Re: Re: Determining the encryption used

From: cwright@bdosyd.com.au
Date: Fri May 12 2006 - 18:26:10 EDT

('binary' encoding is not supported, stored as-is) Hello,
To throw in my 5 cents (2cents being abolished in AU)

There are a couple classes to consider. First is the obvious. If there are headers and footers that allow analysis than these are covered early.

Next if we look at classes where there are no headers etc to see directly what it is, there is a level of analysis required.

First is the data chunked? Does it conform to set blocks. Is it streamed?

Is there any surrounding stream information that can help?

Inferential Statistics and a good program for data mining will help. but this would be another 300-800 pages to post.

Grab a book;
Differential Cryptanalysis of the Data Encryption Standard
by Eli Biham, Adi Shamir

or as an intro to the subject;
Cryptanalysis
by Helen F. Gaines

In reality this is not a question that can easily be answered. It needs to be fleshed out. Where was the data obtained. In a file and extracted, from a stream? What supporting information is there? How was it created? How was it found? What permissions does it have?.......

Regards,
Craig

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