TMS320F28069: Questions about suitability for AES authenticated cryptography and firmware update

JP Norair

Part Number: TMS320F28069
Other Parts Discussed in Thread: AES-128

I'm in the position where I need to make a connected device out of a C2000, which seems to me like an architecture that is not intended to be a connected device.

I need to do the following things:

Source or implement an authenticated cipher using AES-128. I have an EAX implementation that works exceptionally well on normal CPUs, but ciphering and sbox computations get hobbled by the 16 bit byte on C2000. EAX is great because it has a small codebase, but I'd be will to consider OCB or GCM if need be. CCM as a last resort.
Source or implement some sort of ultra-minimalist file system on C2000. I need a way to assign privileges to data elements such that certain keys have different access to files. Again, I have an implementation that works exceptionally well on normal CPUs, but it gets hobbled by the 16 bit byte.

I'm open to all manners of solutions.

Alternatively, perhaps someone at TI (or from the internet in general) can recommend an ARM CM3/CM4 part that has similar peripherals as the C2000. That would be another option.

over 7 years ago

0 Sal Pezzino over 7 years ago

TI__Mastermind 32995 points

Hi JP,

Please see the code located here: http://www.ti.com/tool/AES-128

To get it working for C2000, you only need to modify 2 lines of code.

Use this function for galois_mul2()

// multiply by 2 in the galois field
unsigned char galois_mul2(unsigned char value)
{
if (value>>7)
{
return (((value << 1)^0x1b) & 0xFF);
} else
return ((value << 1) & 0xFF);
}

Hope this helps.

Let us know if you have any other questions.

Regards,
sal

0 Sal Pezzino over 7 years ago in reply to Sal Pezzino

TI__Mastermind 32995 points

If you need more performance, there are solutions on the interweb which are optimized for performance, but not memory. They use 5 256x32-bit arrays each for encryption and decryption. The computational time is significantly decreased and would help if you need the performance. That is, they use 5 256x32-bit tables for encryption and another 5 256x32-bit tables for decryption.

Hope this helps.

sal

0 JP Norair over 7 years ago in reply to Sal Pezzino

Intellectual 630 points

Is there a cipher library to go with this, or not? AES (or any cryptography) without ciphering and authentication is weak. Nonetheless, thanks for the link -- at least we can check-off the AES component!

0 Sal Pezzino over 7 years ago in reply to JP Norair

TI__Mastermind 32995 points

JP,

Unfortunately, we do not have any such library at this point.

Regards,
sal

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TMS320F28069: Questions about suitability for AES authenticated cryptography and firmware update