Re: RC5 with FPGAs

Are they available? All I see are fancy claims on their website.
--
Martin

On Fri, September 8, 2006 5:57 pm, Olivier Meyer wrote:
> I am currently interested in Achronix Semiconductor's FPGAs, which can
> operate at 2 GHz
>
> On 9/8/06, Olivier Meyer <[email protected]> wrote:
>
>>
>> What about the partial matches: how would one do that in an FPGA?
>>
>>
>>
>> On 9/7/06, david fleischer <cilantro_il-/[email protected] > wrote:
>>
>>>
>>> That's interesting.
>>> How does byte-reversed increment work?
>>>
>>>
>>> You suggest doing 6 rounds instead of 3. This to avoid
>>> the penalty of storing the array until the key is tested. But the RC5
>>> algorithm is separated into stages. You need all the data for the last
>>> step, so you need at least to have gone through 2 rounds when starting
>>> to encrypt the words. How does the pyramid work?
>>>
>>>
>>> David
>>>
>>>
>>> --- Dan Oetting <dan_oetting-r9/[email protected]> wrote:
>>>
>>>
>>>>
>>>> On Sep 6, 2006, at 12:07 PM, david fleischer wrote:
>>>>
>>>>
>>>>> By the way, I'm not sure pipelining will bring you
>>>>> great benefits in an FPGA. A back of the laptop calculation tells
>>>>> me that you'll need
>>>> approximately
>>>>> 1Kbit of memory per key. This may mean that most
>>>>>
>>>> of
>>>>> the archirecture will be shoveling data back and
>>>> forth
>>>>> to the core.
>>>>
>>>> You don't have to store the data. You can recompute
>>>> it. Instead of 3 rounds with intermediate data stored between rounds
>>>> you implement 6 rounds in a pyramid so the correct data is provided
>>>> to each stage as it's needed..
>>>>
>>>>> I also have a question, can someone help me figure
>>>>>
>>>> out
>>>>> the code in the source ANSI cores? I cannot
>>>> understand
>>>>> how the key increment is done. (that is to say, I
>>>> see
>>>>> what the code is doing, but I cannot figure out
>>>> why
>>>>> this does any good.)
>>>>
>>>> What the code is doing is incrementing the key in
>>>> byte reversed order. Why this is done is because the calculations in
>>>> the first 2 1/2 iterations of the first round then become
>>>> constants so the loop can run a few keys per second faster. It won't
>>>> help your hardware unless your design is fully pipelined so you can
>>>> consolidate the first few sets of gates in each pipe. But you still
>>>> need to implement the byte reversed increment to be compatible with
>>>> the d.net project.
>>>>
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>>>
>>>>
>>>
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>>
>>
>>
>> --
>> -----------------------
>> Olivier V. Meyer
>> Congress shall make no law respecting an establishment of religion, or
>> prohibiting the free exercise thereof; or abridging the freedom of
>> speech, or of the press; or the right of the people peaceably to
>> assemble, and to petition the government for a redress of grievances.
>>
>
>
>
> --
> -----------------------
> Olivier V. Meyer
> Congress shall make no law respecting an establishment of religion, or
> prohibiting the free exercise thereof; or abridging the freedom of speech,
>  or of the press; or the right of the people peaceably to assemble, and
> to petition the government for a redress of grievances.
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