RSA Decryption Failure (-147) while sending and receiving data from Modem on UART

[Usama Shafiq]

Hi there. I have been working on a small project where I am using an encryption library for communication over ble. I am receiving encrypted token over ble charcteristics. Then i use Crypto libraries to decrypt the token and perform modem function on UART. While communicating over UART with modem i send and receive data from modem.. when I receive consecutive tokens on BLE, initially MCU is able to decrypt the tokens. but after 5-6 tokens it start failing to decrypt the exact same token. When I disable uart tx then this issue does not come... or may be it is delay enough..
I need help in this. I am not able to understand what causes the failure in decryption.

[Sigurd]

Hi!

I am using an encryption library for communication over ble.

What encryption library are you using? 

[Usama Shafiq]

MbedTLS

[Sigurd]

And you are getting a RSA Decryption Failure (-147) returned from a function? What function are you using ?

[Usama Shafiq]

psa_status_t status;

int out_size = 0;

status = psa_asymmetric_decrypt(m_locker_rsa_keypair_handle,

                  PSA_ALG_RSA_PKCS1V15_CRYPT,

                  m_rsa_enc_key,

                  t_ble_rsa_header_size, NULL, 0,

                  m_aes_key,

                 AES_KEY_SIZE, &out_size);

if (status != PSA_SUCCESS)

{

         sb_print_log(LOG_DEBUG," --->decrypt_message_rsa failed! (Error: %d)", status);

         return status;

}

this is giving -147

which is :

/** A hardware failure was detected.

*

* A hardware failure may be transient or permanent depending on the

* cause. */

#define PSA_ERROR_HARDWARE_FAILURE ((psa_status_t)-147)

[Usama Shafiq]

The issue has been resolved. It was a memory leak in the UART callback which was affecting the buffers that are being used in decryption.