Re: Cracking decrypted file when knowing partial contents

From: Bill Unruh (unruh_at_string.physics.ubc.ca)
Date: 04/21/04

  • Next message: Barry Margolin: "Re: incoming mail without information in the from, to, subject fields" 
    Date: Wed, 21 Apr 2004 17:43:44 +0000 (UTC)

    "David A. Scott" <daVvid_a_scott@email.com> writes:

    ]unruh@string.physics.ubc.ca (Bill Unruh) wrote in
    ]news:c6472g$312$1@string.physics.ubc.ca:

    ]>
    ]> No encryption can guarentee anything. They are however designed to be
    ]> resistant to known plaintext attacks (ie attacks which make use of
    ]> knowing both the plaintext and the encrypted text). Any crypto system
    ]> which is weak if plaintext is known, is weak period.
    ]>
    ]>

    ] No even systems your talking about are weak in the sense that a
    ]few paragraphs of plaintext would be more than enough to guarantee
    ]that an attacker has all the information necessiary for a break.

    Might you perhaps suggest how you would break, lets say DES, even if I
    gave you 1MB of plain text other than by exhaustive search?

    ]What your calling strong are only strong because there are no published
    ]breaks but that does not mean someone will not find a trival break.
    ]What is strong today tends to become weak as time marches on.

    Yes. And? That is always true. In 50BC the Ceasar cypher was strong. It
    is not now. So? If your secret must really remain secret but readable
     for 100 years, you are probably in trouble with any cypher.

  • Next message: Barry Margolin: "Re: incoming mail without information in the from, to, subject fields"

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