Talk:RSA code

Draft

There's a lot to do to clean this up to the level of being a full task. For one thing, it's not at all clear what this code is trying to do! It also lacks links to resources (e.g., wikipedia) that describe the algorithm involved, and the Python solution needs much work too (especially in its surrounding descriptive text, which looks to me more like text that belongs here on the talk page). –Donal Fellows 06:31, 24 March 2011 (UTC)

+1 on Dkf's comments. How to perform the task needs to be in the task description in a more language neutral form. --Paddy3118 13:12, 24 March 2011 (UTC)

Sorry about the shoddy state of my code, it's one of the first programs i have written on my own, and there are probably far more efficient ways of performing many functions that i just brute forced my way past. But it works, and i am rather proud of it, ugly as it may be. I have added detail about the function of the code and the way the RSA algorithm works. Please let me know if there is anything else i can clear up! --Erasmus 03:00, 26 March 2011 (UTC)

Blocking?

"This yields two blocks of numbers ..." I can see that a series of numbers are produced, but the method of splitting into blocks is not given. --Paddy3118 02:45, 26 March 2011 (UTC)

The blocking code is more complicated than the encryption code. But:

• When converting letters to numbers, the numbers should be non-zero.
• If if X is the largest number value, then pick the largest K such that (1+X)^K < N (where N is from the key). K is the number of letters represented in a block.
• If v is an array of numbers repesenting the letters in a block, the numeric value of the block itself is can be computed (using psuedo-C or maybe psuedo-javascript):

   block= 0;
   for (int i= 0; i<v.length; i++) {
       block= v[i]+(X+1)*block;
   }

• To go the other direction:

   for (int i= v.length-1; i >= 0; i--) {
       v[i]= block % (X+1);
       block= block / (X+1); /* integer division */
   }

--Rdm 03:31, 26 March 2011 (UTC)