x7a, 0x5e, 0x08, 0x68, 0x78, 0x7f, 0xfd, 0xaf,
0xe5, 0xa5, 0x0c, 0xea, 0xd3, 0x57, 0x58, 0x49, 0x99, 0x0c, 0xdd, 0x2e, 0xa9, 0xb3, 0x59, 0x77,
0x49, 0x40, 0x3e, 0xfb, 0x4a, 0x56, 0x68, 0x4f, 0x0c, 0x6b, 0xde, 0x35, 0x2d, 0x4a, 0xee, 0xc5
};
const uint8_t Expected_Ciphertext[] =
{
0x88, 0x86, 0xe1, 0x96, 0x01, 0x0c, 0xb3, 0x84, 0x9d, 0x9c, 0x1a, 0x18, 0x2a, 0xbe, 0x1e, 0xea,
0xb0, 0xa5, 0xf3, 0xca, 0x42, 0x3c, 0x36, 0x69, 0xa4, 0xa8, 0x70, 0x3c, 0x0f, 0x14, 0x6e, 0x8e,
0x95, 0x6f, 0xb1, 0x22, 0xe0, 0xd7, 0x21, 0xb8, 0x69, 0xd2, 0xb6, 0xfc, 0xd4, 0x21, 0x6d, 0x7d,
0x4d, 0x37, 0x58,
};
const uint8_t Expected_Tag[] =
{
0x24, 0x69, 0xce, 0xcd, 0x70, 0xfd, 0x98, 0xfe, 0xc9, 0x26, 0x4f, 0x71, 0xdf, 0x1a, 0xee, 0x9a
};incorrect_ciphertext:
{
0xA3, 0x0A, 0x42, 0x8A, 0xCA, 0x35, 0x1C, 0x9A, 0x40, 0x45, 0x06, 0xF0, 0xA1, 0xB9, 0x29, 0x6C,
0x20, 0xE8, 0x43, 0x35, 0x4D, 0xF2, 0xFD, 0x12, 0x98, 0x5E, 0xE3, 0x22, 0xC0, 0xF6, 0xD8, 0xEF,
0x47, 0x17, 0x6C, 0x36, 0xC7, 0x09, 0x4D, 0x3B, 0xCE, 0xC0, 0xAD, 0xC0, 0xB9, 0xD2, 0x06, 0xC3,
0x6D, 0x4F, 0x8C,
}
incorrect_tag:
{
0x8D, 0xF4, 0x2D, 0x51, 0x9A, 0x60, 0x48, 0xD6, 0x9C, 0x93, 0xD7, 0xA3, 0xF1, 0x84, 0xAA, 0xB4,
}retval = cmox_aead_encrypt(CMOX_AES_GCM_ENC_ALGO, /* Use AES GCM algorithm */
Plaintext, sizeof(Plaintext), /* Plaintext to encrypt */
sizeof(Expected_Tag), /* Authentication tag size */
Key, sizeof(Key), /* AES key to use */
IV, sizeof(IV), /* Initialization vector */
AddData, sizeof(AddData), /* Additional authenticated data */
Computed_Ciphertext, &computed_size); /* Data buffer to receive generated ciphertext
and authentication tag */
The model used in the example program is NUCLEO-L476RG.
My development board model is STM32L431CBT6.
Using KEIL5.