Problem Cross - Posted fron Sci Crypt Crypto Group

[Austin Obyrne <austin.obyrne@hotmail.com>]

My invention of scrambling of the cipher text as an invincible way of securing it against cryptanalysis has stalled at file sizes of 30000 plaintext items. This isn't bad but I want to go further.

I post here some scrambling extracts from my development work that show that my current programs will work on files up to 30000 items but not on a file of 50000 characters.  I cannot find any reason for this happening and I think there may be something in the Ada language that perhaps sets a latent bound on what I am trying to do. 

1) File size : 30000 items

SliceNum_26  : CONSTANT Integer := 0; --Start point in slice  of a ciphertext string in hand    
StepNum_26   : CONSTANT Integer := 45; -- Upstream placemoves  from A to B in this string     
RepeatsNum_26: CONSTANT Integer := 2099; -- make repeats of placemoves instruction  
  -- scrambling device in ''Load_n_Scramble_CipherTexts'' procedure 
  -- (SliceNum_26 + stepNum_26*RepeatsNum_26 <= Current number of ciphertext items.

There are 94491 items of ciphertext in the largest string in hand on this occasion i.e. 31497 vectors that have 31497 x 3 = 94491 coefficients

My program handles this quite OK - no problem in transposing the elements of ciphertext

When I try to scramble a larger program as follows however I get a " CONSTRAINT ERROR " annunciation.



2) File size : 50000 items.

SliceNum_26  : CONSTANT Integer := 0; --Start point in slice  of the  ciphertext string  in hand    -
StepNum_26   : CONSTANT Integer := 29; --Upstream placemoves  from A to B in this string     
 RepeatsNum_26: CONSTANT Integer := 5179; --repeats of placemoves instruction  
  -- scrambling device in ''Load_n_Scramble_CipherTexts'' procedure 
  -- (SliceNum_26 + stepNum_26*RepeatsNum_26 <= Current number of ciphertext items.

The second program is comprised of 527 repeats of the ASCII set of 95 characters i.e. 50065 characters.  Each character is transformed into a displacement vector that has 3 coefficients so that there are 50065 x 3 = 150195 coefficients that comprise the ciphertext string for scrambling this second time.

The program will not run and I repeat, I get an error message "CONSTRAINT ERROR"

My problem:-

This encryption of what might be a fairly large general office program runs perfectly in another (different) program where it is not required to scramble the ciphertext but crashes when it is asked to do so according to the new scrambling parameters in my desired development(different)scrambling program i.e. the parameters 29 x 5159 that were OK earlier for scrambling seem to be too much for it to scramble now when the parameters are 45 x 2099.

Question:- What is causing this.

I have gone over all of the other coincident possibilities that might cause a constraint error in the scrambling of this larger program and I cannot see anything that might do it.  I am slowly coming to the conclusion that it must be to do with the number of I_O ( IN - OUT) operations that the scrambling operation requires.  Am I exceeding some latent upper bound in the Ada language - alternatively it is unlikely to be computer-related I think ?.

My CS knowledge doesn't go far enough to do any analysis or solution and I would be grateful for more informed help from anybody.

*I am using a very old compiler - Gnat 311.p - and a typical home computer that has Windows 7 operating system,  It has a fairly good processor however.
 
Any help would be appreciated

Comment:

This does not affect the future of scrambling the ciphertext as a future ploy in general cryptography.  It just means that in my present case I seem to be limited to encrypting plaintext files of 30000 in extent only *i.e. if I decide to scramble the ciphertext string after encrypting it.

Austin O'Byrne