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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, Jan 11, 2005
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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
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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, Jan 11, 2005
  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
  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
  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
  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, Jan 11, 2005
  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
    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, Jan 12, 2005
  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
  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
  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

    -Bill Knight
    Bill Knight, Jan 12, 2005
  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 Tschaggelar, Jan 12, 2005
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