Results 1 to 3 of 3

Math Help - Pohlig-Hellman Cipher + Affine Hill Cipher, relatively simple (not for me!) questions

  1. #1
    Newbie
    Joined
    Jan 2013
    From
    Finland
    Posts
    1

    Pohlig-Hellman Cipher + Affine Hill Cipher, relatively simple (not for me!) questions

    Hi guys,

    How you all doing?

    Would be a great help if you could help me solve these equations. I guess more than the answers I need the process by which you get to them.

    Here are the questions:

    ---------------------------------------------------------------------------------------------------------------------------------------------------------

    1) The cryptotext 3276 is a result of the Pohlig-Hellman Cipher with p = 7823 and e = 3129. Find the Plaintext.

    Encryption algo: Ee(x) =xe (mod p)
    Decryption algo: Dd(y) = yd (mod p)

    ---------------------------------------------------------------------------------------------------------------------------------------------------------

    2) The Affine Hill Ciper has the encryption function

    E(x^1,...,x^m) = (x^1,...,x^m) A+(b^1,...,b^m) (mod 26)

    where A is invertible m x m matrix. Encrypt the message "tavern" using the encryption key m=2, A= (see matrix below)

    ( 4 11
    3 19 )

    and (b^1, b^2) = (13, 5).

    Check your result by decrypting.

    ---------------------------------------------------------------------------------------------------------------------------------------------------------

    Ok. That's it!

    Any and all help would be appreciated... Thankss




    Last edited by threesixtify; January 22nd 2013 at 04:46 AM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Sep 2012
    From
    Australia
    Posts
    3,651
    Thanks
    602

    Re: Pohlig-Hellman Cipher + Affine Hill Cipher, relatively simple (not for me!) quest

    Hey threesixtify.

    Can you show us what you have tried? Also do you have a software package that can do the matrix and mod operations? (A free package is Octave that you can download with GUIOctave as a GUI front end).
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Jan 2013
    From
    Varissuo
    Posts
    1

    Re: Pohlig-Hellman Cipher + Affine Hill Cipher, relatively simple (not for me!) quest

    Moi threesixtify,
    Mita kuuluu ?

    you can find "d" by using e.d = 1(mod p-1) [where '=' means congruent]
    Then apply the decryption formula which you have mentioned.

    And yes you are right, Steps are required if Tomi asks to solve (this 25% of the questions) on the board :P

    Which batch are you in ? 10-12 or 12-2 ?

    nähdään huomenna

    Terveisin
    AliceBobEve
    Last edited by AliceBobEve; January 24th 2013 at 09:37 AM.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] diophantine equations in hill cipher decryption
    Posted in the Number Theory Forum
    Replies: 2
    Last Post: March 15th 2011, 09:54 AM
  2. Hill 2-Cipher Decryption
    Posted in the Advanced Algebra Forum
    Replies: 0
    Last Post: September 28th 2010, 01:45 PM
  3. Hill Cipher, how did they do it ?
    Posted in the Advanced Algebra Forum
    Replies: 1
    Last Post: August 29th 2010, 03:59 PM
  4. affine cipher
    Posted in the Discrete Math Forum
    Replies: 14
    Last Post: August 25th 2010, 05:09 AM
  5. Hill Cipher Problem
    Posted in the Advanced Algebra Forum
    Replies: 1
    Last Post: March 10th 2006, 10:58 AM

Search Tags


/mathhelpforum @mathhelpforum