CC1110 AES unit

Hi.

There is also AES code to be found here:
https://community.ti.com/forums/p/561/1336.aspx#1336

It's for the 802.15.4 devices, but the source code for the CC2430 could be used for CC1110 when it comes to AES as the engine is the same in those two devices.

Hi,

Thanks found the problem, there needs to be a delay between the uploading and downloading and then RDY flag then goes active.

Cheers,

Charles

Hi Charles,

I have had a problem similar to yours. I have added a delay, but the result I get from the coprocessor after decryption is all FF's. Also if I do decryption the result is again all FF's.

What is your experience?

Cheers

Hi Rajo,

Although the delay in swra209, link above, was only 1us I used a 40us delay as I had a function for another interface and I was not pressed for time.

void InitEnc (void)
{
int i;

    // Download Key (Set ENCCS.CMD = 10b),
    // and start corresponding AES process (ENCCS.ST = 1)
    ENCCS = ENCCS_MODE_ECB | ENCCS_CMD_LOAD_KEY | ENCCS_ST;
    for (i = 0; i < SIZE_OF_AES_BLOCK; i++) {
        ENCDI = EncKey[i];
    }

    // Monitor AES (ENCCS.RDY) to wait until key downloaded
    while(!(ENCCS & ENCCS_RDY));

    // Generate IV/NONCE:
    // Not used as using ECB mode, so set IV/NONCE to 0

    // Dwonload IV/NONCE (Set ENCCS.CMD = 11b)
    // and start corresponding AES process (ENCCS.ST = 1)
    ENCCS = ENCCS_MODE_ECB | ENCCS_CMD_LOAD_IV | ENCCS_ST;
    for (i = 0; i < SIZE_OF_AES_BLOCK; i++) {
        ENCDI = 0;
    }

    // Monitor AES (ENCCS.RDY) to wait until IV/NONCE downloaded
    while(!(ENCCS & ENCCS_RDY));
}

void aes_encrypt(unsigned char *data)
{
int i;

    // Perform AES encryption/decryption on allocated AES buffer ("*data"):

    // Configure and start AES coprocessor for the desired AES mode:
    // Encryption => ENCCS.CMD = 00b, decryption mode => ENCCS.CMD = 01b.
    // Use so-called Cipher Block Chaining encryption mode => ENCCS.MODE = 000b.
    // Start AES processing (ENCCS.ST = 1) of source buffer (*data).
    // Only valid for encryption mode !
    ENCCS = ENCCS_MODE_ECB | ENCCS_CMD_ENC | ENCCS_ST;
    // Download data block (16 bytes) to AES coprocessor:
    for (i = 0; i < SIZE_OF_AES_BLOCK; i++) {
        ENCDI = data[i];
    }

    Wait_4_40us();  // Give the AES time to do it's thing

    // Upload data block (16 bytes) to allocated AES buffer:
    for (i = 0; i < SIZE_OF_AES_BLOCK; i++) {
        data[i] = ENCDO;
    }

    // Monitor AES (ENCCS.RDY) to wait until data block downloaded
    while(!(ENCCS & ENCCS_RDY));

}

Hope this helps.

Cheers,

Charles

I thought my experience would be useful for some future readers, so here it comes. Basically, my problem had to do with declaration of the AES input and output strings. Once I had them declared ordinarily, i.e.

BYTE  aes_input[SIZE_OF_ENC_BUFFER]; // Source buffer
BYTE  aes_output[SIZE_OF_ENC_BUFFER]; // Target buffer

everything started to work fine.

The declaration from the app note:

__no_init BYTE __xdata aes_buffer_1[SIZE_OF_ENC_BUFFER];

__no_init BYTE __xdata aes_buffer_2[SIZE_OF_ENC_BUFFER]; 

did not work for me.

I have used IAREW8051 7.20H

Cheers

Hi there,

The AES Design Note (DN108) has now been updated to incorporate delay between AES download (ENCDI write) and AES upload (ENCDO read), ref.:

[DN108 - Using AES Encryption in CC111xFx]
http://www.ti.com/litv/pdf/swra172b

Cheers,
RF4ALL

Hi RF4ALL,

Your link above is invalid, can you correct it plesae. I have searched for the document and could not find it.

Cheers,

Charles

Hi Charles,

We are looking into this.  It's actually not an issue with the link but how the document appears on the web.  Stay tuned!

Regards,

nancy!

Hi Spachner -- I will have an answer for you by tomorrow.  Thanks for checking-in!

Nancy

Ok, I lied, it's after tomorrow.  However, the team will have this document available in a week or so.  Please send me a private message so I can provide you with more details.

Hi Nancy;

Currently I am working with CC430F6137.

would you pls provide me the link for example of AES.

It will be great help from TI

.Thanks