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    bcd32 with 128bit seed - question on predicting the output


    Just a quick note on a change of the seeding function for bcd32. It
    accept a 128bit seed now in order to set the initial state of a,b,c,d
    and t. This way for example a 128bit hash can be used for seeding.
    The seed function include a check that a and b never be set to zero.

    The modified source code for keystream generation is available here

    http://www.freecx.co.uk/bcd32/bcd32_keystream.c

    debian Pastezone

    Additionally I like to ask if someone has any idea on how to predict the
    output of bcd32 without knowing the 128bit seed nor the internal state?



    P.S.: Test tools as well as the very first version over here
    Index of /bcd32
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    Additionally I like to ask if someone has any idea on how to predict the
    output of bcd32 without knowing the 128bit seed nor the internal state?
    Well, for a start this is a possible way:

    We capture two or more consecutive output values, seed the PRNG with
    arbitrary 128bit values and observe the output and all internal values
    until at least two identical consecutive output values were found. At
    this moment we know the complete internal state and can calculate all
    future states.

    But this is a very expensive approach. Is anyone aware of a more
    effective and faster method?

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