My Math Forum Affine transformation and RSA cipher

 Number Theory Number Theory Math Forum

 February 24th, 2009, 07:58 AM #1 Member   Joined: Jan 2009 Posts: 30 Thanks: 0 Affine transformation and RSA cipher 1. If the two most common letters in a long ciphertext, enciphered by a an affine transformation C is congruent aP + b (mod 26) are W and B, respectively, then what are the most likely values for a and b? 2. This message WEZBF TBBNJ THNBT ADZQE TGTYR BZAJN ANOOZ ATWGN ABOVG FNWZV A was enciphered using an affine transformation C is congruent to aP + b (mod 26): Suppose it is know that the most common letters in the plaintext message are A, E, N, and S. Use the frequency of letters to determine a and b. Then decrypt the message. 3. If the ciphertext message produced by the RSA cipher with key (e; n) = (13; 2747) is 2206 0755 0436 1165 1737 what is the plaintext message?
 February 25th, 2009, 07:47 PM #2 Member   Joined: Jan 2009 Posts: 30 Thanks: 0 Re: Affine transformation and RSA cipher can anybody help me out with this??
 March 12th, 2009, 03:36 AM #3 Newbie   Joined: Mar 2009 Posts: 4 Thanks: 0 Re: Affine transformation and RSA cipher For the first cyphertext: plaintext= "this message was enciphered using an affine transformation"
 March 12th, 2009, 04:46 AM #4 Newbie   Joined: Mar 2009 Posts: 4 Thanks: 0 Re: Affine transformation and RSA cipher For the second cyphertext: 2747=41*67 phi(2747)=40*66=2640 and 13*2437=1 mod 2640 Decryption key is (2437,2747) Decryption: 2206^2437 mod 2747=617 0755^2437 mod 2747=404 0436^2437 mod 2747=1908 1165^2437 mod 2747=1306 1737^2437 mod 2747=1823

 Tags affine, cipher, rsa, transformation

,

# tgtyr

Click on a term to search for related topics.
 Thread Tools Display Modes Linear Mode

 Similar Threads Thread Thread Starter Forum Replies Last Post threesixtify Applied Math 0 January 22nd, 2013 05:53 AM ggyyree Calculus 0 July 27th, 2010 05:59 AM maximilian Algebra 0 June 18th, 2010 12:50 PM arnav.akash9 Linear Algebra 0 November 17th, 2009 04:41 PM dervish Algebra 0 May 23rd, 2008 08:23 AM

 Contact - Home - Forums - Cryptocurrency Forum - Top