howto discover which algorithm is used to encrypt a file

Posted on 2005-04-14
Last Modified: 2010-05-02
Dear Experts,

I got a file which is encrypted with some sort of algortihm but i don't know with which algorithm. Is there any way you can discover which one is used? maybe by looking at it's patern or something like that?

Greets Erik
Question by:WarLord
    LVL 85

    Expert Comment

    by:Mike Tomlinson's called trial and error.

    Basically you try every "known" decryption algorithm and if you get something that matches the "known pattern" or yields readable results then you're done.

    If the file was encrypted with an "unkown" algorithm then you have to crack the file yourself.

    Alternatively, you can ask our government if you can borrow their top secret little black box that was developed for the specific purpose of decrypting any file no matter how it was encrypted.

    Seriously though, WarLord, we are not allowed to help you decrypt files.


    Author Comment

    I'm not asking you to decrypt my files i was just interested if there was a way to discovery which algorithm was used. No hard feeling if it isn't possible.
    LVL 85

    Assisted Solution

    by:Mike Tomlinson
    Well...most files aren't "tagged" with a header describing what encryption algorithm was used if that's what you are asking.  The file may not even be encrypted, it may just have its own binary format.

    Describe what you are doing in more detail and we "may" be able to help you.

    Without more specifics then my first post is as close as you can get.  ;)
    LVL 2

    Accepted Solution


    Maybe the file isn't ecrypted? Did you "looked" into the file with a binary editor? What kind of file is it (extenction)? Maybe it is just compresed? Try to use "IsoBuster" or something like that...


    Author Comment

    file extension is .lioc i will have a look with a binary editor
    LVL 2

    Expert Comment


    I also came across that:

    Is that all about?

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