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Need information about embedded systems

Discussion in 'Embedded' started by David, Jan 11, 2005.

  1. David

    David Guest

    I have heard that public key encryption and related cryptologies need
    32bit processors to execute at a reasonable rate. If this is not true,
    please correct me.

    Could someone recommend a cheap 32bit development board, preferably
    with an ethernet MAC (I should be able to get transceiver, magnetics,
    and connector if need be).

    Also what are the pros/cons of using a MCU with and without a MMU?
    Is programming significantly more difficult without one?

    --David
     
    David, Jan 11, 2005
    #1
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  2. David

    Robert Scott Guest

    That all depends on what you mean by reasonable. An 8-bit uP with a
    hardware multiply will do quite well. For RSA you need to multiply
    and take remainders for numbers with more that 1000 bits. That can be
    done 8 bits at a time.


    -Robert Scott
    Ypsilanti, Michigan
    (Reply through this forum, not by direct e-mail to me, as automatic reply address is fake.)
     
    Robert Scott, Jan 11, 2005
    #2
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  3. David

    David Guest

    Well I need to be able to encrypt 256 bits in less than 5 sec. or
    generate a 256 bit key with DH key exchange in the same time.
    Also any suggestions on cheap development kits

    --David
     
    David, Jan 11, 2005
    #3
  4. David

    Chris Hills Guest

    As most smart cards used to be 8 bit (8051 a lot of them) and had RSA
    you clearly don't need a 32 bit processor. Though to be fair a lot of
    them also tended to have a crypto engine on them.

    BTW define "reasonable" :)


    /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
    \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/\
    /\/\/ www.phaedsys.org \/\/
    \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
     
    Chris Hills, Jan 11, 2005
    #4
  5. Define 'reasonable'. PKE was common on 4.77MHz 8088 XT's.
    The obverse. For a stand-alone application it is easier without one.
     
    Nicholas O. Lindan, Jan 11, 2005
    #5
  6. The 32 byte memory requirement shouldn't be much of a strain.
    A 32-bit processor with an MMU may not be needed.

    As for speed, I don't think anyone makes a processor
    this slow anymore.

    Pick anything you want. If this is a 'one-of' then a
    "Basic Stamp" would work fine. Otherwise, use whatever
    you have at hand and are familiar with.
     
    Nicholas O. Lindan, Jan 11, 2005
    #6
  7. David

    David Guest

    Well the problem is: the ones I've seen range from more than my car now
    ($2000) to more than my car when I bought it a few years ago ($5000).

    Is it possible to build yourself a development kit (with a good chance
    of success) cheaply from an available MCU?
    Or buy a reasonable priced kit?

    As I said, correct me if an 8 or 16 bit MCU will do. Suggestions of
    suitable kits would be appreciated.

    Also I would prefer not having to write my own TCP/IP stack or buying
    one for $1000+. So if it is a product with a freely available TCP/IP
    stack, the happier I be.
    Also what are your thoughts on the MMU?

    --David
     
    David, Jan 11, 2005
    #7
  8. David

    David Guest

    The device will need to do the following things:

    NTP client to update RTC
    Custom server protocol for configuring device with encryption of
    communication
    Main program that will output particular data to certain peripherals
    (IR/RF encoders -> IR/RF blasters) at particular times as configured by
    client over TCP/IP through integrated ethernet.

    If all this can be smushed into one program then I guess I don't need a
    MMU or OS.
    But I don't if it will work well.

    --David
     
    David, Jan 12, 2005
    #8
  9. David

    Jezwold Guest

    A better aproach which I took when implementing a design which used AES
    as the crypto system was to design an fpga which did the bulk of the
    encryption/decryption and a smal cheapo processor to get the results on
    and off the board and handle the key scheduling.
    This saved a lot of processor time as its very easy to pipeline
    the aes algo within the fpga.
     
    Jezwold, Jan 12, 2005
    #9
  10. I implemented a *very* non-optimal "big number"
    library and DH key exchange, and was amazed at how
    long it took to execute on an MPC860.

    I also implemented DES, which didn't seem too
    heavy weight. The key exchange was by far the most
    processor intensive part of the process.

    I did this for "fun", and I really don't have any
    encryption experience other than that. Just thought
    it might be an "interesting" data point.


    --
    Michael N. Moran (h) 770 516 7918
    5009 Old Field Ct. (c) 678 521 5460
    Kennesaw, GA, USA 30144 http://mnmoran.org

    "So often times it happens, that we live our lives in chains
    and we never even know we have the key."
    The Eagles, "Already Gone"

    The Beatles were wrong: 1 & 1 & 1 is 1
     
    Michael N. Moran, Jan 12, 2005
    #10
  11. David

    Bill Knight Guest

    You might have a look at http://www.theARMPatch.com Both 32-bit,
    ~60MHz ARM eval boards there sell for about $300 USD, have 10BaseT
    ethernet, a CompactFlash connector, RTC. and come with a minimal port
    of lwIP (an open-source TCP/IP stack). There are several gcc (as well
    as reasonably low-cost commercial) distributuons available on the
    internet that are suitable for development tools

    Regards
    -Bill Knight
     
    Bill Knight, Jan 12, 2005
    #11
  12. again, what is reasonable ?
    Some implementations use FPGAs to do as much in parallel
    as possible. AFAIK, the Rhyndael/AES is available as core.

    Rene
     
    Rene Tschaggelar, Jan 12, 2005
    #12
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