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Thread: Regarding Digi Secret.

  1. #16
    Join Date
    Jun 2001
    Posts
    398

    The passphrase in digi secret.

    hi,

    The digisecret pass phrase can accept 256 symbols
    (charecters),the ascii charecters from 0-255
    It would be a good idea to utilise the entire space
    provided for the pass phrase,atleast *28 charecters
    would be good
    To generate the ascii charecter in the passphrase
    use the alt+ascii-number.

    If the Ascii set charecters is used an exhaustive brute
    force would on a *28 charecter pass phrase would take
    (if ^ denote exponent)
    256^*28=*.7*76****4862**5*0772**05**078*e+*08
    attempts.
    A 256 charecter pass phrase take
    256^255=*.262*8*04*660586222684*7487065*e+6*4
    attempts if the passphrase used contains the charecter
    of the ascii set.
    Both are whopingly large numbers!
    It would be a good idea to use a phrase longer than *28
    charecters and to make use of the entir ascii set for
    the pass phrase.

    Regards Data.

  2. #17
    Unregistered Guest

    Awesome

    Wish that I was that advanced Regards, Newbietoo

  3. #18
    Join Date
    Jun 2001
    Posts
    398
    HI,

    the idea behind brute force is pretty simple.

    I'll try to make this simple.

    Suppose ur passwd is ' z ' with out the quotes of course.

    Now since a classical brute force checks for all combinations.

    In english there are 26 alphabets (a-z)

    So if u brute force 'z ' ,the passwd is found in 26 attempts.


    Now if ur passwd is ' zz '
    A complete brute force will take 26 * 26 attempts.


    For an 8 alphabet word,the complete brute force takes

    26*26*26....*26(8 times)

    I just use ^ to represent power or exponent.


    26*26*26....*26(8 times)=26^8


    Now if my passwd uses both capital and small letters.

    For an extensive brute force now we have to search for both capital and small letters.
    If there is * alphabet in the passwd we dont know if it is capital or small letter.

    So total brute force takes (26+26)=52 attempts for breaking a passwd of * charecter length.

    Extending it to 8 charecters,if the passwd use both capital and small letters.

    52*52*52.....*52(8 times)
    which is equal to 52^8.

    Here the key space is small.(A pass phrase is not a key exactly,how ever it is used to generate the keys).

    For the sake of generality lets consider a pass phrase as a key.
    Since there are 256 ascii charecters if u use,the difficultly of brute force increases drastically.

    if ur passwd consists any * of these 256 ascii charecters,it takes 256 attempts for a complete brute force.

    If u use a *28 charecter passwd ,brute force needs
    256^*28 attempts

    If u use a 255 charecter passwd ,(255 being the maximum input space for digisecret)brute force needs
    256^255 attempts.

    Regards Data.

  4. #19
    Join Date
    Jun 2001
    Posts
    398
    hi,

    Hope that explanation is understood for the very reason i omitted the word permutations & combinations

    Here is a thread of a c programme that illustrates the idea of a brute force.
    The programme hardly does any thing but u will get the concept.

    the thread is

    [url]http://www.all-nettools.com/forum/showthread.php?threadid=265[/url]

    Look for subject Brute force.

    I thought it was silly of me to post that,any way hope that it will be of use now :P

    regards Data.

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