Re: Security for embedded device

From: Francois Grieu (fgrieu_at_francenet.fr)
Date: 06/30/04 

Date: Wed, 30 Jun 2004 08:58:01 +0200

"Joris Dobbelsteen" wrote:

> about 25100 / 8 = ~3150 cycles/byte
>
> Obviously the code is open for optimizations, as already suggested
> in the paper.

My experience is that embedded C compilers for 8-bit CPUs (6805,
8051, ST7..) generate uglly code for the shift operations used
by TEA. All but the most naive assembly language implementation
should be better, by a big factor.

> Also reducing the number of rounds to ~16 will come very close
> to my 1K cycles request.

Don't do this !

   Francois Grieu

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