Re: Java encryption implementation

From: TC (aatcbbtccctc_at_yahoo.com)
Date: 11/29/05

  • Next message: Joseph Ashwood: "Re: Looking for an encryption program" 
    Date: 29 Nov 2005 00:21:20 -0800

    Hi Lars

    I'm not an expert in crypography, but I do know what the others are
    getting at here.

    There are several aspects of "random numbers" that are important in
    cryptography. One of these is randomness. (If the generator produces
    highly non-random results, this could help an attacker to crack it.)
    But another one is /unpredictability/ - a completely different thing.

    Say you generate a huge number of sequential integers. That sequence of
    integers is:
    - randomly distributed (no integer appares more commonly than any other
    one);
    - has an arbitrarily long period (as long as you want it to be), BUT
    - is totally predictable! Once you know what number the generator just
    emitted, you instantly know every successive number that it will emit!
    This would be hopeless to base a cipher on.

    So my generator, which I offered as an instructive joke, was only meant
    to illustrate that randomness is /not enough/, and having a long period
    is also /not enough/. The numbers must also be /unpreictable/ - a
    completely different thing.

    Cheers,
    TC

  • Next message: Joseph Ashwood: "Re: Looking for an encryption program"

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